Effect of Selenium Priming duration on Germination and Early Seedling Development of Arachis hypogaea L. Across a Salinity Gradient

Effect of Selenium Priming duration on Germination and Early Seedling Development of Arachis hypogaea L. 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Across a Salinity Gradient Eromosele Noble Isibor¹, Rida Batool², Boniface Edegbai³, Ifie Etumah Sandra, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8605366/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 17 You are reading this latest preprint version Abstract Soil salinity as a result of global warming and poor agro-cultural practices poses a significant challenge to food production. Selenium (Se) has emerged as a promising micronutrient capable of mitigating abiotic stress in plants by reducing reactive oxygen species and supporting cellular metabolism. This study investigated the effects of selenium seed priming on germination and early seedling development of an Arachis hypogaea L. landrace under a gradient of saline conditions. Seeds were primed with selenium at five concentrations (0, 1.5, 2.5, 5, and 10 mg L⁻¹) for three durations (3, 6, and 9 h) and sown in Petri dishes containing sodium chloride solutions ranging from 0 to 7 g L⁻¹. Germination indices—including germination percentage, mean germination time, germination rate index, and germination velocity—along with seedling growth parameters and biochemical contents were evaluated. A composite Z-score integrating all measured parameters was used to rank the most effective selenium treatment at each salinity level. Selenium treatments exhibited concentration-dependent responses, with lower to moderate concentrations showing optimal or suboptimal effects, while higher concentrations induced inhibitory effects, indicating a clear hormetic response. These findings demonstrate that selenium seed priming at appropriate concentrations and durations represents a simple and cost-effective strategy for enhancing peanut establishment under saline soil conditions. Selenium priming Arachis hypogaea Salinity stress Seed germination Early seedling growth Hormesis Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 INTRODUCTION Soil salinity is one of the most severe abiotic stresses limiting agricultural production worldwide, particularly in arid and semi-arid regions (Munns and Tester 2008 ). Global warming associated with climate change has intensified this problem by increasing soil water evaporation and altering rainfall patterns, leading to the accumulation of soluble salts in agricultural soils and the flooding of farmlands in coastal areas with saline water (IPCC 2022). Poor irrigation practices and inadequate drainage systems further exacerbate soil salinization in many developing countries, resulting in reduced crop establishment, growth, and yield, and consequently increasing food insecurity (FAO 2021 ). Salinity is especially detrimental during germination and early seedling development due to osmotic stress, excessive accumulation of sodium and chloride ions, and oxidative damage caused by the overproduction of reactive oxygen species (ROS) (Zhu 2001 ; Hasanuzzaman et al., 2014 ). These effects disrupt cellular metabolism, enzyme activity, and membrane integrity, ultimately reducing germination efficiency and seedling establishment—developmental stages that are highly sensitive to osmotic stress and ion toxicity (Zhu 2001 ). Groundnut ( Arachis hypogaea L .) is an economically important legume cultivated extensively for its oil content, protein value, and contribution to household income and food security, particularly in sub-Saharan Africa (Upadhyaya et al., 2014 ). However, groundnut is considered moderately to highly sensitive to salinity, with adverse effects reported on germination rate, seedling vigor, and biomass accumulation (Mensah et al., 2006 ; Abbas et al., 2015 ). In Nigeria and similar agro-ecological regions where groundnut is cultivated, production relies largely on locally adapted landraces grown by smallholder farmers. These landraces are often preferred for their adaptability and availability but generally lack improved tolerance to increasing soil salinity, making early seedling failure a major constraint to local productivity. Although genetic improvement for salt tolerance represents a desirable long-term solution, it is time-consuming and frequently inaccessible for locally important landraces. Consequently, there is growing interest in low-cost agronomic interventions that enhance early-stage stress tolerance. Selenium, although not essential for higher plants, has been shown at adequate concentrations to improve ion homeostasis, reduce sodium uptake, and enhance osmotic adjustment, thereby contributing to improved stress resilience (Hawrylak-Nowak 2009 ). However, selenium exhibits a narrow margin between beneficial and toxic concentrations, and excessive application can impair growth and induce oxidative stress rather than alleviate it (White 2016 ). As a result, plant responses to selenium vary widely among species, genotypes, developmental stages, and application methods. Information remains particularly limited for locally cultivated landraces exposed to varying levels of salinity stress. Moreover, there is no consensus on optimal selenium priming concentrations and durations, especially for leguminous crops such as groundnut (Khan et al., 2023 ; El-Badri et al., 2022a ; Hussain et al., 2023 ). These gaps highlight the need for systematic evaluation of selenium priming regimes to better understand their physiological effects during germination and early seedling development under saline conditions (Cunha et al., 2022 ; García-Locascio et al., 2024 ). Therefore, this study investigates the effects of selenium seed priming at different concentrations and durations on germination and early seedling growth of a locally adapted Arachis hypogaea landrace subjected to a gradient of salinity stress. By integrating multiple germination indices and seedling growth parameters, this work aims to identify an effective selenium priming strategy that can enhance early seedling establishment in Arachis hypogaea and provide a practical, low-cost intervention for smallholder farmers operating in salt-affected environments. Materials and Methods Research Design A randomized three-factorial experimental design was adopted. The factors were selenium concentration, priming duration, and salt concentration. This design enabled evaluation of the individual and interactive effects of selenium priming, priming duration, and salinity on germination and early seedling development. Seed Source Seeds of ‘Auchi groundnut’, an Arachis hypogaea L . landrace cultivated in Auchi, Etsako West Local Government Area, Edo State, Nigeria, were purchased from New Benin Market, Benin City. This landrace was selected due to its widespread cultivation by local farmers, making it representative of peanut production systems in the region. Preparation of Salt and Priming Solutions Selenium priming solutions were prepared using sodium selenite (Na₂SeO₃). The required quantities for each selenium concentration (1.5, 2.5, 5.0, and 10 mg L⁻¹) were calculated, accurately weighed, and dissolved in 1 L of distilled water. Disposable, labeled cups corresponding to priming durations (3, 6, and 9 h) were used for priming. Seeds in the control treatment (0 mg L⁻¹ selenium) were sown without selenium hydro-priming. Sodium chloride (NaCl) solutions of five concentrations (0, 1.5, 3.5, 5.0, and 7.0 g L⁻¹) were prepared by dissolving the appropriate mass of NaCl in 1 L of distilled water. Seed Preparation, Priming, and Sowing Seeds were surface-sterilized with 1.5% sodium hypochlorite, rinsed thoroughly with distilled water, and air-dried. Thereafter, seeds were soaked in 150 mL of the respective selenium solutions for each priming duration. To ensure uniform selenium uptake, 75 seeds per selenium concentration were divided into three batches of 25 seeds, corresponding to each priming duration. Five selenium-primed seeds and unprimed control seeds were sown across all salinity treatments in labeled Petri dishes containing 5 mL of the appropriate salt solution. Each selenium × priming duration × salt concentration treatment combination was replicated three times. Moisture was maintained by daily addition of 6 mL of distilled water to minimize drying. Experimental Duration The experiment was terminated 10 days after sowing. Measured Parameters Germination Percentage (GP) Seed with at least 2 millimeter radicle protrusion were counted as germinated seeds. Germinated seed were recorded daily for ten days. Final germination percentage was calculated as; $$\:GP=\frac{\:Number\:of\:seeds\:germinated\:\:\:\:\:\:}{Total\:\:number\:\:of\:seeds\:sown}\:\times\:100$$ Mean Germination Time (MGT) = $$\:\:\:\:\:\:MGT=\frac{\sum\:({n}_{i}\times\:{t}_{i})}{\sum\:{n}_{i}}$$ \(\:{n}_{i}\) = number of seeds germinated on day \(\:i\) \(\:{t}_{i}\) = time (days) from sowing \(\:i\) \(\:\sum\:{n}_{i}\) = total numbers of germinated seeds Germination Rate Index (GRI) $$\:GRI=\sum\:\left(\frac{{G}_{i}}{{t}_{i}}\right)\:\:\:\:\:$$ \(\:{G}_{i}\) = number of seeds germinated on day \(\:i\) . \(\:{t}_{i}\) = Time in days from sowing to the \(\:i\) -th day. Germination Velocity (GV) $$\:GV=\sum\:\left(\frac{{n}_{i}}{{t}_{i}}\right)$$ \(\:{n}_{i}\) = number of seeds germinated on day \(\:i\) \(\:{t}_{i}\) = times (days) from sowing to day \(\:i\) Additional data are given in Online resource 1. Shoot and Radicle Length Shoot and radicle lengths were measured in centimeters using a ruler. Seedling Dry Weight Seedlings were oven-dried at 70°C for 4 h and weighed using an analytical balance (± 0.001 g). Number of Leaflets The number of leaflets per seedling was counted manually. Total Chlorophyll Content Total chlorophyll content was determined following the method of Arnon ( 1949 ). Proline Content Proline content was determined using the acid-ninhydrin method, with absorbance measured at 520 nm (Bates et al., 1973 ). Composite Z-Score Calculation To integrate germination, seedling growth, and biochemical traits into a single performance index, standardized z-scores were computed following Munns and Tester ( 2008 ). Traits for which lower values indicate better performance (e.g., MGT) were multiplied by − 1 prior to integration. The composite Z-score was calculated as the mean of standardized trait values: $$\:{\text{z}}_{i}=\frac{{x}_{i-\overline{X}}}{{S}_{x}}$$ $$\:{z}_{composite}=\frac{1}{n\:\:}\:\times\:\sum\:{z}_{i}$$ Where; \(\:{S}_{x}\) = standard deviation $$\:{\text{Z}}_{i}=\:\text{v}\text{a}\text{l}\text{u}\text{e}\:\text{o}\text{f}\:\text{t}\text{r}\text{a}\text{i}\text{t}\:i.$$ \(\:{x}_{i}\) = observed value of the trait for a given treatment. \(\:\stackrel{-}{x}\) = mean of the trait across the treatment n = number of trait in the composite This approach enabled a transparent and quantitative comparison of overall seedling performance across treatments, accounting for partial growth responses and variability among seedlings, and facilitating identification of the most effective selenium concentration × priming duration combinations at each salinity level. Data Analysis All data processing, calculations, statistical summaries, and visualizations were performed using Python within a Jupyter Notebook environment. Computational workflows were assisted by AI-based language models for code development and verification, while all statistical decisions and biological interpretations were made by the authors. Results Germination Germination in the non-primed control (Se0–0 h) followed a consistent decline across salinity levels (Fig. 1 ). Under non-saline conditions (0 g L⁻¹ NaCl), germination reached 66.7%, with standard deviations ranging from ± 0.0% to ± 30.0% among treatments, but typically within ± 10.0–11.5%. Germination declined to 53.3% at 3.5 g L⁻¹ NaCl, 40.0% at 5 g L⁻¹ NaCl (SD ± 0.0–11.5%), and 13.3% at 7 g L⁻¹ NaCl (SD ± 11.5%), with significant reductions (p < 0.05) observed from 5 g L⁻¹ NaCl relative to lower salinity levels. Responses to selenium priming depended on selenium concentration, priming duration, and salinity level. Priming duration exerted a strong influence across treatments. Under low or no salinity (0–1.5 g L⁻¹ NaCl), 3 h and 6 h priming durations generally outperformed 9 h priming, which frequently resulted in significantly lower germination (p < 0.05). At moderate salinity (3.5–5 g L⁻¹ NaCl), 6 h priming was most effective, particularly at 2.5 and 5 mg L⁻¹ Se. Under severe salinity (7 g L⁻¹ NaCl), 6 h priming remained optimal at low-to-intermediate selenium concentrations, whereas 3 h priming provided greater benefits at higher selenium levels. Across all salinity levels, 9 h priming consistently produced the lowest germination values. Radicle Length Radicle length responses to increasing NaCl concentrations (0–7 g L⁻¹) following selenium priming (1.5, 2.5, 5, or 10 mg L⁻¹ for 3, 6, or 9 h) are presented in Fig. 2 . In non-primed controls, radicle length remained relatively stable between 0 and 3.5 g L⁻¹ NaCl (approximately 1.85–1.88 cm) but was completely inhibited at 5 and 7 g L⁻¹ NaCl. Under non-saline conditions, priming with 1.5–5 mg L⁻¹ Se significantly increased radicle elongation, with maximum length (2.80 cm) observed after 3 or 9 h at 5 mg L⁻¹ Se. In contrast, priming with 10 mg L⁻¹ Se caused a duration-dependent reduction in radicle length, reaching 0.80 ± 0.35 cm after 9 h. At 1.5 g L⁻¹ NaCl, the longest radicles occurred after 3 h priming at 1.5 mg L⁻¹ Se, while higher selenium concentrations offered no advantage over the control. At 3.5 g L⁻¹ NaCl, priming with 1.5–2.5 mg L⁻¹ Se preserved or slightly enhanced radicle length, whereas higher concentrations reduced elongation. Under severe salinity (5–7 g L⁻¹ NaCl), where control seedlings showed no radicle growth, priming with 2.5–5 mg L⁻¹ Se restored residual elongation, with maximum values of 2.10 cm at 5 g L⁻¹ NaCl and 1.60 cm at 7 g L⁻¹ NaCl. Shoot Length Shoot length responses under identical treatments are shown in Fig. 3 . Shoot length in control seedlings declined progressively with increasing salinity and was completely inhibited at 5 and 7 g L⁻¹ NaCl. Under non-saline conditions, selenium priming significantly enhanced shoot elongation at all concentrations, with the greatest increases recorded at 1.5–2.5 mg L⁻¹ Se after 9 h priming, reaching 3.70 ± 0.35 cm. At 10 mg L⁻¹ Se, shoot enhancement was reduced and declined with increasing priming duration. At 1.5 and 3.5 g L⁻¹ NaCl, priming with 1.5–2.5 mg L⁻¹ Se maintained shoot length near control values, whereas higher selenium concentrations resulted in reduced elongation. Under severe salinity, residual shoot growth was confined to 6 h priming durations, with maximum shoot length of 0.70 ± 0.30 cm at 5 g L⁻¹ NaCl and minimal elongation (0.20 ± 0.15 cm) at 7 g L⁻¹ NaCl. Number of Leaflets per Seedling The number of leaflets per seedling declined with increasing salinity (Fig. 4 ) and was completely absent at 5 and 7 g L⁻¹ NaCl in control treatments. Under non-saline conditions, selenium priming enhanced leaflet production, with maximum values of 17.5 ± 1.5 leaflets after 9 h at 1.5 mg L⁻¹ Se and 16.5 ± 1.5 leaflets after 9 h at 2.5 mg L⁻¹ Se. At 1.5–3.5 g L⁻¹ NaCl, lower selenium concentrations maintained leaflet numbers close to control values, whereas 10 mg L⁻¹ Se reduced leaflet production. At 5 g L⁻¹ NaCl, priming partially restored leaflet emergence, peaking at 4.0 ± 0.8 leaflets after 6 h priming at 5 mg L⁻¹ Se. Total Chlorophyll Content Total chlorophyll content declined progressively with increasing salinity in control seedlings (Fig. 5 ), decreasing from 1.87 ± 0.03 mg g⁻¹ FW at 0 g L⁻¹ NaCl to 1.17 ± 0.03 mg g⁻¹ FW at 3.5 g L⁻¹ NaCl, and was undetectable at 5 and 7 g L⁻¹ NaCl. Selenium priming at 1.5–5 mg L⁻¹ significantly enhanced or maintained chlorophyll content under 0–3.5 g L⁻¹ NaCl, with peak values exceeding 2.60 mg g⁻¹ FW at intermediate priming durations. In contrast, 10 mg L⁻¹ Se reduced chlorophyll content across all salinity levels. At 5 g L⁻¹ NaCl, residual chlorophyll content reached a maximum of 0.49 ± 0.05 mg g⁻¹ FW, while no chlorophyll was detected at 7 g L⁻¹ NaCl Proline Content Proline content increased markedly with salinity in control seedlings (Fig. 6 ), rising from 5.83 ± 0.40 µmol g⁻¹ FW at 0 g L⁻¹ NaCl to 73.00 ± 2.65 µmol g⁻¹ FW at 3.5 g L⁻¹ NaCl, and was undetectable at 5 and 7 g L⁻¹ NaCl. Selenium priming at 1.5–5 mg L⁻¹ attenuated proline accumulation under mild salinity stress. In contrast, priming with 10 mg L⁻¹ Se strongly induced proline accumulation even under non-saline conditions and further amplified levels under salinity stress, reaching approximately 260 µmol g⁻¹ FW under moderate stress and 320 µmol g⁻¹ FW under severe stress. All selenium treatments enabled substantial proline synthesis under severe salinity conditions. Seedling Dry Weight Seedling dry weight decreased with increasing salinity in control treatments (Fig. 7 ) and was undetectable at 5 and 7 g L⁻¹ NaCl. Selenium priming significantly enhanced biomass accumulation under 0–3.5 g L⁻¹ NaCl, with maximum values recorded at 2.5–5 mg L⁻¹ Se after longer priming durations, reaching 0.195 ± 0.018 g. Under severe salinity, priming enabled residual biomass accumulation, with maximum dry weights of approximately 0.110 g at 5 g L⁻¹ NaCl and 0.050 ± 0.012 g at 7 g L⁻¹ NaCl. Composite Z-Score Composite Z-scores revealed clear selenium- and salinity-dependent responses (Fig. 8 ). Under non-saline conditions (0 g L⁻¹ NaCl), the highest composite score (1.193) was obtained with 1.5 mg L⁻¹ Se primed for 6 h. At 1.5 g L⁻¹ NaCl, priming with 5 mg L⁻¹ Se for 6 h produced the highest composite score (1.045). At 3.5 g L⁻¹ NaCl, priming with 2.5 mg L⁻¹ Se for 6 h yielded the highest composite score (0.692). At higher salinity levels (5–7 g L⁻¹ NaCl), priming with 2.5 mg L⁻¹ Se for 3 and 6 h resulted in the best overall performance, although composite scores were negative (− 0.431 and − 0.611), reflecting the severity of stress at these salinity levels. Discussion Plants are not passive recipients of environmental stress; rather, they possess sophisticated sensing and signaling systems that enable perception and adaptive responses to adverse conditions such as salinity. Stress perception begins at the root–soil interface, where changes in ionic composition (Na⁺, K⁺, and Cl⁻ imbalance), osmotic pressure, and early bursts of reactive oxygen species (ROS) are detected by membrane-associated sensors, ion channels, and redox-sensitive proteins (Zhu, 2002 ; Munns and Tester, 2008 ; Shabala and Pottosin, 2014). These early signals activate downstream signal transduction pathways involving secondary messengers such as Ca²⁺, ROS, nitric oxide, and protein phosphorylation cascades, collectively initiating adaptive responses and fine-tuning stress-responsive gene expression networks (Knight and Knight, 2001; Suzuki et al ., 2012; Mittler, 2017). Salinity stress is particularly damaging because it combines osmotic stress with ion toxicity, resulting in rapid and sustained ROS accumulation. Although ROS function as essential signaling molecules at low concentrations, excessive ROS disrupt membrane integrity, oxidize proteins and nucleic acids, interfere with protein folding, and impair cellular metabolism (Apel and Hirt, 2004; Mittler et al ., 2011; Foyer and Noctor, 2013). Oxidative stress therefore compromises early developmental processes such as seed germination and seedling establishment, which are especially sensitive to redox imbalance. Within this framework, selenium functions not merely as a general antioxidant but as an active modulator of cellular redox homeostasis, particularly when applied via seed priming. Selenium is incorporated into selenoproteins, including glutathione peroxidases (GPXs) and thioredoxin reductases (TRXs), which play central roles in detoxifying hydrogen peroxide and lipid hydroperoxides while maintaining intracellular redox balance (Pilon-Smits et al., 2009 ; Schiavon et al., 2016 ; Hasanuzzaman et al., 2020 ). These enzymes stabilize cellular redox potential, protect cysteine residues from oxidation, and preserve the structural and functional integrity of stress-responsive proteins. A key molecular consequence of excessive ROS accumulation under salinity stress is the oxidation of cysteine residues in regulatory proteins. Many stress-responsive transcription factors, including members of the DREB, bZIP, and NAC families, contain redox-sensitive thiol groups essential for maintaining proper protein conformation and DNA-binding activity (D’Autréaux and Toledano, 2007 ; Foyer and Noctor, 2005; Dietz, 2014 ). Oxidation of these thiols disrupts transcription factor–DNA interactions, thereby suppressing stress-responsive gene expression. Selenium-mediated ROS scavenging helps preserve thiol redox status, enabling effective transcription factor binding and sustained transcriptional activation of protective genes (Sors et al., 2005 ; Pilon-Smits and Quinn, 2010 ; Schiavon and Pilon-Smits, 2017 ). Once transcriptional regulation is maintained, downstream expression of genes encoding antioxidant enzymes—such as superoxide dismutase (SOD), catalase (CAT), and peroxidases—as well as enzymes involved in osmolyte biosynthesis (e.g., proline and glycine betaine) proceeds efficiently (Ashraf and Foolad, 2007 ; Gill and Tuteja, 2010; Hasanuzzaman et al ., 2018). The coordinated induction of these systems enhances ROS buffering, osmotic adjustment, and cellular stability, thereby supporting successful germination and early seedling establishment under saline conditions. Selenium responses in plants follow a classic hormetic dose–response pattern. At low to moderate concentrations, selenium enhances antioxidant capacity, stabilizes redox signaling, and improves growth and stress tolerance [Khan et al., 2023 ; Hussain et al., 2023 ]. However, at higher concentrations, selenium becomes toxic due to its chemical similarity to sulfur, resulting in nonspecific substitution in amino acids, aberrant selenoprotein formation, protein misfolding, and secondary ROS generation (Terry et al., 2000 ; White, 2016 ; Hasanuzzaman et al., 2020 ). This dual behavior explains the narrow beneficial concentration range of selenium and underscores the importance of optimizing priming regimes (El-Badri et al ., 2022). Collectively, this molecular framework links stress perception, selenium-mediated redox regulation, transcriptional control, and protein expression into a coherent model of salinity stress adaptation. By stabilizing early signaling events, protecting redox-sensitive transcription factors, and ensuring effective expression of protective proteins, selenium priming prepares plants for improved physiological and biochemical performance under saline conditions. This conceptual basis provides a foundation for interpreting the germination, growth, and biochemical responses observed in the present study. Germination Germination of Arachis hypogaea was progressively inhibited by increasing salinity but improved in a selenium concentration- and duration-dependent manner. In non-primed seeds, germination remained relatively high under non-saline and mildly saline conditions (0–1.5 g L⁻¹ NaCl; 66.7 ± 3.3%) but declined sharply at higher salinity levels, reaching 53.3 ± 2.1% at 3.5 g L⁻¹, 40.0 ± 2.5% at 5 g L⁻¹, and only 13.3 ± 1.5% at 7 g L⁻¹ NaCl (p < 0.05). This confirms the salt sensitivity of the landrace and aligns with the well-established vulnerability of germination to osmotic stress, delayed imbibition, and early ionic toxicity (Munns and Tester, 2008 ; Ibrahim, 2016). Comparable declines have been reported in wheat ( Triticum aestivum ) and tomato ( Solanum lycopersicum ), where salinity restricts water uptake and disrupts enzymatic reserve mobilization (Iqbal et al., 2015 ; Ashraf et al., 2018 ). Selenium hydropriming significantly improved germination under moderate to severe salinity (p < 0.05), with the most consistent benefits observed at intermediate concentrations (2.5–5 mg L⁻¹). This pattern reflects selenium hormesis, whereby optimal doses enhance stress tolerance via antioxidant activation and metabolic priming, whereas excessive doses exert inhibitory effects (Feng et al., 2013 ; Hasanuzzaman et al., 2020 ). Under non-saline or mildly saline conditions (0–1.5 g L⁻¹ NaCl), priming produced no statistically significant enhancement (p > 0.05), although modest upward trends suggested subtle stimulation of early metabolic readiness (Hasanuzzaman et al ., 2010). Prolonged exposure to higher selenium concentrations occasionally suppressed germination, consistent with interference in germination metabolism at supra-optimal levels (Van Hoewyk, 2013 ). The most pronounced benefits were observed at moderate salinity (3.5–5 g L⁻¹ NaCl), where 6 h priming at 2.5 mg L⁻¹ Se restored germination to 73.3 ± 2.8%, significantly outperforming controls (p < 0.05). This recovery likely reflects improved osmotic adjustment and facilitation of radicle protrusion (Djanaguiraman et al., 2005 ). Under severe salinity (7 g L⁻¹ NaCl), germination of non-primed seeds was severely restricted (13.3 ± 1.5%), whereas the same priming regime induced a marked recovery to 60.0 ± 3.0% (p < 0.05; approximately 4.5-fold increase). This response may be attributed to improved ionic homeostasis, membrane stability, and ROS detoxification during metabolic reactivation (Ulhassan et al., 2019 ; White, 2016 ). Higher selenium concentration (10 mg L⁻¹) was less effective under extreme stress, reinforcing the narrow beneficial threshold (Van Hoewyk, 2013 ). These findings are consistent with reports in rice ( Oryza sativa ), maize ( Zea mays ), and rapeseed ( Brassica napus ), where intermediate selenium doses alleviate salt-induced germination inhibition through enhanced selenoprotein-mediated ROS scavenging and improved water relations (Hasanuzzaman et al ., 2010; Feng et al., 2013 ) (Hussain et al. 2023 ; El-Badri et al . 2022). The consistent optimality of 6 h priming at 2.5 mg L⁻¹ Se across salinity gradients suggests a balanced kinetic window for selenium uptake without toxic overload. Radicle Elongation Radicle emergence and elongation—critical determinants of early seedling establishment—were highly sensitive to salinity stress. In non-primed Arachis hypogaea seedlings, radicle length remained stable under low salinity (0–1.5 g L⁻¹ NaCl; 1.88 ± 0.10 cm), declined modestly at 3.5 g L⁻¹ (1.85 ± 0.12 cm; p < 0.05), and was completely inhibited at ≥ 5 g L⁻¹ NaCl. Selenium hydropriming significantly modulated radicle growth (p < 0.05), enhancing elongation under non-stress conditions at lower to intermediate concentrations and enabling residual growth under severe salinity. Under non-saline conditions, priming for 3 or 9 h at 5 mg L⁻¹ Se increased radicle length to 2.80 ± 0.15 cm (approximately 49% above control), likely through selenium-induced activation of antioxidant defenses and hormone signaling pathways (auxin and gibberellins) that promote cell division and elongation in the root apex (Djanaguiraman et al., 2005 ; Hasanuzzaman et al ., 2010). In contrast, priming with 10 mg L⁻¹ Se caused a duration-dependent reduction in radicle length, reaching 0.80 ± 0.05 cm after 9 h (p < 0.05), indicative of selenium toxicity disrupting sulfur metabolism or inducing secondary oxidative stress (Van Hoewyk, 2013 ). At low salinity (1.5 g L⁻¹ NaCl), priming at lower selenium concentrations produced modest enhancement, with 3 h at 1.5 mg L⁻¹ Se yielding radicles of approximately 2.10 cm, whereas higher concentrations resulted in reductions, reinforcing concentration-specific boundaries. At moderate salinity (3.5 g L⁻¹ NaCl), priming with 2.5 mg L⁻¹ Se for 6 h preserved radicle elongation (2.00 ± 0.12 cm), likely through improved ionic balance and ROS scavenging (Ulhassan et al., 2019 ; Rady et al., 2020 ). Under severe salinity (5–7 g L⁻¹ NaCl), where control seedlings exhibited no radicle growth, selenium priming restored residual elongation. The strongest responses were observed at 6 h priming with 2.5 mg L⁻¹ Se (2.10 ± 0.15 cm at 5 g L⁻¹ NaCl) and 3 h priming with 5 mg L⁻¹ Se (1.60 ± 0.10 cm at 7 g L⁻¹ NaCl). This shift toward slightly higher selenium concentrations under extreme stress may reflect enhanced osmoprotection mediated by proline and other compatible solutes (Jiang et al., 2017 ; García-Locascio et al. 2024 ). Comparable protective effects of selenium on root elongation under salinity have been reported in wheat, rapeseed, and tomato (Ashraf and Foolad, 2007 ; Rady et al., 2020 ). From an agronomic perspective, restoration of radicle elongation under otherwise lethal salinity has direct implications for crop establishment, as deeper and more vigorous roots improve water and nutrient acquisition in saline soils that dominate large agricultural areas globally (Qadir et al., 2014 ; FAO, 2024). These findings position selenium hydro priming as a promising, low-cost strategy for enhancing peanut establishment in marginal environments, provided that concentration and duration are carefully optimized to avoid toxicity (Cunha et al., 2022 ). Shoot Elongation Shoot growth is a sensitive indicator of early seedling vigor and is particularly vulnerable to salinity stress, which suppresses elongation through reduced cellular turgor, disruption of auxin transport, and oxidative damage to meristematic tissues (Munns and Tester, 2008 ; Julkowska and Testerink, 2015 ). In the present study, shoot length was more sensitive to salt stress than radicle elongation. Non-primed seedlings attained 2.95 ± 0.15 cm at low salinity (1.5 g/L NaCl), remained relatively stable at moderate salinity (2.70 ± 0.30 cm at 3.5 g/L NaCl), but were completely inhibited at severe salinity (≥ 5 g/L NaCl). Selenium (Se) hydropriming significantly enhanced shoot elongation in a concentration- and duration-dependent manner (p < 0.05), particularly under non-saline conditions. Priming for 9 h at 1.5–2.5 mg/L Se increased shoot length by up to 45%, reaching 3.70 ± 0.35 cm and 3.60 ± 0.40 cm, respectively. In contrast, priming at 10 mg/L Se resulted in reduced shoot growth, with maximal elongation observed after 3 h (3.10 ± 0.45 cm) followed by a progressive decline with longer durations (2.00 ± 0.50 cm at 9 h), reflecting emerging Se toxicity, likely associated with excessive reactive oxygen species (ROS) accumulation or disruption of sulfur metabolism (Van Hoewyk, 2013 ). At low salinity (1.5 g/L NaCl), shoot height of primed seedlings did not differ significantly from controls. Under moderate salinity (3.5 g/L NaCl), 6 h priming at 2.5 mg/L Se effectively maintained shoot elongation (2.80 ± 0.30 cm), likely through improved Na⁺ exclusion and K⁺ retention, thereby sustaining turgor pressure (Rady et al., 2020 ). However, higher Se concentrations (5–10 mg/L), especially under severe salinity (≥ 5 g/L NaCl), resulted in a consistent decline in shoot height with increasing priming duration, indicating combined Se–salinity toxicity. Overall, 1.5–2.5 mg/L Se best preserved shoot elongation, with 6 h priming at 2.5 mg/L emerging as the optimal treatment. Residual shoot growth observed at higher Se concentrations under severe salinity may reflect partial mitigation of Na⁺ toxicity via enhanced ion compartmentation or osmotic adjustment, although batch-to-batch variability cannot be excluded. Leaflet Development Salinity progressively impaired leaflet initiation in Arachis hypogaea seedlings. Non-primed controls maintained 11.0 ± 1.0 leaflets under non-saline conditions, increased slightly at low salinity (13.3 ± 1.2 at 1.5 g/L NaCl), declined at moderate salinity (10.7 ± 2.0 at 3.5 g/L NaCl; p < 0.05), and were completely suppressed at severe salinity (≥ 5 g/L NaCl). This trend reflects the combined osmotic and ionic effects of salinity on meristematic activity and hormonal balance, ultimately restricting leaf primordia formation (Munns and Tester, 2008 ; Julkowska and Testerink, 2015 ). Under non-saline conditions, Se priming at 1.5–5 mg/L markedly enhanced leaflet production. The best response occurred with 9 h priming at 1.5 mg/L Se (17.5 ± 1.5 leaflets), representing a > 59% increase over controls. This enhancement likely results from Se-mediated stimulation of cytokinin signaling and auxin transport, promoting cell division in the shoot apical meristem (Hasanuzzaman et al ., 2010; Zhu et al ., 2017; Khan et al., 2023 ). Longer priming durations (6–9 h) were generally more effective at lower Se concentrations, allowing sufficient Se uptake without inducing toxicity. In contrast, 10 mg/L Se significantly reduced leaflet number, with 9 h priming yielding only 8.0 ± 2.5 leaflets, indicative of inhibitory effects associated with oxidative and metabolic disruption (Van Hoewyk, 2013 ;Hussain et al., 2023 ). At moderate salinity (3.5 g/L NaCl), lower Se concentrations (1.5–2.5 mg/L) preserved or slightly enhanced leaflet numbers, with 6 h priming at 2.5 mg/L Se producing 12.5 ± 1.5 leaflets. This retention suggests Se-mediated mitigation of ionic imbalance and maintenance of hormonal homeostasis required for leaf initiation (Rady et al., 2020 ). Higher Se concentrations (5–10 mg/L) significantly reduced leaflet number (p < 0.05), highlighting the narrow margin between Se benefit and toxicity. Under severe salinity (5 g/L NaCl), Se priming enabled partial recovery of leaflet development, with the best response observed at 6 h priming with 5 mg/L Se (4.0 ± 0.8 leaflets), followed by 6 h at 10 mg/L Se (3.0 ± 1.0 leaflets). This partial rescue likely reflects enhanced ROS detoxification and osmoprotectant synthesis, sustaining minimal meristematic activity under extreme stress (Ulhassan et al., 2019 ;García-Locascio et al., 2024 ). No leaflet formation occurred at 7 g/L NaCl across treatments, indicating an upper limit to Se-mediated protection. Chlorophyll Content Chlorophyll content, a sensitive indicator of photosynthetic capacity and oxidative stress tolerance, responded strongly to Se priming under salinity stress. Under non-saline conditions, priming with 1.5–5 mg/L Se significantly increased chlorophyll content, with the highest value (2.51 ± 0.03 mg/g FW) recorded after 6 h priming at 5 mg/L Se—a 34% increase over controls. This enhancement likely reflects Se’s antioxidant role in reducing ROS and stabilizing chloroplast membranes, possibly through modulation of chlorophyll biosynthesis pathways (Feng et al., 2013 ;Cunha et al., 2022 ). In contrast, high Se concentration (10 mg/L) reduced chlorophyll content across durations, with 9 h priming yielding only 1.08 ± 0.02 mg/g FW, indicative of phytotoxicity associated with excessive seleno-amino acid incorporation or sulfur metabolic disruption (Van Hoewyk, 2013 ). As salinity intensified, Se’s protective effects became more evident under moderate stress but insufficient under extreme conditions. At 3.5 g/L NaCl, 3 h priming at 1.5 mg/L Se retained the highest chlorophyll content (1.75 ± 0.08 mg/g FW), representing a 50% improvement over controls, likely through enhanced antioxidant enzyme activity and preservation of chloroplast integrity (Rady et al., 2020 ). Under severe salinity (5 g/L NaCl), residual chlorophyll was detectable only in primed seedlings, with 6 h priming at 5 mg/L Se producing the highest retention (0.49 ± 0.05 mg/g FW). No chlorophyll was detectable at 7 g/L NaCl, marking the threshold beyond which Se protection failed. Proline Accumulation Proline accumulation is a hallmark of plant responses to salinity stress, contributing to osmotic adjustment, protein stabilization, and ROS scavenging (Szabados and Savouré, 2010 ). Selenium priming significantly modulated proline content in a concentration- and duration-dependent manner. Under non-saline and low-salinity conditions (0–1.5 g/L NaCl), low to intermediate Se concentrations (1.5–5 mg/L) caused only modest increases in proline relative to controls, remaining well below stress-induced levels and reflecting metabolic priming rather than stress perception. In contrast, 10 mg/L Se induced pronounced proline accumulation even in the absence of salt stress (up to 92.0 ± 4.0 µmol/g FW after 9 h), suggesting that high Se acted as a mild stressor, activating osmolyte synthesis pathways similar to responses observed in Se-hyperaccumulator species (Freeman et al., 2006 ). At moderate salinity (3.5 g/L NaCl), Se priming synergistically enhanced proline accumulation, particularly with longer priming durations. For instance, 9 h priming at 5 mg/L Se increased proline to 127.0 ± 5.0 µmol/g FW (74% above control), supporting improved osmotic adjustment. However, 10 mg/L Se triggered extreme accumulation (260.0 ± 8.0 µmol/g FW), approaching levels associated with metabolic imbalance (Verbruggen and Hermans, 2008 ; El-Badri et al ., 2022). Under severe salinity (≥ 5 g/L NaCl), unprimed seedlings showed no detectable proline, whereas Se priming enabled substantial accumulation. At 5 g/L NaCl, 9 h priming at 5 mg/L Se yielded 200.0 ± 8.5 µmol/g FW, while 10 mg/L Se reached 290.0 ± 7.5 µmol/g FW. At 7 g/L NaCl, maximal accumulation (320.0 ± 9.0 µmol/g FW) occurred with 9 h priming at 10 mg/L Se, reflecting a compensatory response to combined Se and salinity stress (Hasanuzzaman et al., 2014 ; Ulhassan et al., 2019 ). Seedling Dry Weight Seedling dry weight, an integrative measure of biomass accumulation and overall vigor, was strongly influenced by Se priming under salinity stress. In non-primed controls, dry weight remained relatively stable under low to moderate salinity (0.094–0.117 g at 0–3.5 g/L NaCl) but declined to zero at ≥ 5 g/L NaCl, indicating failure of seedling establishment due to osmotic shock and ionic toxicity (Munns and Tester, 2008 ). At low salinity (1.5 g/L NaCl), Se priming significantly enhanced biomass accumulation, with 6 h priming at 5 mg/L Se producing 0.185 ± 0.018 g, over 60% higher than controls. This response highlights an optimal Se uptake window that balances antioxidant protection with growth promotion (Rady et al., 2020 ) (Cunha et al. 2022 ). Under moderate salinity (3.5 g/L NaCl), intermediate Se concentrations maintained or slightly increased dry weight, with 6 h priming at 5 mg/L Se yielding 0.135 ± 0.018 g. In contrast, 10 mg/L Se produced neutral or inhibitory effects, consistent with early toxicity symptoms. At severe salinity (≥ 5 g/L NaCl), Se priming enabled residual biomass accumulation where unprimed seedlings failed. At 5 g/L NaCl, 6 h priming at 2.5–5 mg/L Se resulted in ~ 0.110 g dry weight, while at 7 g/L NaCl, the highest value (0.050 ± 0.012 g) occurred with 6 h priming at 2.5 mg/L Se. This shift toward lower Se under extreme stress suggests a trade-off between osmoprotection and metabolic cost, emphasizing the narrow margin of Se efficacy under lethal salinity (Jiang et al., 2017 ; Ulhassan et al., 2019 ). Composite z-score Selenium priming exerted a clear influence on overall seedling performance across salinity gradients, as reflected by composite z-scores integrating all measured parameters. Under non-saline conditions (0 g/L NaCl), priming with 1.5 mg/L Se for 6 h produced the highest composite score (1.193). At this low Se dose, seedlings likely benefited from enhanced chlorophyll retention and improved basal metabolic activity, supporting efficient photosynthesis, energy production, and early growth without imposing metabolic costs (Hasanuzzaman et al., 2020 ; Khan et al., 2023 ). This response suggests that low-dose Se primes cellular metabolism through selenoprotein-mediated reactive oxygen species (ROS) scavenging and modulation of growth-related hormonal signaling pathways. At mild salinity (1.5 g/L NaCl), the optimal treatment shifted to 5 mg/L Se for 6 h, yielding a composite score of 1.045. This shift indicates an increased Se requirement under osmotic stress, where intermediate Se concentrations likely enhanced antioxidant defenses, improved water relations, and sustained nutrient acquisition (Hussain et al., 2023 . Consequently, seedlings maintained relatively higher chlorophyll content and overall vigor compared with other treatments. Under moderate salinity (3.5 g/L NaCl), priming with 2.5 mg/L Se for 6 h produced the highest composite score (0.692), suggesting an optimal balance between selenium’s protective effects and the onset of toxicity at higher concentrations. Similar dose-dependent responses to Se under salt stress have been reported in other crops (Hawrylak-Nowak et al ., 2014; Ziegler & Fageria, 2021 ). At higher salinity levels (5–7 g/L NaCl), the best-performing treatments also involved 2.5 mg/L Se; however, composite scores were negative (− 0.431 at 5 g/L and − 0.611 at 7 g/L). These negative values indicate that overall seedling performance was severely constrained by extreme salinity. Nevertheless, the selected Se treatments still conferred relative advantages by increasing germination rate, sustaining residual chlorophyll content and metabolic activity, reflecting a narrow balance between selenium-mediated osmotic and oxidative protection and avoidance of supra-optimal toxicity (García-Locascio et al., 2024 ). Overall, the composite z-score analysis demonstrates that selenium priming modulates seedling performance in a dose- and stress-dependent manner. Positive z-scores identify treatments that optimize integrated physiological performance, whereas negative values highlight conditions under which seedlings remain constrained but still respond most favorably to specific selenium regimes. These findings underscore the importance of carefully matching selenium dose and stress intensity when interpreting in vitro responses, without extrapolating directly to field performance. Conclusion This study demonstrates that selenium hydro-priming enhances early seedling establishment of Arachis hypogaea under saline conditions, primarily by accelerating germination and promoting radicle development. Seedling survival under salinity was driven more by enhanced germination and early root growth than by later biomass accumulation, highlighting the importance of rapid establishment in stress-prone environments. Across salinity levels, low to intermediate selenium concentrations combined with short to intermediate priming durations consistently produced the most favorable responses, reflecting selenium’s hormetic behavior. From these results, sweet spots for selenium priming can be identified: a priming duration of 6 h consistently produced the highest composite z-scores across different salt levels, while the optimal selenium concentration depended on salt stress: 1.5 mg/L for 0 g/L, 5 mg/L for 1.5 g/L, and 2.5 mg/L for 3.5–7 g/L. These patterns indicate that selenium can enhance relative seedling performance in vitro by supporting chlorophyll content and metabolic processes, even under increasing salt stress. Negative z-scores highlight the constraints imposed by high salinity, but the treatments identified as optimal consistently produced the highest relative composite performance, emphasizing the importance of selenium dose and priming duration in moderating salt stress effects. While these findings provide strong physiological evidence for the effectiveness of selenium hydropriming, field-based validation under variable soil and environmental conditions is required to confirm the consistency, scalability, and agronomic relevance of this approach. Overall, selenium hydropriming represents a practical, low-cost strategy for improving the establishment of Arachis hypogaea landraces in saline soils, provided that concentration and exposure time are carefully optimized. Abbreviations Se Selenium NaCl Sodium chloride SD Standard deviation h Hour(s) mg/L Milligrams per liter g/l Grams per liter cm Centimeter mg g − 1 FW Milligram per gram Fresh Weight µmol g − 1 FW Micromoles per Gram Fresh Weight ZISCO Composite z-score index ROS Reactive oxygen species MGT Mean Germination Time GV Germination Velocity GRI Germination Rate Index Declarations Ethics and Consent to participate: The plant material ( Arachis hypogeal L .) used in this study was cultivated under standard agronomic practices in, Etsako West Local Government Area, Edo State, Nigeria. All procedures complied with local and national guidelines for the use of the cultivated plant material. No wide or endanger species were used and no specific permission or license were required. Consent to publish: Not applicable. Availability of data and material : All data generated or analyzed are included in this manuscript except for the germination indices MGT, GV and GRI, for sake of convenience have been placed as supplementary data. Competing interests : The authors declare no competing interests. Funding : This work was personally funded by the authors; no external funding was received. Author’s contributions : Conceptualization : Eromosele Noble Isibor Methodology : Eromosele Noble Isibor; Boniface Edegbai. Formal Analysis and investigation : Eromosele Noble Isibor. Writing-Review and editing : Rida Batool; Ifie Etumah Sandra. Eromosele Noble Isibor Supervision : Eromosele Noble Isibor; Boniface Edegbai; Beckley Ikhajiagbe Acknowledgments : I will like to appreciate Happy and Christopher, undergraduate students of the department of Science Laboratory Technology, Faculty of Life Sciences, University of Benin for their assistance in data collection. Also Mrs. Enabele, Chief laboratory officer at the department of Plant Biology and Biotechnology for granting us access to the lab for the experiment. References Abbas, G., Iqbal, N., Ali, S., et al. Effects of salinity on germination and seedling growth of groundnut ( Arachis hypogaea L .). Pak. J. Bot. 47, 123–132 (2015). Arnon, D. I. Copper enzymes in isolated chloroplasts. Polyphenoloxidase in Beta vulgaris . Plant Physiol. 24, 1–15 (1949). Ashraf, M. &Foolad, M. R. Roles of glycine betaine and proline in improving plant abiotic stress resistance. Environ. Exp. Bot. 59, 206–216 (2007). Ashraf, M., Foolad, M. R., Iqbal, N., et al. Seed priming: physiological basis and applications. J. Integr. Plant Biol. 60, 598–612 (2018). Astaneh, F., Shabani, L., &Rezaei, A. Selenium priming alleviates oxidative stress under salinity in tomato seedlings. J. Plant Nutr. 41, 1234–1245 (2018). Bates, L. S., Waldren, R. P., &Teare, I. D. Rapid determination of free proline for water-stress studies. Plant Soil 39, 205–207 (1973). Chowdhury, M. A. H., Bhuiyan, M. S. R., Shah-E-Alam, M., et al. Evaluation of combining ability and genetic analysis for salinity tolerance in a 7 × 7 F1 half-diallel population of groundnut ( Arachis hypogaea L .). Discov. Plants 2, 327 (2025). Cunha, M. L. O., de Oliveira, L. C. A., Silva, V. M., Montanha, G. S., & Dos Reis, A. R. Selenium increases photosynthetic capacity, daidzein biosynthesis, nodulation and yield of peanut plants ( Arachis hypogaea L .). Plant Physiol. Biochem. 190, 231–239 (2022). D’Autréaux, B. &Toledano, M. B. ROS as signalling molecules: mechanisms that generate specificity in ROS homeostasis. Nat. Rev. Mol. Cell Biol. 8, 813–824 (2007). Dietz, K. J. Redox signal integration: from stimulus to networks and genes. Physiol. Plant. 151, 392–405 (2014). Djanaguiraman, M., Devi, D. N., Sheeba, J. A., et al. Selenium protects peanut seedlings from oxidative stress under salinity. Plant Physiol. Biochem. 43, 569–577 (2005). El-Badri, A. M., Batool, M., Mohamed, I. A. A., Wang, Z., Wang, C., Tabl, K. M., et al. Mitigation of the salinity stress in rapeseed ( Brassica napus L .) productivity by exogenous applications of bio-selenium nanoparticles during the early seedling stage. Environ. Pollut. 310, 119815 (2022a). FAO. The State of Food and Agriculture 2021: Making Agrifood Systems More Resilient. Food and Agriculture Organization, Rome (2021). Feng, R., Wei, C., &Tu, S. The roles of selenium in protecting plants against abiotic stresses. Environ. Exp. Bot. 87, 58–68 (2013). Freeman, J. L., Zhang, L., Marcus, M. A., et al. Spatial imaging, speciation, and quantification of selenium in Stanleyapinnata plant tissue by X-ray absorption spectroscopy. Plant Physiol. 142, 124–134 (2006). Gill, S. S. &Tuteja, N. Reactive oxygen species and antioxidant machinery in abiotic stress tolerance in crop plants. Plant Physiol. Biochem. 48, 909–930 (2010). García-Locascio, E., Valenzuela, E. I., & Cervantes-Avilés, P. Impact of seed priming with selenium nanoparticles on germination and seedlings growth of tomato. Sci. Rep. 14, 6726 (2024). Hasanuzzaman, M., Bhuyan, M. H. M. B., Zulfiqar, F., et al. Reactive oxygen species and antioxidant defense in plants under abiotic stress: revisiting the role of selenium. Biol. Trace Elem. Res. 199, 1–35 (2020). Hasanuzzaman, M., Nahar, K., Alam, M. M., et al. Physiological, biochemical, and molecular mechanisms of selenium-induced stress tolerance in plants. Front. Plant Sci. 5, 355 (2014). Hawrylak-Nowak, B. Selenium-mediated growth and stress tolerance in plants. Acta Physiol. Plant. 36, 2311–2319 (2014). Hawrylak-Nowak, B. Selenium-induced changes in growth and antioxidant system of cucumber seedlings. Biol. Plant. 53, 541–545 (2009). Hussain, S., Ahmed, S., Akram, W., Li, G., &Yasin, N. A. Selenium seed priming enhanced the growth of salt-stressed Brassica rapa L . through improving plant nutrition and the antioxidant system. Front. Plant Sci. 13, 1050359 (2023). IPCC. Climate Change 2022: Impacts, Adaptation and Vulnerability. Intergovernmental Panel on Climate Change, Geneva (2022). Iqbal, M., Ashraf, M., & Jamil, A. Alleviation of salt stress in tomato ( Solanum lycopersicum ) by selenium and proline. Pak. J. Bot. 47, 45–54 (2015). Jiang, C., Ma, L., et al. Selenium enhances salt tolerance in plants through modulation of proline metabolism and antioxidative defense. Plant Soil 418, 345–360 (2017). Julkowska, M. M. &Testerink, C. Tuning plant signaling and growth to survive salt. Trends Plant Sci. 20, 586–594 (2015). Khan, Z., Thounaojam, T. C., Chowdhury, D., &Upadhyaya, H. The role of selenium and nano selenium on physiological responses in plant: a review. Plant Growth Regul. 100, 409–433 (2023). Mensah, J. T., Oppong, S., &Osei, M. Effects of salinity on groundnut germination and early growth. Int. J. Agric. Biol. 8, 857–861 (2006). Munns, R. & Tester, M. Mechanisms of salinity tolerance. Annu. Rev. Plant Biol. 59, 651–681 (2008). Pilon-Smits, E. A. & Quinn, C. F. Selenium metabolism in plants and its impact on stress tolerance. J. Plant Nutr. 33, 1245–1260 (2010). Pilon-Smits, E. A., Quinn, C. F., & Schiavon, M. Selenium metabolism in plants. Plant Sci. 196, 1–12 (2009). Qadir, M., Quillérou, E., Nangia, V., et al. Economics of salt-induced land degradation and restoration. Nat. Resour. Forum 38, 282–295 (2014). Rady, M. M., Hemida, K. A., &Hemida, S. Selenium and salt stress interactions in crop plants: effects on growth and physiology. Environ. Sci. Pollut. Res. 27, 3456–3470 (2020). Rios, J. J., Gallardo, M., & Romero, L. Selenium modulates proline metabolism in Brassica species under stress. Plant Physiol. Biochem. 46, 497–503 (2008). Schiavon, M. &Pilon-Smits, E. A. Selenium in plants: understanding the dual nature of Se for plant physiology and human nutrition. Front. Plant Sci. 8, 978 (2017). Schiavon, M., Pilon-Smits, E., &Wangeline, A. J. Selenium biofortification: uptake, metabolism, and benefits in plants. Plant Biol. 18, 1–10 (2016). Sors, T. G., Ellis, D. R., & Salt, D. E. Selenium uptake, translocation, assimilation, and metabolic fate in plants. Photosynth. Res. 86, 373–389 (2005). Szabados, L. &Savouré, A. Proline: a multifunctional amino acid. Trends Plant Sci. 15, 89–97 (2010). Terry, N., Zayed, A. M., de Souza, M. P., &Tarun, A. S. Selenium in higher plants. Annu. Rev. Plant Physiol. Plant Mol. Biol. 51, 401–432 (2000). Ulhassan, Z., Ashraf, M., & Ali, S. Selenium priming improves salinity tolerance in rice seedlings. Plant Physiol. Biochem. 145, 31–41 (2019). Upadhyaya, H. D., Bramel, P. J., Singh, S., & Ortiz, R. Developing groundnut cultivars for marginal environments: advances and challenges. Crop Sci. 54, 1243–1253 (2014). Van Hoewyk, D. Selenium-induced stress and toxicity in plants. Physiol. Plant. 149, 725–739 (2013). Verbruggen, N. &Hermans, C. Proline accumulation in plants: a review. Plant Biol. 10, 305–320 (2008). White, P. J. Selenium accumulation and metabolism in plants: consequences for human health. J. Exp. Bot. 67, 3703–3715 (2016). Ziegler, J. & Fageria, N. K. Seed priming strategies for enhanced stress tolerance in crops: a review. Agron. J. 113, 1–15 (2021). Zhu, J. K. Plant salt tolerance. Trends Plant Sci. 6, 66–71 (2001). Zhu, J. K. Regulation of ion homeostasis under salt stress. Curr. Opin. Plant Biol. 5, 441–445 (2002). Additional Declarations No competing interests reported. Supplementary Files EMS1.docx Cite Share Download PDF Status: Under Review Version 1 posted Editorial decision: Revision requested 30 Mar, 2026 Reviews received at journal 08 Mar, 2026 Reviews received at journal 07 Mar, 2026 Reviews received at journal 03 Mar, 2026 Reviews received at journal 02 Mar, 2026 Reviewers agreed at journal 28 Feb, 2026 Reviewers agreed at journal 28 Feb, 2026 Reviewers agreed at journal 27 Feb, 2026 Reviewers agreed at journal 26 Feb, 2026 Reviews received at journal 23 Feb, 2026 Reviewers agreed at journal 16 Feb, 2026 Reviewers agreed at journal 07 Feb, 2026 Reviewers invited by journal 05 Feb, 2026 Editor invited by journal 23 Jan, 2026 Editor assigned by journal 22 Jan, 2026 Submission checks completed at journal 22 Jan, 2026 First submitted to journal 22 Jan, 2026 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-8605366","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":587545026,"identity":"62f7e178-0b45-4993-b82e-7971f5e54d07","order_by":0,"name":"Eromosele Noble Isibor¹","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA1UlEQVRIiWNgGAWjYFACHsYDDAY1PGzsDUCOgQVRWhgOMBQck+HjOQDSIkGslg/MNnISCSAeEVrM2XsPHOYxYONhk3x+dcOPAgkG/vbuBLxaLHvOJQC1yPCwSeeU3ewBOkzizNkNeLUY3MgxgNginZN2gweoxUAilygtzECHnUm7+Yc0LRLsx24TZ8uZcwkH5xgc42HjyWG7LWMgwUPYL8d7Dz5486fGXr79+LObb/7YyPG39+LXAgJMPGCKxwBMElQOAow/wBT7A6JUj4JRMApGwcgDALf0RJ5HhMtGAAAAAElFTkSuQmCC","orcid":"","institution":"University of Benin","correspondingAuthor":true,"prefix":"","firstName":"Eromosele","middleName":"Noble","lastName":"Isibor¹","suffix":""},{"id":587545030,"identity":"4abcd4ec-be9a-4e21-80a8-10c22d04a969","order_by":1,"name":"Rida Batool²","email":"","orcid":"","institution":"Quaid-i-Azam University, Islamabad,","correspondingAuthor":false,"prefix":"","firstName":"Rida","middleName":"","lastName":"Batool²","suffix":""},{"id":587545035,"identity":"aa83b2d2-977b-43eb-9f1c-906af581d99c","order_by":2,"name":"Boniface Edegbai³","email":"","orcid":"","institution":"University of Benin","correspondingAuthor":false,"prefix":"","firstName":"Boniface","middleName":"","lastName":"Edegbai³","suffix":""},{"id":587545040,"identity":"3e84db1a-8119-44d2-9140-f0a3b91020dd","order_by":3,"name":"Ifie Etumah Sandra","email":"","orcid":"","institution":"Kampala International University","correspondingAuthor":false,"prefix":"","firstName":"Ifie","middleName":"Etumah","lastName":"Sandra","suffix":""},{"id":587545045,"identity":"acdc2706-6451-42c0-81e1-47175e4bf700","order_by":4,"name":"Beckley Ikhajiagbe","email":"","orcid":"","institution":"University of Benin","correspondingAuthor":false,"prefix":"","firstName":"Beckley","middleName":"","lastName":"Ikhajiagbe","suffix":""}],"badges":[],"createdAt":"2026-01-14 22:38:20","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-8605366/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-8605366/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":102325650,"identity":"085d5b70-7fbc-442d-b04a-4434a8692a10","added_by":"auto","created_at":"2026-02-10 14:26:49","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":10880,"visible":true,"origin":"","legend":"\u003cp\u003eGermination percentage (%) of Auchi groundnut, a landrace of \u003cem\u003eArachis hypogaea L\u003c/em\u003e., pretreated at different selenium (Se) durations ( 3h, 6h, 9h) and exposed to increasing salinity levels (0, 1.5, 3.5, 5, and 7 g/L NaCl). Panels represent Se pretreatment concentrations of (a) 1.5 mg/L, (b) 2.5 mg/L, (c) 5 mg/L, and (d) 10 mg/L. Final germination percentage was determined after 10 days of sowing. Error bars represent ± SD (n = 3). Different lowercase letters indicate significant differences among treatments within each salt concentration (p \u0026lt; 0.05; Tukey’s test).\u003c/p\u003e","description":"","filename":"Onlinefloatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-8605366/v1/c9dbc65f644211dccb89e2ca.png"},{"id":102325652,"identity":"ed810a93-801b-4faa-83aa-4a99b899c7ac","added_by":"auto","created_at":"2026-02-10 14:26:49","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":11872,"visible":true,"origin":"","legend":"\u003cp\u003eRadicle length (cm) of seedlings of Auchi groundnut, a landrace of \u003cem\u003eArachis hypogaea\u003c/em\u003e \u003cem\u003eL\u003c/em\u003e., pretreated with different of selenium (Se) durations ( 3h, 6h, 9h) and grown under varying salt concentrations (0, 1.5, 3.5, 5, and 7 g/L NaCl). Panels correspond to Se pretreatment concentrations of (a) 1.5 mg/L, (b) 2.5 mg/L, (c) 5 mg/L, and (d) 10 mg/L. Radicle length was measured 10 days after sowing. Error bars represent ± SD (n = 3). Different lowercase letters denote significant differences among treatments within each salt concentration (p \u0026lt; 0.05; Tukey’s test).\u003c/p\u003e","description":"","filename":"Onlinefloatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-8605366/v1/da9b6937af9d0a5ba0777a23.png"},{"id":102325648,"identity":"6649f565-1660-4828-bc77-941cb980eefa","added_by":"auto","created_at":"2026-02-10 14:26:49","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":10964,"visible":true,"origin":"","legend":"\u003cp\u003eShoot length (cm) of seedlings of Auchi groundnut, a landrace of \u003cem\u003eArachis hypogaea L\u003c/em\u003e., pretreated with different durations of selenium (Se) ( 3h, 6h, 9h) and subjected to increasing salinity levels (0, 1.5, 3.5, 5, and 7 g/L NaCl). Panels represent Se pretreatment concentrations of (a) 1.5 mg/L, (b) 2.5 mg/L, (c) 5 mg/L, and (d) 10 mg/L. Shoot length was measured 10 days after sowing. Error bars represent ± SD (n = 3). Different lowercase letters indicate significant differences among treatments within each salt concentration (p \u0026lt; 0.05; Tukey’s test).\u003c/p\u003e","description":"","filename":"Onlinefloatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-8605366/v1/b0ce5979a0693d51f146f1f4.png"},{"id":102325666,"identity":"34fb1686-d6c5-4bc4-a015-a8f96cc640f4","added_by":"auto","created_at":"2026-02-10 14:26:59","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":10687,"visible":true,"origin":"","legend":"\u003cp\u003eNumber of leaflets per seedling of Auchi groundnut, a landrace of \u003cem\u003eArachis hypogaea L\u003c/em\u003e., as influenced by selenium (Se) pretreatment duration ( 3h, 6h, 9h) under different salt concentrations (0, 1.5, 3.5, 5, and 7 g/L NaCl). Panels correspond to Se pretreatment concentrations of (a) 1.5 mg/L, (b) 2.5 mg/L, (c) 5 mg/L, and (d) 10 mg/L. Leaflet number was recorded 10 days after sowing. Error bars represent ± SD (n = 3). Different lowercase letters denote significant differences among treatments within each salt concentration (p \u0026lt; 0.05; Tukey’s test).\u003c/p\u003e","description":"","filename":"Onlinefloatimage4.png","url":"https://assets-eu.researchsquare.com/files/rs-8605366/v1/274404fc732b037abfaacced.png"},{"id":102325651,"identity":"aaeddeaa-0930-4796-b8b4-749ab401b6f8","added_by":"auto","created_at":"2026-02-10 14:26:49","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":11636,"visible":true,"origin":"","legend":"\u003cp\u003eTotal chlorophyll content (mg g⁻¹ fresh weight) of seedlings of Auchi groundnut, a landrace of \u003cem\u003eArachis hypogaea L\u003c/em\u003e., pretreated at different selenium (Se) durations ( 3h, 6h, 9h) and exposed to increasing salt stress (0, 1.5, 3.5, 5, and 7 g/L NaCl). Panels represent Se pretreatment concentrations of (a) 1.5 mg/L, (b) 2.5 mg/L, (c) 5 mg/L, and (d) 10 mg/L. Chlorophyll content was determined 10 days after sowing. Error bars represent ± SD (n = 3). Different lowercase letters indicate significant differences among treatments within each salt concentration (p \u0026lt; 0.05; Tukey’s test).\u003c/p\u003e","description":"","filename":"Onlinefloatimage5.png","url":"https://assets-eu.researchsquare.com/files/rs-8605366/v1/7aa42dd0f894e9ab83b62c6c.png"},{"id":102325644,"identity":"33ab04b9-69bf-48cf-b777-aad29a152fc9","added_by":"auto","created_at":"2026-02-10 14:26:47","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":11562,"visible":true,"origin":"","legend":"\u003cp\u003eProline content (µmol g⁻¹ fresh weight) of seedlings of Auchi groundnut, a landrace of \u003cem\u003eArachis hypogaea L\u003c/em\u003e., pretreated with different selenium (Se) durations ( 3h, 6h, 9h) and subjected to increasing salt stress (0, 1.5, 3.5, 5, and 7 g/L NaCl). Panels represent Se pretreatment concentrations of (a) 1.5 mg/L, (b) 2.5 mg/L, (c) 5 mg/L, and (d) 10 mg/L. Proline content was quantified 10 days after sowing. Error bars represent ± SD (n = 3). Different lowercase letters indicate significant differences among treatments within each salt concentration (p \u0026lt; 0.05; Tukey’s test).\u003c/p\u003e","description":"","filename":"Onlinefloatimage6.png","url":"https://assets-eu.researchsquare.com/files/rs-8605366/v1/203d08a9bee6533a76a33fcb.png"},{"id":102325658,"identity":"c5b69196-d132-4d26-8a63-fff3423f850c","added_by":"auto","created_at":"2026-02-10 14:26:58","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":12761,"visible":true,"origin":"","legend":"\u003cp\u003eDry seedling weight (g) of Auchi groundnut, a landrace of \u003cem\u003eArachis hypogaea L\u003c/em\u003e., pretreated with different durations of selenium (Se) ( 3h, 6h, 9h) and grown under varying salinity levels (0, 1.5, 3.5, 5, and 7 g/L NaCl). Panels correspond to Se pretreatment concentrations of (a) 1.5 mg/L, (b) 2.5 mg/L, (c) 5 mg/L, and (d) 10 mg/L. Dry weight was measured 10 days after sowing following oven drying to constant weight. Error bars represent ± SD (n = 3). Different lowercase letters denote significant differences among treatments within each salt concentration (p \u0026lt; 0.05; Tukey’s test).\u003c/p\u003e","description":"","filename":"Onlinefloatimage7.png","url":"https://assets-eu.researchsquare.com/files/rs-8605366/v1/cca27bd985046baec896adc8.png"},{"id":102325656,"identity":"8a706353-bc35-4717-a92f-2f07ad43a976","added_by":"auto","created_at":"2026-02-10 14:26:53","extension":"png","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":6745,"visible":true,"origin":"","legend":"\u003cp\u003eComposite Z-score index (ZISCO) integrating all measured germination, growth, physiological, and biochemical parameters of Auchi groundnut, a landrace of \u003cem\u003eArachis hypogaea\u003c/em\u003e L. The figure compares the best selenium (Se) pretreatment across different salt concentrations (0, 1.5, 3.5, 5, and 7 g/L NaCl), summarizing overall performance under salinity stress.\u003c/p\u003e","description":"","filename":"Onlinefloatimage8.png","url":"https://assets-eu.researchsquare.com/files/rs-8605366/v1/5318e3f3c2d36f47b792cc7f.png"},{"id":105903681,"identity":"9c90fc7c-5c9a-4a56-bef1-ddad54dcc88f","added_by":"auto","created_at":"2026-04-01 09:47:54","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1144543,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8605366/v1/50e46494-e04a-4e83-9cf9-b45983c6f3d4.pdf"},{"id":102325670,"identity":"45b0e9ca-796c-4c76-8704-b5241e4fd232","added_by":"auto","created_at":"2026-02-10 14:27:00","extension":"docx","order_by":0,"title":"","display":"","copyAsset":false,"role":"supplement","size":55591,"visible":true,"origin":"","legend":"","description":"","filename":"EMS1.docx","url":"https://assets-eu.researchsquare.com/files/rs-8605366/v1/3663a5bbdf4c592d3ca5beea.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Effect of Selenium Priming duration on Germination and Early Seedling Development of Arachis hypogaea L. Across a Salinity Gradient","fulltext":[{"header":"INTRODUCTION","content":"\u003cp\u003eSoil salinity is one of the most severe abiotic stresses limiting agricultural production worldwide, particularly in arid and semi-arid regions (Munns and Tester \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e2008\u003c/span\u003e). Global warming associated with climate change has intensified this problem by increasing soil water evaporation and altering rainfall patterns, leading to the accumulation of soluble salts in agricultural soils and the flooding of farmlands in coastal areas with saline water (IPCC 2022). Poor irrigation practices and inadequate drainage systems further exacerbate soil salinization in many developing countries, resulting in reduced crop establishment, growth, and yield, and consequently increasing food insecurity (FAO \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). Salinity is especially detrimental during germination and early seedling development due to osmotic stress, excessive accumulation of sodium and chloride ions, and oxidative damage caused by the overproduction of reactive oxygen species (ROS) (Zhu \u003cspan citationid=\"CR46\" class=\"CitationRef\"\u003e2001\u003c/span\u003e; Hasanuzzaman et al., \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e2014\u003c/span\u003e). These effects disrupt cellular metabolism, enzyme activity, and membrane integrity, ultimately reducing germination efficiency and seedling establishment\u0026mdash;developmental stages that are highly sensitive to osmotic stress and ion toxicity (Zhu \u003cspan citationid=\"CR46\" class=\"CitationRef\"\u003e2001\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eGroundnut (\u003cem\u003eArachis hypogaea L\u003c/em\u003e.) is an economically important legume cultivated extensively for its oil content, protein value, and contribution to household income and food security, particularly in sub-Saharan Africa (Upadhyaya et al., \u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e2014\u003c/span\u003e). However, groundnut is considered moderately to highly sensitive to salinity, with adverse effects reported on germination rate, seedling vigor, and biomass accumulation (Mensah et al., \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e2006\u003c/span\u003e; Abbas et al., \u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e2015\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eIn Nigeria and similar agro-ecological regions where groundnut is cultivated, production relies largely on locally adapted landraces grown by smallholder farmers. These landraces are often preferred for their adaptability and availability but generally lack improved tolerance to increasing soil salinity, making early seedling failure a major constraint to local productivity. Although genetic improvement for salt tolerance represents a desirable long-term solution, it is time-consuming and frequently inaccessible for locally important landraces. Consequently, there is growing interest in low-cost agronomic interventions that enhance early-stage stress tolerance.\u003c/p\u003e \u003cp\u003eSelenium, although not essential for higher plants, has been shown at adequate concentrations to improve ion homeostasis, reduce sodium uptake, and enhance osmotic adjustment, thereby contributing to improved stress resilience (Hawrylak-Nowak \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e2009\u003c/span\u003e). However, selenium exhibits a narrow margin between beneficial and toxic concentrations, and excessive application can impair growth and induce oxidative stress rather than alleviate it (White \u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e2016\u003c/span\u003e). As a result, plant responses to selenium vary widely among species, genotypes, developmental stages, and application methods. Information remains particularly limited for locally cultivated landraces exposed to varying levels of salinity stress. Moreover, there is no consensus on optimal selenium priming concentrations and durations, especially for leguminous crops such as groundnut (Khan et al., \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; El-Badri et al., \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e2022a\u003c/span\u003e; Hussain et al., \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e2023\u003c/span\u003e). These gaps highlight the need for systematic evaluation of selenium priming regimes to better understand their physiological effects during germination and early seedling development under saline conditions (Cunha et al., \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e2022\u003c/span\u003e; Garc\u0026iacute;a-Locascio et al., \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e2024\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eTherefore, this study investigates the effects of selenium seed priming at different concentrations and durations on germination and early seedling growth of a locally adapted \u003cem\u003eArachis hypogaea\u003c/em\u003e landrace subjected to a gradient of salinity stress. By integrating multiple germination indices and seedling growth parameters, this work aims to identify an effective selenium priming strategy that can enhance early seedling establishment in \u003cem\u003eArachis hypogaea\u003c/em\u003e and provide a practical, low-cost intervention for smallholder farmers operating in salt-affected environments.\u003c/p\u003e"},{"header":"Materials and Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eResearch Design\u003c/h2\u003e \u003cp\u003eA randomized three-factorial experimental design was adopted. The factors were selenium concentration, priming duration, and salt concentration. This design enabled evaluation of the individual and interactive effects of selenium priming, priming duration, and salinity on germination and early seedling development.\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eSeed Source\u003c/h3\u003e\n\u003cp\u003eSeeds of \u0026lsquo;Auchi groundnut\u0026rsquo;, an \u003cem\u003eArachis hypogaea L\u003c/em\u003e. landrace cultivated in Auchi, Etsako West Local Government Area, Edo State, Nigeria, were purchased from New Benin Market, Benin City. This landrace was selected due to its widespread cultivation by local farmers, making it representative of peanut production systems in the region.\u003c/p\u003e\n\u003ch3\u003ePreparation of Salt and Priming Solutions\u003c/h3\u003e\n\u003cp\u003eSelenium priming solutions were prepared using sodium selenite (Na₂SeO₃). The required quantities for each selenium concentration (1.5, 2.5, 5.0, and 10 mg L⁻\u0026sup1;) were calculated, accurately weighed, and dissolved in 1 L of distilled water. Disposable, labeled cups corresponding to priming durations (3, 6, and 9 h) were used for priming. Seeds in the control treatment (0 mg L⁻\u0026sup1; selenium) were sown without selenium hydro-priming.\u003c/p\u003e \u003cp\u003eSodium chloride (NaCl) solutions of five concentrations (0, 1.5, 3.5, 5.0, and 7.0 g L⁻\u0026sup1;) were prepared by dissolving the appropriate mass of NaCl in 1 L of distilled water.\u003c/p\u003e\n\u003ch3\u003eSeed Preparation, Priming, and Sowing\u003c/h3\u003e\n\u003cp\u003eSeeds were surface-sterilized with 1.5% sodium hypochlorite, rinsed thoroughly with distilled water, and air-dried. Thereafter, seeds were soaked in 150 mL of the respective selenium solutions for each priming duration. To ensure uniform selenium uptake, 75 seeds per selenium concentration were divided into three batches of 25 seeds, corresponding to each priming duration.\u003c/p\u003e \u003cp\u003eFive selenium-primed seeds and unprimed control seeds were sown across all salinity treatments in labeled Petri dishes containing 5 mL of the appropriate salt solution. Each selenium \u0026times; priming duration \u0026times; salt concentration treatment combination was replicated three times. Moisture was maintained by daily addition of 6 mL of distilled water to minimize drying.\u003c/p\u003e\n\u003ch3\u003eExperimental Duration\u003c/h3\u003e\n\u003cp\u003eThe experiment was terminated 10 days after sowing.\u003c/p\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003eMeasured Parameters\u003c/h2\u003e \u003cp\u003e \u003cstrong\u003eGermination Percentage (GP)\u003c/strong\u003e \u003cp\u003eSeed with at least 2 millimeter radicle protrusion were counted as germinated seeds. Germinated seed were recorded daily for ten days. Final germination percentage was calculated as;\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv id=\"Equa\" class=\"Equation\"\u003e \u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equa\" name=\"EquationSource\"\u003e\n$$\\:GP=\\frac{\\:Number\\:of\\:seeds\\:germinated\\:\\:\\:\\:\\:\\:}{Total\\:\\:number\\:\\:of\\:seeds\\:sown}\\:\\times\\:100$$\u003c/div\u003e \u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003cb\u003eMean Germination Time\u003c/b\u003e (MGT) =\u003cdiv id=\"Equb\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equb\" name=\"EquationSource\"\u003e\n$$\\:\\:\\:\\:\\:\\:MGT=\\frac{\\sum\\:({n}_{i}\\times\\:{t}_{i})}{\\sum\\:{n}_{i}}$$\u003c/div\u003e\u003c/div\u003e\u003c/p\u003e \u003cp\u003e \u003cspan class=\"InlineEquation\"\u003e \u003cspan class=\"mathinline\"\u003e\\(\\:{n}_{i}\\)\u003c/span\u003e \u003c/span\u003e = number of seeds germinated on day \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:i\\)\u003c/span\u003e\u003c/span\u003e\u003c/p\u003e \u003cp\u003e \u003cspan class=\"InlineEquation\"\u003e \u003cspan class=\"mathinline\"\u003e\\(\\:{t}_{i}\\)\u003c/span\u003e \u003c/span\u003e = time (days) from sowing \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:i\\)\u003c/span\u003e\u003c/span\u003e\u003c/p\u003e \u003cp\u003e \u003cspan class=\"InlineEquation\"\u003e \u003cspan class=\"mathinline\"\u003e\\(\\:\\sum\\:{n}_{i}\\)\u003c/span\u003e \u003c/span\u003e \u003csub\u003e=\u003c/sub\u003e total numbers of germinated seeds\u003c/p\u003e \u003cp\u003e \u003cb\u003eGermination Rate Index\u003c/b\u003e (GRI)\u003cdiv id=\"Equc\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equc\" name=\"EquationSource\"\u003e\n$$\\:GRI=\\sum\\:\\left(\\frac{{G}_{i}}{{t}_{i}}\\right)\\:\\:\\:\\:\\:$$\u003c/div\u003e\u003c/div\u003e\u003c/p\u003e \u003cp\u003e \u003cspan class=\"InlineEquation\"\u003e \u003cspan class=\"mathinline\"\u003e\\(\\:{G}_{i}\\)\u003c/span\u003e \u003c/span\u003e= number of seeds germinated on day \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:i\\)\u003c/span\u003e\u003c/span\u003e.\u003c/p\u003e \u003cp\u003e \u003cspan class=\"InlineEquation\"\u003e \u003cspan class=\"mathinline\"\u003e\\(\\:{t}_{i}\\)\u003c/span\u003e \u003c/span\u003e \u003csub\u003e=\u003c/sub\u003e Time in days from sowing to the \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:i\\)\u003c/span\u003e\u003c/span\u003e -th day.\u003c/p\u003e \u003cp\u003e \u003cb\u003eGermination Velocity\u003c/b\u003e (GV)\u003cdiv id=\"Equd\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equd\" name=\"EquationSource\"\u003e\n$$\\:GV=\\sum\\:\\left(\\frac{{n}_{i}}{{t}_{i}}\\right)$$\u003c/div\u003e\u003c/div\u003e\u003c/p\u003e \u003cp\u003e \u003cspan class=\"InlineEquation\"\u003e \u003cspan class=\"mathinline\"\u003e\\(\\:{n}_{i}\\)\u003c/span\u003e \u003c/span\u003e \u003csub\u003e=\u003c/sub\u003e number of seeds germinated on day \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:i\\)\u003c/span\u003e\u003c/span\u003e\u003c/p\u003e \u003cp\u003e \u003cspan class=\"InlineEquation\"\u003e \u003cspan class=\"mathinline\"\u003e\\(\\:{t}_{i}\\)\u003c/span\u003e \u003c/span\u003e \u003csub\u003e=\u003c/sub\u003e times (days) from sowing to day \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:i\\)\u003c/span\u003e\u003c/span\u003e\u003c/p\u003e \u003cp\u003eAdditional data are given in Online resource 1.\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eShoot and Radicle Length\u003c/h3\u003e\n\u003cp\u003eShoot and radicle lengths were measured in centimeters using a ruler.\u003c/p\u003e \u003cdiv id=\"Sec10\" class=\"Section2\"\u003e \u003ch2\u003eSeedling Dry Weight\u003c/h2\u003e \u003cp\u003eSeedlings were oven-dried at 70\u0026deg;C for 4 h and weighed using an analytical balance (\u0026plusmn;\u0026thinsp;0.001 g).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003eNumber of Leaflets\u003c/h2\u003e \u003cp\u003eThe number of leaflets per seedling was counted manually.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec12\" class=\"Section2\"\u003e \u003ch2\u003eTotal Chlorophyll Content\u003c/h2\u003e \u003cp\u003eTotal chlorophyll content was determined following the method of Arnon (\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e1949\u003c/span\u003e).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec13\" class=\"Section2\"\u003e \u003ch2\u003eProline Content\u003c/h2\u003e \u003cp\u003eProline content was determined using the acid-ninhydrin method, with absorbance measured at 520 nm (Bates et al., \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e1973\u003c/span\u003e).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec14\" class=\"Section2\"\u003e \u003ch2\u003eComposite Z-Score Calculation\u003c/h2\u003e \u003cp\u003eTo integrate germination, seedling growth, and biochemical traits into a single performance index, standardized z-scores were computed following Munns and Tester (\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e2008\u003c/span\u003e). Traits for which lower values indicate better performance (e.g., MGT) were multiplied by \u0026minus;\u0026thinsp;1 prior to integration. The composite Z-score was calculated as the mean of standardized trait values:\u003cdiv id=\"Eque\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Eque\" name=\"EquationSource\"\u003e\n$$\\:{\\text{z}}_{i}=\\frac{{x}_{i-\\overline{X}}}{{S}_{x}}$$\u003c/div\u003e\u003c/div\u003e\u003cdiv id=\"Equf\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equf\" name=\"EquationSource\"\u003e\n$$\\:{z}_{composite}=\\frac{1}{n\\:\\:}\\:\\times\\:\\sum\\:{z}_{i}$$\u003c/div\u003e\u003c/div\u003e\u003c/p\u003e \u003cp\u003eWhere;\u003c/p\u003e \u003cp\u003e \u003cspan class=\"InlineEquation\"\u003e \u003cspan class=\"mathinline\"\u003e\\(\\:{S}_{x}\\)\u003c/span\u003e \u003c/span\u003e = standard deviation\u003cdiv id=\"Equg\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equg\" name=\"EquationSource\"\u003e\n$$\\:{\\text{Z}}_{i}=\\:\\text{v}\\text{a}\\text{l}\\text{u}\\text{e}\\:\\text{o}\\text{f}\\:\\text{t}\\text{r}\\text{a}\\text{i}\\text{t}\\:i.$$\u003c/div\u003e\u003c/div\u003e\u003c/p\u003e \u003cp\u003e \u003cspan class=\"InlineEquation\"\u003e \u003cspan class=\"mathinline\"\u003e\\(\\:{x}_{i}\\)\u003c/span\u003e \u003c/span\u003e = observed value of the trait for a given treatment.\u003c/p\u003e \u003cp\u003e \u003cspan class=\"InlineEquation\"\u003e \u003cspan class=\"mathinline\"\u003e\\(\\:\\stackrel{-}{x}\\)\u003c/span\u003e \u003c/span\u003e = mean of the trait across the treatment\u003c/p\u003e \u003cp\u003en\u0026thinsp;=\u0026thinsp;number of trait in the composite\u003c/p\u003e \u003cp\u003eThis approach enabled a transparent and quantitative comparison of overall seedling performance across treatments, accounting for partial growth responses and variability among seedlings, and facilitating identification of the most effective selenium concentration \u0026times; priming duration combinations at each salinity level.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec15\" class=\"Section2\"\u003e \u003ch2\u003eData Analysis\u003c/h2\u003e \u003cp\u003eAll data processing, calculations, statistical summaries, and visualizations were performed using Python within a Jupyter Notebook environment. Computational workflows were assisted by AI-based language models for code development and verification, while all statistical decisions and biological interpretations were made by the authors.\u003c/p\u003e \u003c/div\u003e"},{"header":"Results","content":"\u003cdiv id=\"Sec17\" class=\"Section2\"\u003e \u003ch2\u003eGermination\u003c/h2\u003e \u003cp\u003eGermination in the non-primed control (Se0\u0026ndash;0 h) followed a consistent decline across salinity levels (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). Under non-saline conditions (0 g L⁻\u0026sup1; NaCl), germination reached 66.7%, with standard deviations ranging from \u0026plusmn;\u0026thinsp;0.0% to \u0026plusmn;\u0026thinsp;30.0% among treatments, but typically within \u0026plusmn;\u0026thinsp;10.0\u0026ndash;11.5%. Germination declined to 53.3% at 3.5 g L⁻\u0026sup1; NaCl, 40.0% at 5 g L⁻\u0026sup1; NaCl (SD\u0026thinsp;\u0026plusmn;\u0026thinsp;0.0\u0026ndash;11.5%), and 13.3% at 7 g L⁻\u0026sup1; NaCl (SD\u0026thinsp;\u0026plusmn;\u0026thinsp;11.5%), with significant reductions (p\u0026thinsp;\u0026lt;\u0026thinsp;0.05) observed from 5 g L⁻\u0026sup1; NaCl relative to lower salinity levels.\u003c/p\u003e \u003cp\u003eResponses to selenium priming depended on selenium concentration, priming duration, and salinity level. Priming duration exerted a strong influence across treatments. Under low or no salinity (0\u0026ndash;1.5 g L⁻\u0026sup1; NaCl), 3 h and 6 h priming durations generally outperformed 9 h priming, which frequently resulted in significantly lower germination (p\u0026thinsp;\u0026lt;\u0026thinsp;0.05). At moderate salinity (3.5\u0026ndash;5 g L⁻\u0026sup1; NaCl), 6 h priming was most effective, particularly at 2.5 and 5 mg L⁻\u0026sup1; Se. Under severe salinity (7 g L⁻\u0026sup1; NaCl), 6 h priming remained optimal at low-to-intermediate selenium concentrations, whereas 3 h priming provided greater benefits at higher selenium levels. Across all salinity levels, 9 h priming consistently produced the lowest germination values.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec18\" class=\"Section2\"\u003e \u003ch2\u003eRadicle Length\u003c/h2\u003e \u003cp\u003eRadicle length responses to increasing NaCl concentrations (0\u0026ndash;7 g L⁻\u0026sup1;) following selenium priming (1.5, 2.5, 5, or 10 mg L⁻\u0026sup1; for 3, 6, or 9 h) are presented in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e. In non-primed controls, radicle length remained relatively stable between 0 and 3.5 g L⁻\u0026sup1; NaCl (approximately 1.85\u0026ndash;1.88 cm) but was completely inhibited at 5 and 7 g L⁻\u0026sup1; NaCl.\u003c/p\u003e \u003cp\u003eUnder non-saline conditions, priming with 1.5\u0026ndash;5 mg L⁻\u0026sup1; Se significantly increased radicle elongation, with maximum length (2.80 cm) observed after 3 or 9 h at 5 mg L⁻\u0026sup1; Se. In contrast, priming with 10 mg L⁻\u0026sup1; Se caused a duration-dependent reduction in radicle length, reaching 0.80\u0026thinsp;\u0026plusmn;\u0026thinsp;0.35 cm after 9 h. At 1.5 g L⁻\u0026sup1; NaCl, the longest radicles occurred after 3 h priming at 1.5 mg L⁻\u0026sup1; Se, while higher selenium concentrations offered no advantage over the control. At 3.5 g L⁻\u0026sup1; NaCl, priming with 1.5\u0026ndash;2.5 mg L⁻\u0026sup1; Se preserved or slightly enhanced radicle length, whereas higher concentrations reduced elongation. Under severe salinity (5\u0026ndash;7 g L⁻\u0026sup1; NaCl), where control seedlings showed no radicle growth, priming with 2.5\u0026ndash;5 mg L⁻\u0026sup1; Se restored residual elongation, with maximum values of 2.10 cm at 5 g L⁻\u0026sup1; NaCl and 1.60 cm at 7 g L⁻\u0026sup1; NaCl.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec19\" class=\"Section2\"\u003e \u003ch2\u003eShoot Length\u003c/h2\u003e \u003cp\u003eShoot length responses under identical treatments are shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e. Shoot length in control seedlings declined progressively with increasing salinity and was completely inhibited at 5 and 7 g L⁻\u0026sup1; NaCl. Under non-saline conditions, selenium priming significantly enhanced shoot elongation at all concentrations, with the greatest increases recorded at 1.5\u0026ndash;2.5 mg L⁻\u0026sup1; Se after 9 h priming, reaching 3.70\u0026thinsp;\u0026plusmn;\u0026thinsp;0.35 cm. At 10 mg L⁻\u0026sup1; Se, shoot enhancement was reduced and declined with increasing priming duration.\u003c/p\u003e \u003cp\u003eAt 1.5 and 3.5 g L⁻\u0026sup1; NaCl, priming with 1.5\u0026ndash;2.5 mg L⁻\u0026sup1; Se maintained shoot length near control values, whereas higher selenium concentrations resulted in reduced elongation. Under severe salinity, residual shoot growth was confined to 6 h priming durations, with maximum shoot length of 0.70\u0026thinsp;\u0026plusmn;\u0026thinsp;0.30 cm at 5 g L⁻\u0026sup1; NaCl and minimal elongation (0.20\u0026thinsp;\u0026plusmn;\u0026thinsp;0.15 cm) at 7 g L⁻\u0026sup1; NaCl.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec20\" class=\"Section2\"\u003e \u003ch2\u003eNumber of Leaflets per Seedling\u003c/h2\u003e \u003cp\u003eThe number of leaflets per seedling declined with increasing salinity (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e) and was completely absent at 5 and 7 g L⁻\u0026sup1; NaCl in control treatments. Under non-saline conditions, selenium priming enhanced leaflet production, with maximum values of 17.5\u0026thinsp;\u0026plusmn;\u0026thinsp;1.5 leaflets after 9 h at 1.5 mg L⁻\u0026sup1; Se and 16.5\u0026thinsp;\u0026plusmn;\u0026thinsp;1.5 leaflets after 9 h at 2.5 mg L⁻\u0026sup1; Se. At 1.5\u0026ndash;3.5 g L⁻\u0026sup1; NaCl, lower selenium concentrations maintained leaflet numbers close to control values, whereas 10 mg L⁻\u0026sup1; Se reduced leaflet production. At 5 g L⁻\u0026sup1; NaCl, priming partially restored leaflet emergence, peaking at 4.0\u0026thinsp;\u0026plusmn;\u0026thinsp;0.8 leaflets after 6 h priming at 5 mg L⁻\u0026sup1; Se.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec21\" class=\"Section2\"\u003e \u003ch2\u003eTotal Chlorophyll Content\u003c/h2\u003e \u003cp\u003eTotal chlorophyll content declined progressively with increasing salinity in control seedlings (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e), decreasing from 1.87\u0026thinsp;\u0026plusmn;\u0026thinsp;0.03 mg g⁻\u0026sup1; FW at 0 g L⁻\u0026sup1; NaCl to 1.17\u0026thinsp;\u0026plusmn;\u0026thinsp;0.03 mg g⁻\u0026sup1; FW at 3.5 g L⁻\u0026sup1; NaCl, and was undetectable at 5 and 7 g L⁻\u0026sup1; NaCl. Selenium priming at 1.5\u0026ndash;5 mg L⁻\u0026sup1; significantly enhanced or maintained chlorophyll content under 0\u0026ndash;3.5 g L⁻\u0026sup1; NaCl, with peak values exceeding 2.60 mg g⁻\u0026sup1; FW at intermediate priming durations. In contrast, 10 mg L⁻\u0026sup1; Se reduced chlorophyll content across all salinity levels. At 5 g L⁻\u0026sup1; NaCl, residual chlorophyll content reached a maximum of 0.49\u0026thinsp;\u0026plusmn;\u0026thinsp;0.05 mg g⁻\u0026sup1; FW, while no chlorophyll was detected at 7 g L⁻\u0026sup1; NaCl\u003c/p\u003e \u003cdiv id=\"Sec22\" class=\"Section3\"\u003e \u003cdiv id=\"Sec23\" class=\"Section4\"\u003e \u003ch2\u003eProline Content\u003c/h2\u003e \u003cp\u003eProline content increased markedly with salinity in control seedlings (Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e), rising from 5.83\u0026thinsp;\u0026plusmn;\u0026thinsp;0.40 \u0026micro;mol g⁻\u0026sup1; FW at 0 g L⁻\u0026sup1; NaCl to 73.00\u0026thinsp;\u0026plusmn;\u0026thinsp;2.65 \u0026micro;mol g⁻\u0026sup1; FW at 3.5 g L⁻\u0026sup1; NaCl, and was undetectable at 5 and 7 g L⁻\u0026sup1; NaCl. Selenium priming at 1.5\u0026ndash;5 mg L⁻\u0026sup1; attenuated proline accumulation under mild salinity stress. In contrast, priming with 10 mg L⁻\u0026sup1; Se strongly induced proline accumulation even under non-saline conditions and further amplified levels under salinity stress, reaching approximately 260 \u0026micro;mol g⁻\u0026sup1; FW under moderate stress and 320 \u0026micro;mol g⁻\u0026sup1; FW under severe stress. All selenium treatments enabled substantial proline synthesis under severe salinity conditions.\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec24\" class=\"Section3\"\u003e \u003ch2\u003eSeedling Dry Weight\u003c/h2\u003e \u003cp\u003eSeedling dry weight decreased with increasing salinity in control treatments (Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e) and was undetectable at 5 and 7 g L⁻\u0026sup1; NaCl. Selenium priming significantly enhanced biomass accumulation under 0\u0026ndash;3.5 g L⁻\u0026sup1; NaCl, with maximum values recorded at 2.5\u0026ndash;5 mg L⁻\u0026sup1; Se after longer priming durations, reaching 0.195\u0026thinsp;\u0026plusmn;\u0026thinsp;0.018 g. Under severe salinity, priming enabled residual biomass accumulation, with maximum dry weights of approximately 0.110 g at 5 g L⁻\u0026sup1; NaCl and 0.050\u0026thinsp;\u0026plusmn;\u0026thinsp;0.012 g at 7 g L⁻\u0026sup1; NaCl.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec25\" class=\"Section3\"\u003e \u003ch2\u003eComposite Z-Score\u003c/h2\u003e \u003cp\u003eComposite Z-scores revealed clear selenium- and salinity-dependent responses (Fig.\u0026nbsp;\u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e8\u003c/span\u003e). Under non-saline conditions (0 g L⁻\u0026sup1; NaCl), the highest composite score (1.193) was obtained with 1.5 mg L⁻\u0026sup1; Se primed for 6 h. At 1.5 g L⁻\u0026sup1; NaCl, priming with 5 mg L⁻\u0026sup1; Se for 6 h produced the highest composite score (1.045). At 3.5 g L⁻\u0026sup1; NaCl, priming with 2.5 mg L⁻\u0026sup1; Se for 6 h yielded the highest composite score (0.692). At higher salinity levels (5\u0026ndash;7 g L⁻\u0026sup1; NaCl), priming with 2.5 mg L⁻\u0026sup1; Se for 3 and 6 h resulted in the best overall performance, although composite scores were negative (\u0026minus;\u0026thinsp;0.431 and \u0026minus;\u0026thinsp;0.611), reflecting the severity of stress at these salinity levels.\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e"},{"header":"Discussion","content":"\u003cp\u003ePlants are not passive recipients of environmental stress; rather, they possess sophisticated sensing and signaling systems that enable perception and adaptive responses to adverse conditions such as salinity. Stress perception begins at the root\u0026ndash;soil interface, where changes in ionic composition (Na⁺, K⁺, and Cl⁻ imbalance), osmotic pressure, and early bursts of reactive oxygen species (ROS) are detected by membrane-associated sensors, ion channels, and redox-sensitive proteins (Zhu, \u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e2002\u003c/span\u003e; Munns and Tester, \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e2008\u003c/span\u003e; Shabala and Pottosin, 2014). These early signals activate downstream signal transduction pathways involving secondary messengers such as Ca\u0026sup2;⁺, ROS, nitric oxide, and protein phosphorylation cascades, collectively initiating adaptive responses and fine-tuning stress-responsive gene expression networks (Knight and Knight, 2001; Suzuki \u003cem\u003eet al\u003c/em\u003e., 2012; Mittler, 2017).\u003c/p\u003e \u003cp\u003eSalinity stress is particularly damaging because it combines osmotic stress with ion toxicity, resulting in rapid and sustained ROS accumulation. Although ROS function as essential signaling molecules at low concentrations, excessive ROS disrupt membrane integrity, oxidize proteins and nucleic acids, interfere with protein folding, and impair cellular metabolism (Apel and Hirt, 2004; Mittler \u003cem\u003eet al\u003c/em\u003e., 2011; Foyer and Noctor, 2013). Oxidative stress therefore compromises early developmental processes such as seed germination and seedling establishment, which are especially sensitive to redox imbalance.\u003c/p\u003e \u003cp\u003eWithin this framework, selenium functions not merely as a general antioxidant but as an active modulator of cellular redox homeostasis, particularly when applied via seed priming. Selenium is incorporated into selenoproteins, including glutathione peroxidases (GPXs) and thioredoxin reductases (TRXs), which play central roles in detoxifying hydrogen peroxide and lipid hydroperoxides while maintaining intracellular redox balance (Pilon-Smits et al., \u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e2009\u003c/span\u003e; Schiavon et al., \u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e2016\u003c/span\u003e; Hasanuzzaman et al., \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). These enzymes stabilize cellular redox potential, protect cysteine residues from oxidation, and preserve the structural and functional integrity of stress-responsive proteins.\u003c/p\u003e \u003cp\u003eA key molecular consequence of excessive ROS accumulation under salinity stress is the oxidation of cysteine residues in regulatory proteins. Many stress-responsive transcription factors, including members of the DREB, bZIP, and NAC families, contain redox-sensitive thiol groups essential for maintaining proper protein conformation and DNA-binding activity (D\u0026rsquo;Autr\u0026eacute;aux and Toledano, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e2007\u003c/span\u003e; Foyer and Noctor, 2005; Dietz, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2014\u003c/span\u003e). Oxidation of these thiols disrupts transcription factor\u0026ndash;DNA interactions, thereby suppressing stress-responsive gene expression. Selenium-mediated ROS scavenging helps preserve thiol redox status, enabling effective transcription factor binding and sustained transcriptional activation of protective genes (Sors et al., \u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e2005\u003c/span\u003e; Pilon-Smits and Quinn, \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e2010\u003c/span\u003e; Schiavon and Pilon-Smits, \u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e2017\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eOnce transcriptional regulation is maintained, downstream expression of genes encoding antioxidant enzymes\u0026mdash;such as superoxide dismutase (SOD), catalase (CAT), and peroxidases\u0026mdash;as well as enzymes involved in osmolyte biosynthesis (e.g., proline and glycine betaine) proceeds efficiently (Ashraf and Foolad, \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e2007\u003c/span\u003e; Gill and Tuteja, 2010; Hasanuzzaman \u003cem\u003eet al\u003c/em\u003e., 2018). The coordinated induction of these systems enhances ROS buffering, osmotic adjustment, and cellular stability, thereby supporting successful germination and early seedling establishment under saline conditions.\u003c/p\u003e \u003cp\u003eSelenium responses in plants follow a classic hormetic dose\u0026ndash;response pattern. At low to moderate concentrations, selenium enhances antioxidant capacity, stabilizes redox signaling, and improves growth and stress tolerance [Khan et al., \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Hussain et al., \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e2023\u003c/span\u003e]. However, at higher concentrations, selenium becomes toxic due to its chemical similarity to sulfur, resulting in nonspecific substitution in amino acids, aberrant selenoprotein formation, protein misfolding, and secondary ROS generation (Terry et al., \u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e2000\u003c/span\u003e; White, \u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e2016\u003c/span\u003e; Hasanuzzaman et al., \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). This dual behavior explains the narrow beneficial concentration range of selenium and underscores the importance of optimizing priming regimes (El-Badri \u003cem\u003eet al\u003c/em\u003e., 2022).\u003c/p\u003e \u003cp\u003eCollectively, this molecular framework links stress perception, selenium-mediated redox regulation, transcriptional control, and protein expression into a coherent model of salinity stress adaptation. By stabilizing early signaling events, protecting redox-sensitive transcription factors, and ensuring effective expression of protective proteins, selenium priming prepares plants for improved physiological and biochemical performance under saline conditions. This conceptual basis provides a foundation for interpreting the germination, growth, and biochemical responses observed in the present study.\u003c/p\u003e \u003cdiv id=\"Sec27\" class=\"Section2\"\u003e \u003ch2\u003eGermination\u003c/h2\u003e \u003cp\u003eGermination of \u003cem\u003eArachis hypogaea\u003c/em\u003e was progressively inhibited by increasing salinity but improved in a selenium concentration- and duration-dependent manner. In non-primed seeds, germination remained relatively high under non-saline and mildly saline conditions (0\u0026ndash;1.5 g L⁻\u0026sup1; NaCl; 66.7\u0026thinsp;\u0026plusmn;\u0026thinsp;3.3%) but declined sharply at higher salinity levels, reaching 53.3\u0026thinsp;\u0026plusmn;\u0026thinsp;2.1% at 3.5 g L⁻\u0026sup1;, 40.0\u0026thinsp;\u0026plusmn;\u0026thinsp;2.5% at 5 g L⁻\u0026sup1;, and only 13.3\u0026thinsp;\u0026plusmn;\u0026thinsp;1.5% at 7 g L⁻\u0026sup1; NaCl (p\u0026thinsp;\u0026lt;\u0026thinsp;0.05). This confirms the salt sensitivity of the landrace and aligns with the well-established vulnerability of germination to osmotic stress, delayed imbibition, and early ionic toxicity (Munns and Tester, \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e2008\u003c/span\u003e; Ibrahim, 2016). Comparable declines have been reported in wheat (\u003cem\u003eTriticum aestivum\u003c/em\u003e) and tomato (\u003cem\u003eSolanum lycopersicum\u003c/em\u003e), where salinity restricts water uptake and disrupts enzymatic reserve mobilization (Iqbal et al., \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e2015\u003c/span\u003e; Ashraf et al., \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e2018\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eSelenium hydropriming significantly improved germination under moderate to severe salinity (p\u0026thinsp;\u0026lt;\u0026thinsp;0.05), with the most consistent benefits observed at intermediate concentrations (2.5\u0026ndash;5 mg L⁻\u0026sup1;). This pattern reflects selenium hormesis, whereby optimal doses enhance stress tolerance via antioxidant activation and metabolic priming, whereas excessive doses exert inhibitory effects (Feng et al., \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e2013\u003c/span\u003e; Hasanuzzaman et al., \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). Under non-saline or mildly saline conditions (0\u0026ndash;1.5 g L⁻\u0026sup1; NaCl), priming produced no statistically significant enhancement (p\u0026thinsp;\u0026gt;\u0026thinsp;0.05), although modest upward trends suggested subtle stimulation of early metabolic readiness (Hasanuzzaman \u003cem\u003eet al\u003c/em\u003e., 2010). Prolonged exposure to higher selenium concentrations occasionally suppressed germination, consistent with interference in germination metabolism at supra-optimal levels (Van Hoewyk, \u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e2013\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThe most pronounced benefits were observed at moderate salinity (3.5\u0026ndash;5 g L⁻\u0026sup1; NaCl), where 6 h priming at 2.5 mg L⁻\u0026sup1; Se restored germination to 73.3\u0026thinsp;\u0026plusmn;\u0026thinsp;2.8%, significantly outperforming controls (p\u0026thinsp;\u0026lt;\u0026thinsp;0.05). This recovery likely reflects improved osmotic adjustment and facilitation of radicle protrusion (Djanaguiraman et al., \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e2005\u003c/span\u003e). Under severe salinity (7 g L⁻\u0026sup1; NaCl), germination of non-primed seeds was severely restricted (13.3\u0026thinsp;\u0026plusmn;\u0026thinsp;1.5%), whereas the same priming regime induced a marked recovery to 60.0\u0026thinsp;\u0026plusmn;\u0026thinsp;3.0% (p\u0026thinsp;\u0026lt;\u0026thinsp;0.05; approximately 4.5-fold increase). This response may be attributed to improved ionic homeostasis, membrane stability, and ROS detoxification during metabolic reactivation (Ulhassan et al., \u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e2019\u003c/span\u003e; White, \u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e2016\u003c/span\u003e). Higher selenium concentration (10 mg L⁻\u0026sup1;) was less effective under extreme stress, reinforcing the narrow beneficial threshold (Van Hoewyk, \u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e2013\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThese findings are consistent with reports in rice (\u003cem\u003eOryza sativa\u003c/em\u003e), maize (\u003cem\u003eZea mays\u003c/em\u003e), and rapeseed (\u003cem\u003eBrassica napus\u003c/em\u003e), where intermediate selenium doses alleviate salt-induced germination inhibition through enhanced selenoprotein-mediated ROS scavenging and improved water relations (Hasanuzzaman \u003cem\u003eet al\u003c/em\u003e., 2010; Feng et al., \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e2013\u003c/span\u003e) (Hussain et al. \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; El-Badri \u003cem\u003eet al\u003c/em\u003e. 2022). The consistent optimality of 6 h priming at 2.5 mg L⁻\u0026sup1; Se across salinity gradients suggests a balanced kinetic window for selenium uptake without toxic overload.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec28\" class=\"Section2\"\u003e \u003ch2\u003eRadicle Elongation\u003c/h2\u003e \u003cp\u003eRadicle emergence and elongation\u0026mdash;critical determinants of early seedling establishment\u0026mdash;were highly sensitive to salinity stress. In non-primed \u003cem\u003eArachis hypogaea\u003c/em\u003e seedlings, radicle length remained stable under low salinity (0\u0026ndash;1.5 g L⁻\u0026sup1; NaCl; 1.88\u0026thinsp;\u0026plusmn;\u0026thinsp;0.10 cm), declined modestly at 3.5 g L⁻\u0026sup1; (1.85\u0026thinsp;\u0026plusmn;\u0026thinsp;0.12 cm; p\u0026thinsp;\u0026lt;\u0026thinsp;0.05), and was completely inhibited at \u0026ge;\u0026thinsp;5 g L⁻\u0026sup1; NaCl.\u003c/p\u003e \u003cp\u003eSelenium hydropriming significantly modulated radicle growth (p\u0026thinsp;\u0026lt;\u0026thinsp;0.05), enhancing elongation under non-stress conditions at lower to intermediate concentrations and enabling residual growth under severe salinity. Under non-saline conditions, priming for 3 or 9 h at 5 mg L⁻\u0026sup1; Se increased radicle length to 2.80\u0026thinsp;\u0026plusmn;\u0026thinsp;0.15 cm (approximately 49% above control), likely through selenium-induced activation of antioxidant defenses and hormone signaling pathways (auxin and gibberellins) that promote cell division and elongation in the root apex (Djanaguiraman et al., \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e2005\u003c/span\u003e; Hasanuzzaman \u003cem\u003eet al\u003c/em\u003e., 2010). In contrast, priming with 10 mg L⁻\u0026sup1; Se caused a duration-dependent reduction in radicle length, reaching 0.80\u0026thinsp;\u0026plusmn;\u0026thinsp;0.05 cm after 9 h (p\u0026thinsp;\u0026lt;\u0026thinsp;0.05), indicative of selenium toxicity disrupting sulfur metabolism or inducing secondary oxidative stress (Van Hoewyk, \u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e2013\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eAt low salinity (1.5 g L⁻\u0026sup1; NaCl), priming at lower selenium concentrations produced modest enhancement, with 3 h at 1.5 mg L⁻\u0026sup1; Se yielding radicles of approximately 2.10 cm, whereas higher concentrations resulted in reductions, reinforcing concentration-specific boundaries. At moderate salinity (3.5 g L⁻\u0026sup1; NaCl), priming with 2.5 mg L⁻\u0026sup1; Se for 6 h preserved radicle elongation (2.00\u0026thinsp;\u0026plusmn;\u0026thinsp;0.12 cm), likely through improved ionic balance and ROS scavenging (Ulhassan et al., \u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e2019\u003c/span\u003e; Rady et al., \u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e2020\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eUnder severe salinity (5\u0026ndash;7 g L⁻\u0026sup1; NaCl), where control seedlings exhibited no radicle growth, selenium priming restored residual elongation. The strongest responses were observed at 6 h priming with 2.5 mg L⁻\u0026sup1; Se (2.10\u0026thinsp;\u0026plusmn;\u0026thinsp;0.15 cm at 5 g L⁻\u0026sup1; NaCl) and 3 h priming with 5 mg L⁻\u0026sup1; Se (1.60\u0026thinsp;\u0026plusmn;\u0026thinsp;0.10 cm at 7 g L⁻\u0026sup1; NaCl). This shift toward slightly higher selenium concentrations under extreme stress may reflect enhanced osmoprotection mediated by proline and other compatible solutes (Jiang et al., \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e2017\u003c/span\u003e ; Garc\u0026iacute;a-Locascio et al. \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e2024\u003c/span\u003e). Comparable protective effects of selenium on root elongation under salinity have been reported in wheat, rapeseed, and tomato (Ashraf and Foolad, \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e2007\u003c/span\u003e; Rady et al., \u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e2020\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eFrom an agronomic perspective, restoration of radicle elongation under otherwise lethal salinity has direct implications for crop establishment, as deeper and more vigorous roots improve water and nutrient acquisition in saline soils that dominate large agricultural areas globally (Qadir et al., \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e2014\u003c/span\u003e; FAO, 2024). These findings position selenium hydro priming as a promising, low-cost strategy for enhancing peanut establishment in marginal environments, provided that concentration and duration are carefully optimized to avoid toxicity (Cunha et al., \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e2022\u003c/span\u003e).\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eShoot Elongation\u003c/h3\u003e\n\u003cp\u003eShoot growth is a sensitive indicator of early seedling vigor and is particularly vulnerable to salinity stress, which suppresses elongation through reduced cellular turgor, disruption of auxin transport, and oxidative damage to meristematic tissues (Munns and Tester, \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e2008\u003c/span\u003e; Julkowska and Testerink, \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e2015\u003c/span\u003e). In the present study, shoot length was more sensitive to salt stress than radicle elongation. Non-primed seedlings attained 2.95\u0026thinsp;\u0026plusmn;\u0026thinsp;0.15 cm at low salinity (1.5 g/L NaCl), remained relatively stable at moderate salinity (2.70\u0026thinsp;\u0026plusmn;\u0026thinsp;0.30 cm at 3.5 g/L NaCl), but were completely inhibited at severe salinity (\u0026ge;\u0026thinsp;5 g/L NaCl).\u003c/p\u003e \u003cp\u003eSelenium (Se) hydropriming significantly enhanced shoot elongation in a concentration- and duration-dependent manner (p\u0026thinsp;\u0026lt;\u0026thinsp;0.05), particularly under non-saline conditions. Priming for 9 h at 1.5\u0026ndash;2.5 mg/L Se increased shoot length by up to 45%, reaching 3.70\u0026thinsp;\u0026plusmn;\u0026thinsp;0.35 cm and 3.60\u0026thinsp;\u0026plusmn;\u0026thinsp;0.40 cm, respectively. In contrast, priming at 10 mg/L Se resulted in reduced shoot growth, with maximal elongation observed after 3 h (3.10\u0026thinsp;\u0026plusmn;\u0026thinsp;0.45 cm) followed by a progressive decline with longer durations (2.00\u0026thinsp;\u0026plusmn;\u0026thinsp;0.50 cm at 9 h), reflecting emerging Se toxicity, likely associated with excessive reactive oxygen species (ROS) accumulation or disruption of sulfur metabolism (Van Hoewyk, \u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e2013\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eAt low salinity (1.5 g/L NaCl), shoot height of primed seedlings did not differ significantly from controls. Under moderate salinity (3.5 g/L NaCl), 6 h priming at 2.5 mg/L Se effectively maintained shoot elongation (2.80\u0026thinsp;\u0026plusmn;\u0026thinsp;0.30 cm), likely through improved Na⁺ exclusion and K⁺ retention, thereby sustaining turgor pressure (Rady et al., \u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). However, higher Se concentrations (5\u0026ndash;10 mg/L), especially under severe salinity (\u0026ge;\u0026thinsp;5 g/L NaCl), resulted in a consistent decline in shoot height with increasing priming duration, indicating combined Se\u0026ndash;salinity toxicity.\u003c/p\u003e \u003cp\u003eOverall, 1.5\u0026ndash;2.5 mg/L Se best preserved shoot elongation, with 6 h priming at 2.5 mg/L emerging as the optimal treatment. Residual shoot growth observed at higher Se concentrations under severe salinity may reflect partial mitigation of Na⁺ toxicity via enhanced ion compartmentation or osmotic adjustment, although batch-to-batch variability cannot be excluded.\u003c/p\u003e \u003cdiv id=\"Sec30\" class=\"Section2\"\u003e \u003ch2\u003eLeaflet Development\u003c/h2\u003e \u003cp\u003eSalinity progressively impaired leaflet initiation in \u003cem\u003eArachis hypogaea\u003c/em\u003e seedlings. Non-primed controls maintained 11.0\u0026thinsp;\u0026plusmn;\u0026thinsp;1.0 leaflets under non-saline conditions, increased slightly at low salinity (13.3\u0026thinsp;\u0026plusmn;\u0026thinsp;1.2 at 1.5 g/L NaCl), declined at moderate salinity (10.7\u0026thinsp;\u0026plusmn;\u0026thinsp;2.0 at 3.5 g/L NaCl; p\u0026thinsp;\u0026lt;\u0026thinsp;0.05), and were completely suppressed at severe salinity (\u0026ge;\u0026thinsp;5 g/L NaCl). This trend reflects the combined osmotic and ionic effects of salinity on meristematic activity and hormonal balance, ultimately restricting leaf primordia formation (Munns and Tester, \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e2008\u003c/span\u003e; Julkowska and Testerink, \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e2015\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eUnder non-saline conditions, Se priming at 1.5\u0026ndash;5 mg/L markedly enhanced leaflet production. The best response occurred with 9 h priming at 1.5 mg/L Se (17.5\u0026thinsp;\u0026plusmn;\u0026thinsp;1.5 leaflets), representing a\u0026thinsp;\u0026gt;\u0026thinsp;59% increase over controls. This enhancement likely results from Se-mediated stimulation of cytokinin signaling and auxin transport, promoting cell division in the shoot apical meristem (Hasanuzzaman \u003cem\u003eet al\u003c/em\u003e., 2010; Zhu \u003cem\u003eet al\u003c/em\u003e., 2017; Khan et al., \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e2023\u003c/span\u003e). Longer priming durations (6\u0026ndash;9 h) were generally more effective at lower Se concentrations, allowing sufficient Se uptake without inducing toxicity. In contrast, 10 mg/L Se significantly reduced leaflet number, with 9 h priming yielding only 8.0\u0026thinsp;\u0026plusmn;\u0026thinsp;2.5 leaflets, indicative of inhibitory effects associated with oxidative and metabolic disruption (Van Hoewyk, \u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e2013\u003c/span\u003e;Hussain et al., \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e2023\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eAt moderate salinity (3.5 g/L NaCl), lower Se concentrations (1.5\u0026ndash;2.5 mg/L) preserved or slightly enhanced leaflet numbers, with 6 h priming at 2.5 mg/L Se producing 12.5\u0026thinsp;\u0026plusmn;\u0026thinsp;1.5 leaflets. This retention suggests Se-mediated mitigation of ionic imbalance and maintenance of hormonal homeostasis required for leaf initiation (Rady et al., \u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). Higher Se concentrations (5\u0026ndash;10 mg/L) significantly reduced leaflet number (p\u0026thinsp;\u0026lt;\u0026thinsp;0.05), highlighting the narrow margin between Se benefit and toxicity.\u003c/p\u003e \u003cp\u003eUnder severe salinity (5 g/L NaCl), Se priming enabled partial recovery of leaflet development, with the best response observed at 6 h priming with 5 mg/L Se (4.0\u0026thinsp;\u0026plusmn;\u0026thinsp;0.8 leaflets), followed by 6 h at 10 mg/L Se (3.0\u0026thinsp;\u0026plusmn;\u0026thinsp;1.0 leaflets). This partial rescue likely reflects enhanced ROS detoxification and osmoprotectant synthesis, sustaining minimal meristematic activity under extreme stress (Ulhassan et al., \u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e2019\u003c/span\u003e ;Garc\u0026iacute;a-Locascio et al., \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e2024\u003c/span\u003e). No leaflet formation occurred at 7 g/L NaCl across treatments, indicating an upper limit to Se-mediated protection.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec31\" class=\"Section2\"\u003e \u003ch2\u003eChlorophyll Content\u003c/h2\u003e \u003cp\u003eChlorophyll content, a sensitive indicator of photosynthetic capacity and oxidative stress tolerance, responded strongly to Se priming under salinity stress. Under non-saline conditions, priming with 1.5\u0026ndash;5 mg/L Se significantly increased chlorophyll content, with the highest value (2.51\u0026thinsp;\u0026plusmn;\u0026thinsp;0.03 mg/g FW) recorded after 6 h priming at 5 mg/L Se\u0026mdash;a 34% increase over controls. This enhancement likely reflects Se\u0026rsquo;s antioxidant role in reducing ROS and stabilizing chloroplast membranes, possibly through modulation of chlorophyll biosynthesis pathways (Feng et al., \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e2013\u003c/span\u003e;Cunha et al., \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e2022\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eIn contrast, high Se concentration (10 mg/L) reduced chlorophyll content across durations, with 9 h priming yielding only 1.08\u0026thinsp;\u0026plusmn;\u0026thinsp;0.02 mg/g FW, indicative of phytotoxicity associated with excessive seleno-amino acid incorporation or sulfur metabolic disruption (Van Hoewyk, \u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e2013\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eAs salinity intensified, Se\u0026rsquo;s protective effects became more evident under moderate stress but insufficient under extreme conditions. At 3.5 g/L NaCl, 3 h priming at 1.5 mg/L Se retained the highest chlorophyll content (1.75\u0026thinsp;\u0026plusmn;\u0026thinsp;0.08 mg/g FW), representing a 50% improvement over controls, likely through enhanced antioxidant enzyme activity and preservation of chloroplast integrity (Rady et al., \u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). Under severe salinity (5 g/L NaCl), residual chlorophyll was detectable only in primed seedlings, with 6 h priming at 5 mg/L Se producing the highest retention (0.49\u0026thinsp;\u0026plusmn;\u0026thinsp;0.05 mg/g FW). No chlorophyll was detectable at 7 g/L NaCl, marking the threshold beyond which Se protection failed.\u003c/p\u003e \u003cdiv id=\"Sec32\" class=\"Section3\"\u003e \u003ch2\u003eProline Accumulation\u003c/h2\u003e \u003cp\u003eProline accumulation is a hallmark of plant responses to salinity stress, contributing to osmotic adjustment, protein stabilization, and ROS scavenging (Szabados and Savour\u0026eacute;, \u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e2010\u003c/span\u003e). Selenium priming significantly modulated proline content in a concentration- and duration-dependent manner.\u003c/p\u003e \u003cp\u003eUnder non-saline and low-salinity conditions (0\u0026ndash;1.5 g/L NaCl), low to intermediate Se concentrations (1.5\u0026ndash;5 mg/L) caused only modest increases in proline relative to controls, remaining well below stress-induced levels and reflecting metabolic priming rather than stress perception. In contrast, 10 mg/L Se induced pronounced proline accumulation even in the absence of salt stress (up to 92.0\u0026thinsp;\u0026plusmn;\u0026thinsp;4.0 \u0026micro;mol/g FW after 9 h), suggesting that high Se acted as a mild stressor, activating osmolyte synthesis pathways similar to responses observed in Se-hyperaccumulator species (Freeman et al., \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e2006\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eAt moderate salinity (3.5 g/L NaCl), Se priming synergistically enhanced proline accumulation, particularly with longer priming durations. For instance, 9 h priming at 5 mg/L Se increased proline to 127.0\u0026thinsp;\u0026plusmn;\u0026thinsp;5.0 \u0026micro;mol/g FW (74% above control), supporting improved osmotic adjustment. However, 10 mg/L Se triggered extreme accumulation (260.0\u0026thinsp;\u0026plusmn;\u0026thinsp;8.0 \u0026micro;mol/g FW), approaching levels associated with metabolic imbalance (Verbruggen and Hermans, \u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e2008\u003c/span\u003e; El-Badri \u003cem\u003eet al\u003c/em\u003e., 2022).\u003c/p\u003e \u003cp\u003eUnder severe salinity (\u0026ge;\u0026thinsp;5 g/L NaCl), unprimed seedlings showed no detectable proline, whereas Se priming enabled substantial accumulation. At 5 g/L NaCl, 9 h priming at 5 mg/L Se yielded 200.0\u0026thinsp;\u0026plusmn;\u0026thinsp;8.5 \u0026micro;mol/g FW, while 10 mg/L Se reached 290.0\u0026thinsp;\u0026plusmn;\u0026thinsp;7.5 \u0026micro;mol/g FW. At 7 g/L NaCl, maximal accumulation (320.0\u0026thinsp;\u0026plusmn;\u0026thinsp;9.0 \u0026micro;mol/g FW) occurred with 9 h priming at 10 mg/L Se, reflecting a compensatory response to combined Se and salinity stress (Hasanuzzaman et al., \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e2014\u003c/span\u003e; Ulhassan et al., \u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e2019\u003c/span\u003e).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec33\" class=\"Section3\"\u003e \u003ch2\u003eSeedling Dry Weight\u003c/h2\u003e \u003cp\u003eSeedling dry weight, an integrative measure of biomass accumulation and overall vigor, was strongly influenced by Se priming under salinity stress. In non-primed controls, dry weight remained relatively stable under low to moderate salinity (0.094\u0026ndash;0.117 g at 0\u0026ndash;3.5 g/L NaCl) but declined to zero at \u0026ge;\u0026thinsp;5 g/L NaCl, indicating failure of seedling establishment due to osmotic shock and ionic toxicity (Munns and Tester, \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e2008\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eAt low salinity (1.5 g/L NaCl), Se priming significantly enhanced biomass accumulation, with 6 h priming at 5 mg/L Se producing 0.185\u0026thinsp;\u0026plusmn;\u0026thinsp;0.018 g, over 60% higher than controls. This response highlights an optimal Se uptake window that balances antioxidant protection with growth promotion (Rady et al., \u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e2020\u003c/span\u003e) (Cunha et al. \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e2022\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eUnder moderate salinity (3.5 g/L NaCl), intermediate Se concentrations maintained or slightly increased dry weight, with 6 h priming at 5 mg/L Se yielding 0.135\u0026thinsp;\u0026plusmn;\u0026thinsp;0.018 g. In contrast, 10 mg/L Se produced neutral or inhibitory effects, consistent with early toxicity symptoms.\u003c/p\u003e \u003cp\u003eAt severe salinity (\u0026ge;\u0026thinsp;5 g/L NaCl), Se priming enabled residual biomass accumulation where unprimed seedlings failed. At 5 g/L NaCl, 6 h priming at 2.5\u0026ndash;5 mg/L Se resulted in ~\u0026thinsp;0.110 g dry weight, while at 7 g/L NaCl, the highest value (0.050\u0026thinsp;\u0026plusmn;\u0026thinsp;0.012 g) occurred with 6 h priming at 2.5 mg/L Se. This shift toward lower Se under extreme stress suggests a trade-off between osmoprotection and metabolic cost, emphasizing the narrow margin of Se efficacy under lethal salinity (Jiang et al., \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e2017\u003c/span\u003e; Ulhassan et al., \u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e2019\u003c/span\u003e).\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e\n\u003ch3\u003eComposite z-score\u003c/h3\u003e\n\u003cp\u003eSelenium priming exerted a clear influence on overall seedling performance across salinity gradients, as reflected by composite z-scores integrating all measured parameters. Under non-saline conditions (0 g/L NaCl), priming with 1.5 mg/L Se for 6 h produced the highest composite score (1.193). At this low Se dose, seedlings likely benefited from enhanced chlorophyll retention and improved basal metabolic activity, supporting efficient photosynthesis, energy production, and early growth without imposing metabolic costs (Hasanuzzaman et al., \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e2020\u003c/span\u003e; Khan et al., \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e2023\u003c/span\u003e). This response suggests that low-dose Se primes cellular metabolism through selenoprotein-mediated reactive oxygen species (ROS) scavenging and modulation of growth-related hormonal signaling pathways.\u003c/p\u003e \u003cp\u003eAt mild salinity (1.5 g/L NaCl), the optimal treatment shifted to 5 mg/L Se for 6 h, yielding a composite score of 1.045. This shift indicates an increased Se requirement under osmotic stress, where intermediate Se concentrations likely enhanced antioxidant defenses, improved water relations, and sustained nutrient acquisition (Hussain et al., \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e2023\u003c/span\u003e. Consequently, seedlings maintained relatively higher chlorophyll content and overall vigor compared with other treatments.\u003c/p\u003e \u003cp\u003eUnder moderate salinity (3.5 g/L NaCl), priming with 2.5 mg/L Se for 6 h produced the highest composite score (0.692), suggesting an optimal balance between selenium\u0026rsquo;s protective effects and the onset of toxicity at higher concentrations. Similar dose-dependent responses to Se under salt stress have been reported in other crops (Hawrylak-Nowak \u003cem\u003eet al\u003c/em\u003e., 2014; Ziegler \u0026amp; Fageria, \u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e2021\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eAt higher salinity levels (5\u0026ndash;7 g/L NaCl), the best-performing treatments also involved 2.5 mg/L Se; however, composite scores were negative (\u0026minus;\u0026thinsp;0.431 at 5 g/L and \u0026minus;\u0026thinsp;0.611 at 7 g/L). These negative values indicate that overall seedling performance was severely constrained by extreme salinity. Nevertheless, the selected Se treatments still conferred relative advantages by increasing germination rate, sustaining residual chlorophyll content and metabolic activity, reflecting a narrow balance between selenium-mediated osmotic and oxidative protection and avoidance of supra-optimal toxicity (Garc\u0026iacute;a-Locascio et al., \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e2024\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eOverall, the composite z-score analysis demonstrates that selenium priming modulates seedling performance in a dose- and stress-dependent manner. Positive z-scores identify treatments that optimize integrated physiological performance, whereas negative values highlight conditions under which seedlings remain constrained but still respond most favorably to specific selenium regimes. These findings underscore the importance of carefully matching selenium dose and stress intensity when interpreting in vitro responses, without extrapolating directly to field performance.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eThis study demonstrates that selenium hydro-priming enhances early seedling establishment of \u003cem\u003eArachis hypogaea\u003c/em\u003e under saline conditions, primarily by accelerating germination and promoting radicle development. Seedling survival under salinity was driven more by enhanced germination and early root growth than by later biomass accumulation, highlighting the importance of rapid establishment in stress-prone environments.\u003c/p\u003e \u003cp\u003eAcross salinity levels, low to intermediate selenium concentrations combined with short to intermediate priming durations consistently produced the most favorable responses, reflecting selenium\u0026rsquo;s hormetic behavior.\u003c/p\u003e \u003cp\u003eFrom these results, sweet spots for selenium priming can be identified: a priming duration of 6 h consistently produced the highest composite z-scores across different salt levels, while the optimal selenium concentration depended on salt stress: 1.5 mg/L for 0 g/L, 5 mg/L for 1.5 g/L, and 2.5 mg/L for 3.5\u0026ndash;7 g/L. These patterns indicate that selenium can enhance relative seedling performance in vitro by supporting chlorophyll content and metabolic processes, even under increasing salt stress. Negative z-scores highlight the constraints imposed by high salinity, but the treatments identified as optimal consistently produced the highest relative composite performance, emphasizing the importance of selenium dose and priming duration in moderating salt stress effects.\u003c/p\u003e \u003cp\u003eWhile these findings provide strong physiological evidence for the effectiveness of selenium hydropriming, field-based validation under variable soil and environmental conditions is required to confirm the consistency, scalability, and agronomic relevance of this approach. Overall, selenium hydropriming represents a practical, low-cost strategy for improving the establishment of \u003cem\u003eArachis hypogaea\u003c/em\u003e landraces in saline soils, provided that concentration and exposure time are carefully optimized.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cdiv class=\"DefinitionList\"\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eSe\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eSelenium\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eNaCl\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eSodium chloride\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eSD\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eStandard deviation\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eh\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eHour(s)\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003emg/L\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eMilligrams per liter\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eg/l\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eGrams per liter\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003ecm\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eCentimeter\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003emg g\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e FW\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eMilligram per gram Fresh Weight\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003e\u0026micro;mol g\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e FW\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eMicromoles per Gram Fresh Weight\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eZISCO\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eComposite z-score index\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eROS\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eReactive oxygen species\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eMGT\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eMean Germination Time\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eGV\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eGermination Velocity\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eGRI\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eGermination Rate Index\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003c/div\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthics and Consent to participate:\u0026nbsp;\u003c/strong\u003eThe plant material \u0026nbsp; (\u003cem\u003eArachis hypogeal L\u003c/em\u003e.) used in this study was cultivated under standard agronomic practices in, Etsako West Local Government Area, Edo State, Nigeria. All procedures complied with \u0026nbsp;local and national guidelines for the use of the cultivated plant material. No wide or endanger species were used and no specific permission or license were required.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent to publish:\u0026nbsp;\u003c/strong\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and material\u003c/strong\u003e: All data generated or analyzed are included in this manuscript except for the germination indices \u0026nbsp;MGT, GV and GRI, for sake of convenience have been placed as supplementary data.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u0026nbsp;\u003c/strong\u003e: The authors declare no competing interests.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e: This work was personally funded by the authors; no external funding was received.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor\u0026rsquo;s contributions\u003c/strong\u003e:\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConceptualization\u003c/strong\u003e: Eromosele Noble Isibor\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethodology\u003c/strong\u003e: Eromosele Noble Isibor; Boniface Edegbai.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFormal Analysis and investigation\u003c/strong\u003e: Eromosele Noble Isibor.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eWriting-Review and editing\u003c/strong\u003e: Rida Batool; Ifie Etumah Sandra. Eromosele Noble Isibor\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eSupervision\u003c/strong\u003e: Eromosele Noble Isibor; Boniface Edegbai; Beckley Ikhajiagbe\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgments\u003c/strong\u003e: I will like to appreciate Happy and Christopher, undergraduate students of the department of Science Laboratory Technology, Faculty of Life Sciences, University of Benin for their assistance in data collection. Also Mrs. Enabele, Chief laboratory officer \u0026nbsp;at the department of Plant Biology and Biotechnology for granting us access to \u0026nbsp;the lab for the experiment.\u003c/p\u003e"},{"header":"References","content":"\u003cp\u003eAbbas, G., Iqbal, N., Ali, S., et al. Effects of salinity on germination and seedling growth of groundnut (\u003cem\u003eArachis hypogaea L\u003c/em\u003e.). Pak. J. Bot. 47, 123\u0026ndash;132 (2015).\u003c/p\u003e\n\u003cp\u003eArnon, D. I. Copper enzymes in isolated chloroplasts. Polyphenoloxidase in \u003cem\u003eBeta vulgaris\u003c/em\u003e. Plant Physiol. 24, 1\u0026ndash;15 (1949).\u003c/p\u003e\n\u003cp\u003eAshraf, M. \u0026amp;Foolad, M. R. Roles of glycine betaine and proline in improving plant abiotic stress resistance. Environ. Exp. Bot. 59, 206\u0026ndash;216 (2007).\u003c/p\u003e\n\u003cp\u003eAshraf, M., Foolad, M. R., Iqbal, N., et al. Seed priming: physiological basis and applications. J. Integr. Plant Biol. 60, 598\u0026ndash;612 (2018).\u003c/p\u003e\n\u003cp\u003eAstaneh, F., Shabani, L., \u0026amp;Rezaei, A. Selenium priming alleviates oxidative stress under salinity in tomato seedlings. J. Plant Nutr. 41, 1234\u0026ndash;1245 (2018).\u003c/p\u003e\n\u003cp\u003eBates, L. S., Waldren, R. P., \u0026amp;Teare, I. D. Rapid determination of free proline for water-stress studies. Plant Soil 39, 205\u0026ndash;207 (1973).\u003c/p\u003e\n\u003cp\u003eChowdhury, M. A. H., Bhuiyan, M. S. R., Shah-E-Alam, M., et al. Evaluation of combining ability and genetic analysis for salinity tolerance in a 7 \u0026times; 7 F1 half-diallel population of groundnut (\u003cem\u003eArachis hypogaea L\u003c/em\u003e.). Discov. Plants 2, 327 (2025).\u003c/p\u003e\n\u003cp\u003eCunha, M. L. O., de Oliveira, L. C. A., Silva, V. M., Montanha, G. S., \u0026amp; Dos Reis, A. R. Selenium increases photosynthetic capacity, daidzein biosynthesis, nodulation and yield of peanut plants (\u003cem\u003eArachis hypogaea L\u003c/em\u003e.). Plant Physiol. Biochem. 190, 231\u0026ndash;239 (2022).\u003c/p\u003e\n\u003cp\u003eD\u0026rsquo;Autr\u0026eacute;aux, B. \u0026amp;Toledano, M. B. ROS as signalling molecules: mechanisms that generate specificity in ROS homeostasis. Nat. Rev. Mol. Cell Biol. 8, 813\u0026ndash;824 (2007).\u003c/p\u003e\n\u003cp\u003eDietz, K. J. Redox signal integration: from stimulus to networks and genes. Physiol. Plant. 151, 392\u0026ndash;405 (2014).\u003c/p\u003e\n\u003cp\u003eDjanaguiraman, M., Devi, D. N., Sheeba, J. A., et al. Selenium protects peanut seedlings from oxidative stress under salinity. Plant Physiol. Biochem. 43, 569\u0026ndash;577 (2005).\u003c/p\u003e\n\u003cp\u003eEl-Badri, A. M., Batool, M., Mohamed, I. A. A., Wang, Z., Wang, C., Tabl, K. M., et al. Mitigation of the salinity stress in rapeseed (\u003cem\u003eBrassica napus L\u003c/em\u003e.) productivity by exogenous applications of bio-selenium nanoparticles during the early seedling stage. Environ. Pollut. 310, 119815 (2022a).\u003c/p\u003e\n\u003cp\u003eFAO. The State of Food and Agriculture 2021: Making Agrifood Systems More Resilient. Food and Agriculture Organization, Rome (2021).\u003c/p\u003e\n\u003cp\u003eFeng, R., Wei, C., \u0026amp;Tu, S. The roles of selenium in protecting plants against abiotic stresses. Environ. Exp. Bot. 87, 58\u0026ndash;68 (2013).\u003c/p\u003e\n\u003cp\u003eFreeman, J. L., Zhang, L., Marcus, M. A., et al. Spatial imaging, speciation, and quantification of selenium in Stanleyapinnata plant tissue by X-ray absorption spectroscopy. Plant Physiol. 142, 124\u0026ndash;134 (2006).\u003c/p\u003e\n\u003cp\u003eGill, S. S. \u0026amp;Tuteja, N. Reactive oxygen species and antioxidant machinery in abiotic stress tolerance in crop plants. Plant Physiol. Biochem. 48, 909\u0026ndash;930 (2010).\u003c/p\u003e\n\u003cp\u003eGarc\u0026iacute;a-Locascio, E., Valenzuela, E. I., \u0026amp; Cervantes-Avil\u0026eacute;s, P. Impact of seed priming with selenium nanoparticles on germination and seedlings growth of tomato. Sci. Rep. 14, 6726 (2024).\u003c/p\u003e\n\u003cp\u003eHasanuzzaman, M., Bhuyan, M. H. M. B., Zulfiqar, F., et al. Reactive oxygen species and antioxidant defense in plants under abiotic stress: revisiting the role of selenium. Biol. Trace Elem. Res. 199, 1\u0026ndash;35 (2020).\u003c/p\u003e\n\u003cp\u003eHasanuzzaman, M., Nahar, K., Alam, M. M., et al. Physiological, biochemical, and molecular mechanisms of selenium-induced stress tolerance in plants. Front. Plant Sci. 5, 355 (2014).\u003c/p\u003e\n\u003cp\u003eHawrylak-Nowak, B. Selenium-mediated growth and stress tolerance in plants. Acta Physiol. Plant. 36, 2311\u0026ndash;2319 (2014).\u003c/p\u003e\n\u003cp\u003eHawrylak-Nowak, B. Selenium-induced changes in growth and antioxidant system of cucumber seedlings. Biol. Plant. 53, 541\u0026ndash;545 (2009).\u003c/p\u003e\n\u003cp\u003eHussain, S., Ahmed, S., Akram, W., Li, G., \u0026amp;Yasin, N. A. Selenium seed priming enhanced the growth of salt-stressed \u003cem\u003eBrassica rapa L\u003c/em\u003e. through improving plant nutrition and the antioxidant system. Front. Plant Sci. 13, 1050359 (2023).\u003c/p\u003e\n\u003cp\u003eIPCC. Climate Change 2022: Impacts, Adaptation and Vulnerability. Intergovernmental Panel on Climate Change, Geneva (2022).\u003c/p\u003e\n\u003cp\u003eIqbal, M., Ashraf, M., \u0026amp; Jamil, A. Alleviation of salt stress in tomato (\u003cem\u003eSolanum lycopersicum\u003c/em\u003e) by selenium and proline. Pak. J. Bot. 47, 45\u0026ndash;54 (2015).\u003c/p\u003e\n\u003cp\u003eJiang, C., Ma, L., et al. Selenium enhances salt tolerance in plants through modulation of proline metabolism and antioxidative defense. Plant Soil 418, 345\u0026ndash;360 (2017).\u003c/p\u003e\n\u003cp\u003eJulkowska, M. M. \u0026amp;Testerink, C. Tuning plant signaling and growth to survive salt. Trends Plant Sci. 20, 586\u0026ndash;594 (2015).\u003c/p\u003e\n\u003cp\u003eKhan, Z., Thounaojam, T. C., Chowdhury, D., \u0026amp;Upadhyaya, H. The role of selenium and nano selenium on physiological responses in plant: a review. Plant Growth Regul. 100, 409\u0026ndash;433 (2023).\u003c/p\u003e\n\u003cp\u003eMensah, J. T., Oppong, S., \u0026amp;Osei, M. Effects of salinity on groundnut germination and early growth. Int. J. Agric. Biol. 8, 857\u0026ndash;861 (2006).\u003c/p\u003e\n\u003cp\u003eMunns, R. \u0026amp; Tester, M. Mechanisms of salinity tolerance. Annu. Rev. Plant Biol. 59, 651\u0026ndash;681 (2008).\u003c/p\u003e\n\u003cp\u003ePilon-Smits, E. A. \u0026amp; Quinn, C. F. Selenium metabolism in plants and its impact on stress tolerance. J. Plant Nutr. 33, 1245\u0026ndash;1260 (2010).\u003c/p\u003e\n\u003cp\u003ePilon-Smits, E. A., Quinn, C. F., \u0026amp; Schiavon, M. Selenium metabolism in plants. Plant Sci. 196, 1\u0026ndash;12 (2009).\u003c/p\u003e\n\u003cp\u003eQadir, M., Quill\u0026eacute;rou, E., Nangia, V., et al. Economics of salt-induced land degradation and restoration. Nat. Resour. Forum 38, 282\u0026ndash;295 (2014).\u003c/p\u003e\n\u003cp\u003eRady, M. M., Hemida, K. A., \u0026amp;Hemida, S. Selenium and salt stress interactions in crop plants: effects on growth and physiology. Environ. Sci. Pollut. Res. 27, 3456\u0026ndash;3470 (2020).\u003c/p\u003e\n\u003cp\u003eRios, J. J., Gallardo, M., \u0026amp; Romero, L. Selenium modulates proline metabolism in \u003cem\u003eBrassica\u003c/em\u003e species under stress. Plant Physiol. Biochem. 46, 497\u0026ndash;503 (2008).\u003c/p\u003e\n\u003cp\u003eSchiavon, M. \u0026amp;Pilon-Smits, E. A. Selenium in plants: understanding the dual nature of Se for plant physiology and human nutrition. Front. Plant Sci. 8, 978 (2017).\u003c/p\u003e\n\u003cp\u003eSchiavon, M., Pilon-Smits, E., \u0026amp;Wangeline, A. J. Selenium biofortification: uptake, metabolism, and benefits in plants. Plant Biol. 18, 1\u0026ndash;10 (2016).\u003c/p\u003e\n\u003cp\u003eSors, T. G., Ellis, D. R., \u0026amp; Salt, D. E. Selenium uptake, translocation, assimilation, and metabolic fate in plants. Photosynth. Res. 86, 373\u0026ndash;389 (2005).\u003c/p\u003e\n\u003cp\u003eSzabados, L. \u0026amp;Savour\u0026eacute;, A. Proline: a multifunctional amino acid. Trends Plant Sci. 15, 89\u0026ndash;97 (2010).\u003c/p\u003e\n\u003cp\u003eTerry, N., Zayed, A. M., de Souza, M. P., \u0026amp;Tarun, A. S. Selenium in higher plants. Annu. Rev. Plant Physiol. Plant Mol. Biol. 51, 401\u0026ndash;432 (2000).\u003c/p\u003e\n\u003cp\u003eUlhassan, Z., Ashraf, M., \u0026amp; Ali, S. Selenium priming improves salinity tolerance in rice seedlings. Plant Physiol. Biochem. 145, 31\u0026ndash;41 (2019).\u003c/p\u003e\n\u003cp\u003eUpadhyaya, H. D., Bramel, P. J., Singh, S., \u0026amp; Ortiz, R. Developing groundnut cultivars for marginal environments: advances and challenges. Crop Sci. 54, 1243\u0026ndash;1253 (2014).\u003c/p\u003e\n\u003cp\u003eVan Hoewyk, D. Selenium-induced stress and toxicity in plants. Physiol. Plant. 149, 725\u0026ndash;739 (2013).\u003c/p\u003e\n\u003cp\u003eVerbruggen, N. \u0026amp;Hermans, C. Proline accumulation in plants: a review. Plant Biol. 10, 305\u0026ndash;320 (2008).\u003c/p\u003e\n\u003cp\u003eWhite, P. J. Selenium accumulation and metabolism in plants: consequences for human health. J. Exp. Bot. 67, 3703\u0026ndash;3715 (2016).\u003c/p\u003e\n\u003cp\u003eZiegler, J. \u0026amp; Fageria, N. K. Seed priming strategies for enhanced stress tolerance in crops: a review. Agron. J. 113, 1\u0026ndash;15 (2021).\u003c/p\u003e\n\u003cp\u003eZhu, J. K. Plant salt tolerance. Trends Plant Sci. 6, 66\u0026ndash;71 (2001).\u003c/p\u003e\n\u003cp\u003eZhu, J. K. Regulation of ion homeostasis under salt stress. Curr. Opin. Plant Biol. 5, 441\u0026ndash;445 (2002).\u003c/p\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"discover-plants","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"","sideBox":"Learn more about [Discover Plants](https://link.springer.com/journal/44372)","snPcode":"44372","submissionUrl":"https://submission.springernature.com/new-submission/44372/3","title":"Discover Plants","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Discover Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Selenium priming, Arachis hypogaea, Salinity stress, Seed germination, Early seedling growth, Hormesis","lastPublishedDoi":"10.21203/rs.3.rs-8605366/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8605366/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eSoil salinity as a result of global warming and poor agro-cultural practices poses a significant challenge to food production. Selenium (Se) has emerged as a promising micronutrient capable of mitigating abiotic stress in plants by reducing reactive oxygen species and supporting cellular metabolism. This study investigated the effects of selenium seed priming on germination and early seedling development of an \u003cem\u003eArachis hypogaea\u003c/em\u003e L. landrace under a gradient of saline conditions. Seeds were primed with selenium at five concentrations (0, 1.5, 2.5, 5, and 10 mg L⁻¹) for three durations (3, 6, and 9 h) and sown in Petri dishes containing sodium chloride solutions ranging from 0 to 7 g L⁻¹. Germination indices—including germination percentage, mean germination time, germination rate index, and germination velocity—along with seedling growth parameters and biochemical contents were evaluated. A composite Z-score integrating all measured parameters was used to rank the most effective selenium treatment at each salinity level. Selenium treatments exhibited concentration-dependent responses, with lower to moderate concentrations showing optimal or suboptimal effects, while higher concentrations induced inhibitory effects, indicating a clear hormetic response. These findings demonstrate that selenium seed priming at appropriate concentrations and durations represents a simple and cost-effective strategy for enhancing peanut establishment under saline soil conditions.\u003c/p\u003e","manuscriptTitle":"Effect of Selenium Priming duration on Germination and Early Seedling Development of Arachis hypogaea L. 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