Combined Effects of Mechanical Scarification, Hormonal Treatments, and Hydration Optimization on Germination and Early Seedling Growth of Argania spinosa under Plastic Tunnel Conditions

Combined Effects of Mechanical Scarification, Hormonal Treatments, and Hydration Optimization on Germination and Early Seedling Growth of Argania spinosa under Plastic Tunnel Conditions | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Combined Effects of Mechanical Scarification, Hormonal Treatments, and Hydration Optimization on Germination and Early Seedling Growth of Argania spinosa under Plastic Tunnel Conditions Ahmed M. Eed, Abdullah H. Al-hajj This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8933092/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Argania spinosa (L.) is an ecologically and economically important tree species native to North Africa; however, its large-scale propagation is constrained by low and irregular germination due primarily to strong physical dormancy imposed by a hard, impermeable seed coat. This study aimed to systematically evaluate and optimize dormancy-breaking treatments to enhance germination and early seedling growth under plastic tunnel conditions. Two successive experiments were conducted using mechanically scarified seeds to eliminate physical dormancy. In Experiment I, scarified seeds were soaked for a fixed duration in different plant growth regulators (PGRs) including gibberellic acid (GA₃), naphthalene acetic acid (NAA), and indole-3-acetic acid (IAA), alongside hot water and tap water treatments. Based on the most promising treatment, Experiment II further optimized soaking duration and germination substrate. Germination percentage, plant height, and leaf number were assessed at 30 and 60 days after sowing. The results indicate that, in Experiment I, PGRs did not significantly improve germination compared with simple tap water soaking, which achieved the highest germination percentage (33.30%). However, higher concentrations of GA 3 significantly enhanced vegetative growth. In Experiment II, extending soaking duration from 10 minutes to 3 hours dramatically increased germination to 100% and significantly improved seedling development. Substrate type also affected emergence, with cardboard-based media achieving 73.30% germination compared to 13.30% in sawdust. These indicate that prolonged hydration following mechanical scarification is more effective for maximizing germination than short-duration hormonal treatments. The optimized protocol including mechanical scarification followed by prolonged soaking in tap water and sowing in a well-aerated substrate, offers a simple, low-cost, and scalable strategy for argan nursery production and restoration programs in arid and semi-arid regions. Argania spinosa seed dormancy mechanical scarification hydration optimization gibberellic acid germination percentage Figures Figure 1 1. Introduction Argan ( Argania spinosa (L.) Skeels) is a multipurpose tree species native to North Africa and highly adapted to arid and semi-arid environments (El Aboudi et al., 2023; Zahidi et al., 2024). The species plays a pivotal ecological role in stabilizing fragile dryland ecosystems by reducing soil erosion, limiting desertification, and enhancing biodiversity and ecosystem resilience (Msanda et al., 2022; Aboudrare et al., 2025). Beyond its ecological importance, argan holds substantial socioeconomic value due to its high-quality oil, which is extensively utilized in the food, cosmetic, and pharmaceutical industries, making it one of the most economically significant forest tree species in dry regions (Morton & Voss, 1987; Lybbert et al., 2011; Charrouf & Guillaume, 2022; El Mouden et al., 2023). Despite its ecological and economic relevance, large-scale propagation of argan remains constrained by poor and inconsistent natural regeneration. Low germination rates and slow seedling establishment represent major bottlenecks in nursery production systems. One of the principal constraints is seed dormancy, which in argan is predominantly physical dormancy imposed by a thick, hard, and water-impermeable seed coat that restricts imbibition, gas exchange, and embryo expansion (Bani-Aameur & Alouani, 1999; Alouani & Bani-Aameur, 2004). Physical dormancy is common among woody and desert-adapted species and typically requires disruption of the seed coat barrier to permit water uptake and initiate metabolic reactivation (Baskin & Baskin, 2014; Bewley et al., 2013). In addition to physical dormancy, evidence suggests that a physiological component may also occur in argan seeds, as improved germination has been observed following cold stratification or gibberellic acid (GA₃) application (Bani-Aameur & Alouani, 1999; El Qadmi et al., 2023; Maamar Kouadri et al., 2024). Physiological dormancy involves biochemical constraints within the embryo that inhibit germination even after adequate hydration (Finch-Savage & Leubner-Metzger, 2006). Consequently, untreated argan seeds often exhibit delayed, irregular, and low germination, resulting in prolonged nursery cycles, reduced seedling uniformity, and increased production costs (Maamar Kouadri et al., 2024). Breaking seed dormancy through appropriate pre-sowing treatments is therefore essential for improving germination percentage, uniformity, and seedling vigor. Mechanical scarification, hot water treatment, and prolonged soaking are widely used to overcome physical dormancy in hard-coated seeds by enhancing seed coat permeability (Bewley et al., 2013). Once physical dormancy is alleviated, residual physiological constraints may require additional stimulation. Plant growth regulators (PGRs), particularly gibberellins (GA₃) and auxins such as indole-3-acetic acid (IAA) and naphthalene acetic acid (NAA), have been reported to promote germination and early seedling growth. In many woody species, a sequential approach combining mechanical scarification to break physical dormancy followed by hormonal treatments to address physiological dormancy has significantly improved germination performance (Baskin & Baskin, 2014). However, treatment efficacy is highly species-specific and influenced by concentration, soaking duration, and environmental conditions. Although previous studies have explored dormancy-breaking methods in argan, comparative evaluations of hormonal treatments applied after physical dormancy removal, alongside simple hydration-based approaches under protected nursery conditions, remain limited. In particular, there is insufficient information regarding cost-effective and easily adoptable techniques suitable for large-scale propagation under arid and semi-arid environments similar to those of Yemen and comparable regions. Comparable improvements in germination and early seedling establishment following optimized physical and hydration-based pre-sowing treatments have been documented in several woody and horticultural species (Eed & Yahya, 2021; Eed & Al-Hajj, 2023; Eed et al., 2023). Nevertheless, the relative effectiveness of hydration versus hormonal stimulation in argan following mechanical scarification remains unclear. Accordingly, this study was designed to systematically evaluate the effectiveness of mechanical scarification combined with hormonal and hydration treatments on germination and early seedling growth of argan under plastic tunnel conditions. By adopting a stepwise experimental approach and optimizing the most promising treatment, the study aims to identify a practical, low-cost, and scalable propagation protocol. The specific objectives were to: To evaluate the effects of different concentrations of GA₃ and selected auxins (IAA and NAA) on germination and early vegetative growth of mechanically scarified argan seeds. To compare hormonal treatments with hydration-based pre-sowing treatments (hot water and tap water soaking) in improving germination performance and seedling vigor under nursery conditions. To identify and optimize a practical propagation protocol by refining soaking duration and substrate type to maximize germination efficiency and early seedling development. 2. Materials and Methods 2.1 Research Site and Seed Source The study was conducted at the nurseries of the Organic Yemen Foundation, Sana'a, Yemen, through two sequential experiments designed to progressively optimize argan seed germination. The second experiment was structured based on the outcomes of the first experiment to further refine and improve germination performance. Argan seeds were obtained from Algeria through Eng. Abdelhakim Ouzzane, Ministry of Agriculture, Algeria. 2.2 Preliminary Experiments Preliminary trials were conducted to identify suitable germination procedures for argan seeds. These included: (i) sowing intact embryos on moist tissue paper for 72 h, (ii) sowing mechanically scarified seeds without further treatment, and (iii) sowing seeds with intact seed coats in a standard rooting medium under plastic tunnel conditions. None of these approaches resulted in a significant improvement in germination percentage (data not shown). Therefore, a structured experimental approach was developed to systematically address both physical and physiological dormancy constraints (Experiment I), followed by further optimization of the most promising treatment (Experiment II). 2.3 Experiment I: Sequential Dormancy Removal and Growth Stimulation Experiment I was conducted inside plastic tunnels at the Organic Yemen nursery in October 2021. Seeds were sown in seedling trays containing a rooting medium composed of sand, clay soil, and perlite at a 1:1:1 (v/v/v) ratio. Irrigation was applied manually every three days, or as needed, to maintain adequate moisture while preventing waterlogging and fungal contamination. This experiment was designed to sequentially remove physical dormancy through scarification, followed by evaluation of hormonal and thermal treatments aimed at overcoming possible residual physiological dormancy and stimulating early seedling growth. Germination and vegetative parameters were recorded at 30 and 60 days after sowing. 2.3.1 Pre-treatment for Breaking Physical Dormancy To overcome the physical dormancy imposed by the hard, impermeable seed coat, seeds were subjected to a two-step scarification procedure. First, seeds were soaked in tap water for three days to soften the seed coat. Subsequently, mechanical scarification was carefully performed using manual tools; pliers and a hammer on a stone surface to crack the seed coat without damaging the embryo. Approximately one-third to one-half of the seed coat was removed, allowing direct exposure of the embryo prior to subsequent treatments (Fig. 1a-1d). 2.3.2 Hormonal and Thermal Treatments for Overcoming Physiological Dormancy After scarification, seeds were subjected to the following treatments for 10 min to address potential physiological dormancy and stimulate germination: T1: GA₃ at 4000 ppm T2: GA₃ at 3000 ppm T3: GA₃ at 2000 ppm T4: GA₃ at 1000 ppm T5: NAA at 1000 ppm T6: IAA at 1000 ppm T7: Warm water (≈30°C) T8: Tap water (control) This design allowed direct comparison between hormonal stimulation, mild thermal exposure, and simple hydration following scarification. 2.3.3 Measured Parameters The following parameters were evaluated: 2.3.3.1 Germination percentage (%) 2.3.3.2 Seedling height (cm) 2.3.3.3 Number of leaves per plant 2.3.4 Experimental Design and Statistical Analysis The experiment was arranged in a completely randomized design (CRD) with eight treatments. Each treatment consisted of nine seeds distributed into three replicates (three seeds per replicate). Data were subjected to analysis of variance (ANOVA) using the F-test. Treatment means were separated using Fisher’s Least Significant Difference (LSD) test at the 5% probability level. Germination percentage data were square-root transformed prior to analysis to satisfy normality assumptions. Statistical analyses were performed using OPSTAT software (CCS Haryana Agricultural University, Hisar, India). 2.4 Experiment II: Optimization of Hydration Duration and Growing Substrate Based on the results of Experiment I, the control treatment (T8: soaking scarified seeds in tap water for 10 min) produced the highest germination percentage (33.30%). Notably, this indicated that simple hydration following scarification was more effective than exogenous hormonal application under the tested conditions. Experiment II was therefore designed to further optimize this response by modifying soaking duration and evaluating alternative germination substrates. The experiment was conducted in February 2022. The following treatments were evaluated: T9: Soaking scarified seeds in tap water for 10 min, followed by sowing in cardboard tea pads T10: Soaking scarified seeds in tap water for 10 min, followed by sowing in sawdust T11: Soaking scarified seeds in tap water for 3 h, followed by sowing in the standard rooting medium used in Experiment I. Germination and vegetative parameters were recorded at 30 and 60 days after sowing. 2.4.1 Experimental Design and Statistical Analysis The experiment followed a completely randomized design (CRD) identical to Experiment I. Each treatment consisted of 15 seeds arranged into three replicates (five seeds per replicate). The same measured parameters, data transformation procedures, and statistical analysis methods were applied. 3. Results 3.1 Experiment I: Effects of Plant Growth Regulators and Hydration on Germination and Early Growth of Scarified Argan Seeds 3.1.1 Germination Percentage At 30 days after sowing, germination percentage ranged from 11.10% to 33.30% across treatments (Table 1 ). The highest germination (33.30%) was recorded in seeds soaked in tap water for 10 min (T8), followed by GA₃ at 1000 ppm (T4) and auxin treatments (T5 and T6), each producing 22.20%. In contrast, higher GA₃ concentrations (T1–T3) and warm water treatment (T7) resulted in lower germination (11.10%). However, differences among treatments were not statistically significant. A similar pattern was observed at 60 days (Table 2 ), with T8 maintaining the highest germination percentage (33.30%), while higher GA₃ concentrations and warm water treatment remained comparatively low (11.10%). Germination differences were again statistically non-significant. These results indicate that short-duration exogenous PGRs application did not enhance germination beyond simple hydration following scarification. Table 1 Effects of PGRs and Water Treatments on Germination and Early Seedling Growth of Mechanically Scarified Argan Seeds 30 Days after Sowing under Plastic Tunnel Conditions Treatments Germination %* Plant Height (cm)* No of leaves/plant* T1: Soaking cracked seeds in a GA₃ @ 4000 ppm for 10 min 11.10 (2.61) NS 6.66 a 8.33 b T2: Soaking cracked seeds in a GA₃ @ 3000 ppm for 10 min 11.10 (2.61) NS 4.66 b 11.66 a T3: Soaking cracked seeds in a GA₃ @ 2000 ppm for 10 min 11.10 (2.61) NS 2.00 d 3.33 de T4: Soaking cracked seeds in a GA₃ @ 1000 ppm for 10 min 22.20 (4.23) NS 2.20 d 2.33 de T5: Soaking cracked seeds in an NAA @ 1000 ppm for 10 min 22.20 (3.40) NS 2.33 d 4.66 c T6: Soaking cracked seeds in an IAA @ 1000 ppm for 10 min 22.20 (4.23) NS 2.00 d 2.00 e T7: Soaking cracked seeds in hot water for 10 min 11.10 (2.61) NS 2.83 cd 2.00 e T8: Soaking cracked seeds in tap water for 10 min 33.30 (5.85) NS 2.33 d 2.33 de * Within columns, mean values followed by different superscript letters differ significantly (p < 0.05) as determined by Fisher’s least significant difference (LSD) test. Values in parentheses are square-root transformed. 3.1.2 Plant Height Significant differences in seedling height were observed at both evaluation periods. At 30 days, GA₃ at 4000 ppm produced the tallest seedlings (6.66 cm), followed by GA₃ at 3000 ppm (4.66 cm), whereas other treatments resulted in comparatively shorter seedlings (2.00–2.83 cm) (Table 1 ). At 60 days, the same trend persisted, with GA₃ at 4000 ppm and 3000 ppm producing the greatest plant heights (8.66 and 6.66 cm, respectively) (Table 2 ). Seedlings from other treatments generally remained below 4 cm. Table 2 Effects of Plant Growth Regulator and Water Treatments on Germination and Early Seedling Growth of Mechanically Scarified Argan Seeds 60 Days after Sowing under Plastic Tunnel Conditions Treatments Germination %* Plant Height (cm)* No of leaves/plant* T1: Soaking cracked seeds in a GA₃ @ 4000 ppm for 10 min 11.10 (2.61) NS 8.66 a 11.33 b T2: Soaking cracked seeds in a GA₃ @ 3000 ppm for 10 min 11.10 (2.61) NS 6.66 b 14.66 a T3: Soaking cracked seeds in a GA₃ @ 2000 ppm for 10 min 11.10 (2.61) NS 2.66 d 4.33 d T4: Soaking cracked seeds in a GA₃ @ 1000 ppm for 10 min 22.20 (4.23) NS 2.83 d 3.33 e T5: Soaking cracked seeds in an NAA @ 1000 ppm for 10 min 22.20 (4.23) NS 3.33 cd 4.66 cd T6: Soaking cracked seeds in an IAA @ 1000 ppm for 10 min 22.20 (4.23) NS 3.16 cd 2.33 f T7: Soaking cracked seeds in hot water for 10 min 11.10 (2.61) NS 3.83 c 2.00 f T8: Soaking cracked seeds in tap water for 10 min 33.30 (2.85) NS 2.66 d 2.66 ef * Within columns, mean values followed by different superscript letters differ significantly (p < 0.05) as determined by Fisher’s least significant difference (LSD) test. Values in parentheses are square-root transformed. 3.1.3 Number of Leaves per Plant Leaf production differed significantly among treatments at both observation periods. At 30 days, GA₃ at 3000 ppm produced the highest leaf number (11.66 leaves plant⁻¹), followed by GA₃ at 4000 ppm (8.33 leaves plant⁻¹), while warm water and IAA treatments recorded the lowest values (Table 1 ). At 60 days, GA₃ at 3000 ppm again resulted in the highest leaf number (14.66 leaves plant⁻¹), followed by GA₃ at 4000 ppm (11.33 leaves plant⁻¹) (Table 2 ). Hydration-only and auxin treatments produced comparatively fewer leaves. Overall, while GA₃ significantly enhanced vegetative growth, it did not improve germination percentage relative to simple tap water soaking. 3.2 Experiment II: Optimization of Hydration Duration and Germination Substrate Results from Experiment I demonstrated that simple hydration after scarification (T8) produced the highest germination percentage, whereas PGR treatments did not confer additional benefits. Therefore, Experiment II focused on optimizing hydration duration and evaluating alternative germination substrates to further improve emergence and seedling establishment. 3.2.1 Germination Percentage Marked and statistically significant differences were observed among treatments (Table 3 ). At 30 days after sowing, soaking scarified seeds in tap water for 3 h (T11) resulted in 100% germination, significantly exceeding all other treatments. Soaking for 10 min followed by sowing in cardboard tea pads (T9) achieved 73.30% germination, whereas sowing in sawdust (T10) resulted in only 13.30%. The same pattern was maintained at 60 days (Table 4 ), with T11 sustaining 100% germination, followed by T9 (73.30%), while T10 remained significantly lower (13.30%). This represents a threefold increase compared with the best treatment in Experiment I. Table 3 Effect of Water Treatments on Germination and Early Seedling Growth of Mechanically Scarified Argan Seeds 30 Days after Sowing under Plastic Tunnel Conditions Treatments Germination %* Plant Height (cm)* No of leaves/plant* T9: Soaking scarified seeds in tap water for 10 min, followed by planting in cardboard tea pads 73.30 (8.60) b 2.60 a 2.66 a T10: Soaking scarified seeds in tap water for 10 min, followed by planting in sawdust. 13.30 (3.73) c 0.43 b 0.00 c T11: Soaking scarified seeds in tap water for 3 hr 100 (10.05) a 1.16 b 1.48 b * Within columns, mean values followed by different superscript letters differ significantly (p < 0.05) as determined by Fisher’s least significant difference (LSD) test. Values in parentheses are square-root transformed. 3.2.2 Plant Height Significant differences in seedling height were observed among treatments. At 30 days, T9 produced the tallest seedlings (2.60 cm), followed by T11 (1.16 cm), while T10 resulted in minimal growth (0.43 cm) (Table 3 ). By 60 days, T11 produced the greatest plant height (7.14 cm), followed by T9 (4.38 cm), whereas T10 remained significantly inferior (0.66 cm) (Table 4 ). Table 4 Effect of Water Treatments on Germination and Early Seedling Growth of Mechanically Scarified Argan Seeds 60 Days after Sowing under Plastic Tunnel Conditions Treatments Germination %* Plant Height (cm)* No of leaves/plant* T9: Soaking scarified seeds in tap water for 10 min, followed by planting in cardboard tea pads 73.30 (8.55) a 4.38 b 8.66 a T10: Soaking scarified seeds in tap water for 10 min, followed by planting in sawdust. 13.30 (3.38) b 0.66 c 2.00 b T11: Soaking scarified seeds in tap water for 3 hr 100.00 (10.05) a 7.14 a 11.96 a * Within columns, mean values followed by different superscript letters differ significantly (p < 0.05) as determined by Fisher’s least significant difference (LSD) test. Values in parentheses are square-root transformed. 3.2.3 Number of Leaves per Plant Leaf production followed a trend similar to plant height. At 30 days, T9 produced the highest leaf number (2.66 leaves plant⁻¹), followed by T11 (1.48 leaves plant⁻¹), while no leaf development was observed under T10 (Table 3 ). At 60 days, both T11 and T9 significantly enhanced leaf production (11.96 and 8.66 leaves plant⁻¹, respectively), compared with only 2.00 leaves under T10 (Table 4 ). 4. Discussion Successful domestication and large-scale propagation of Argania spinosa (L.) Skeels remain constrained by low and inconsistent seed germination, largely attributed to strong physical dormancy imposed by the hard seed coat (Baskin & Baskin, 2014 ; El Aboudi et al., 2017). Physical dormancy in woody species typically restricts water uptake and gas exchange, thereby delaying embryo activation (Baskin & Baskin, 2014 ; Bewley et al., 2013 ). In the present study, a stepwise experimental strategy was adopted to systematically identify and optimize effective dormancy-breaking treatments under plastic tunnel conditions. Preliminary trials (data not shown) indicated poor germination under conventional sowing approaches, which justified the implementation of mechanical scarification followed by hormonal and hydration treatments (Experiment I). Based on these outcomes, Experiment II refined the most promising treatment by optimizing soaking duration and substrate type. This progressive design allowed the development of a highly efficient, low-cost propagation protocol. Importantly, the findings demonstrate that once physical dormancy is disrupted, hydration—rather than hormonal stimulation—is the principal determinant of germination success in argan. 4.1 Plant Growth Regulator Effects on Germination of Scarified Argan Seeds In Experiment I, germination percentage remained statistically non-significant among most treatments, including all concentrations of GA₃, NAA, and IAA. These results suggest that exogenous hormonal application following scarification does not substantially enhance germination beyond hydration alone (Jatana et al., 2024 ; Wu et al., 2023 ). Gibberellic acid (GA₃) is well known to stimulate germination in seeds exhibiting physiological dormancy by promoting α-amylase production, endosperm weakening, and embryo elongation (Bewley et al., 2013 ; Taiz et al., 2015 ; Liu et al., 2022 ; Chang et al., 2024 ). However, its limited effect in this study indicates that argan seeds likely lack a strong physiological dormancy component once the mechanical barrier is removed. Similar observations have been reported in hard-coated woody species where GA₃ improved germination only when physiological constraints were present, but showed limited effect when dormancy was primarily physical (Baskin & Baskin, 2014 ; Hartmann et al., 2018 ; Rana et al., 2023 ; El Qadmi et al., 2023 ). Therefore, our results reinforce that seed coat impermeability is the dominant dormancy mechanism in argan. 4.2 Growth-promoting effects of GA₃ and auxins Although hormonal treatments did not significantly increase germination percentage, GA₃ at higher concentrations (3000–4000 ppm) significantly enhanced plant height and leaf number (Liu et al., 2022 ; Jatana et al., 2024 ). Gibberellins are widely documented to promote stem elongation, cell division, and leaf expansion through stimulation of cell wall extensibility and meristem activity (Davies, 2010 ; Taiz et al., 2015 ; Zhang et al., 2022 ; Chen et al., 2023 ). Similarly, auxins (IAA and NAA) slightly improved early vegetative growth (Singh et al., 2023 ; Wang et al., 2022 ). Auxins regulate cell elongation, vascular differentiation, and apical dominance, thereby enhancing early seedling vigor (Davies, 2010 ; Li et al., 2023 ). These findings indicate that plant growth regulators may be beneficial for post-germination growth enhancement, even though they are not essential for dormancy release in argan. This distinction between germination control and vegetative growth promotion has practical implications for nursery management (Jatana et al., 2024 ). 4.3 Superiority of water soaking for promoting germination A key finding of Experiment I was that soaking scarified seeds in tap water for 10 minutes consistently produced the highest germination percentage. Notably, this simple hydration treatment outperformed both hormonal applications and hot water soaking (Rana et al., 2023 ; Jatana et al., 2024 ). Water uptake (imbibition) is the first critical step in germination and initiates metabolic reactivation, mitochondrial repair, enzyme synthesis, and radicle protrusion (Bewley et al., 2013 ; Liu et al., 2022 ; Chen et al., 2023 ). Enhanced hydration improves oxygen diffusion and softens residual seed coat tissues, facilitating embryo expansion (Finch-Savage & Leubner-Metzger, 2006 ; Zhang et al., 2023 ). In contrast, excessive thermal exposure may damage embryo tissues or induce secondary stress responses, particularly in species not adapted to fire-related dormancy release (Baskin & Baskin, 2014 ). Similar results have been documented in other hard-seeded tree species, where moderate hydration treatments proved safer and more effective than chemical or thermal scarification (Baskin & Baskin, 2014 ; Hartmann et al., 2018 ; Rana et al., 2023 ; El Qadmi et al., 2023 ). Thus, the present study demonstrates that hydration is the primary activating factor once mechanical resistance is reduced. Thus, the present study demonstrates that hydration is the primary activating factor once mechanical resistance is reduced. 4.4 Optimization through soaking duration and substrate modification Because short-duration soaking yielded promising results, Experiment II investigated prolonged soaking and substrate effects. Extending soaking duration to 3 hours resulted in 100% germination (Jatana et al., 2024 ; Rana et al., 2023 ). Extended soaking likely enables complete water penetration through partially scarified tissues, accelerating metabolic activation, enzyme synthesis, and uniform radicle emergence (Finch-Savage & Leubner-Metzger, 2006 ; Bewley et al., 2013 ; Liu et al., 2022 ; Chen et al., 2023 ). Improved germination rate and uniformity following optimized hydration periods have been widely reported in woody and desert-adapted species (Hartmann et al., 2018 ; El Qadmi et al., 2023 ). Substrate type significantly influenced outcomes. Cardboard tea pads promoted higher germination and seedling growth compared with sawdust. Successful germination requires an optimal water–air balance in the rooting medium (Landis et al., 2014 ; Abad et al., 2023 ). Excessively compact or nutrient-immobilizing substrates, such as undecomposed sawdust, may restrict oxygen diffusion and nutrient availability (Landis et al., 2014 ; Kumar et al., 2022 ). The integration of optimized hydration duration with an appropriate substrate represents a practical refinement that maximizes germination efficiency. 4.5 Implications and novelty for argan propagation The present study establishes a clear and operational propagation protocol for Argania spinosa under protected nursery conditions. Once physical dormancy was eliminated through mechanical scarification, prolonged hydration in tap water proved sufficient to achieve near-complete germination (100%) without the need for exogenous plant growth regulators. The principal novelty of this work lies in demonstrating that optimization of hydration following scarification, rather than hormonal supplementation, is the critical determinant of successful germination. While previous studies have emphasized gibberellic acid or chemical treatments to enhance germination, the present findings clarify that such inputs are not essential once the mechanical barrier imposed by the seed coat is removed. This provides both physiological insight—confirming that dormancy in argan is primarily physical—and a directly applicable, low-cost nursery technique. From a practical standpoint, the proposed protocol is economically feasible, environmentally sustainable, and easily transferable to large-scale propagation systems in arid and semi-arid regions, thereby supporting domestication, conservation, and reforestation programs. 5. Conclusion 5.1 This study confirms that dormancy in Argania spinosa seeds is primarily physical and imposed by the hard seed coat. Mechanical scarification effectively removes this constraint, and adequate hydration is the key factor controlling successful germination. 5.2 Prolonged soaking of scarified seeds in tap water for three hours resulted in 100% germination, whereas exogenous plant growth regulators did not significantly enhance germination percentage, although gibberellic acid promoted subsequent vegetative growth. 5.3 The optimized protocol—mechanical scarification followed by controlled hydration and appropriate substrate selection—provides a simple, economical, and scalable method for argan nursery production and restoration initiatives in arid environments. Declarations Ethics approval and consent to participate Not applicable. This study did not involve human participants or vertebrate animals. Consent for publication Not applicable. Funding This research received no specific grant from funding agencies in the public, commercial, or not-for-profit sectors. Competing interests The authors declare that they have no competing interests. Author Contribution AME designed the study, conducted Experiment I, performed data analysis, and wrote the main manuscript text. AHA conducted Experiment II and contributed to data collection and interpretation. Both authors reviewed and approved the final manuscript. Data Availability The datasets generated and/or analyzed during the current study are available from the corresponding author, Ahmed M. Eed, on reasonable request. References Abad, M., Noguera, P., & Bures, S. (2023). Growing media properties and their influence on seed germination and seedling development. Horticulturae, 9, 642. https://doi.org/10.3390/horticulturae9060642 Aboudrare, A., El Mousadik, A., & Msanda, F. (2025). Ecological services and climate resilience of Argania spinosa in semi-arid ecosystems. Plants, 14, Article 664. Alouani, M., & Bani-Aameur, F. (2004). Germination characteristics of Argania spinosa seeds. 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Influence of specific treatments on germination and growth characteristics of mango ( Mangifera indica L.) seeds. Arabian Journal for Scientific Research. Eed, A. M., & Yahya, H. (2021). Germination and growth of moringa ( Moringa oleifera ) seeds in peat moss medium affected by dipping, temperature, and gibberellic acid treatments. Al-Baydha University Journal. Eed, A. M., Al-Hajj, A. H. A., Ebrahim, F., & Alousali, T. (2023). The effect of chemical and physical treatments on the germination of avocado ( Persea americana ) seeds. Sa’ada University Journal. El Aboudi, A., et al. (2023). Drought adaptation strategies and ecophysiological responses of Argania spinosa in arid Morocco. Forests, 14, 1987. El Qadmi, I., Lagram, K., Benchekroun, M., El Boullani, R., & Serghini, M. A. (2023). Improvement of germination, rooting and elongation capacities in vitro of four argan ( Argania spinosa ) genotypes. International Journal of Agriculture and Biology, 29 (2), 89–96. El Qadmi, Y., et al. (2023). Seed dormancy and germination responses of Argania spinosa under different pre-sowing treatments. Forests, 14, Article 1987. Finch-Savage, W. E., & Leubner-Metzger, G. (2006). Seed dormancy and the control of germination. New Phytologist, 171 (3), 501–523. https://doi.org/10.1111/j.1469-8137.2006.01787.x Hartmann, H. T., Kester, D. E., Davies, F. T., Jr., & Geneve, R. L. (2018). Plant propagation: Principles and practices (9th ed.). Pearson. Jatana, B. S., Grover, S., Ram, H., & Baath, G. S. (2024). Seed priming: molecular and physiological mechanisms underlying stress tolerance. Agronomy, 14(12), 2901. https://doi.org/10.3390/agronomy14122901 Kumar, A., Singh, R., & Meena, M. (2022).Substrate physical properties affecting aeration and nutrient dynamics in nursery media. Plants, 11, 2984. https://doi.org/10.3390/plants11222984 Landis, T. D., Dumroese, R. K., & Haase, D. L. (2014). The container tree nursery manual: Seedling processing, storage, and outplanting (Vol. 7). USDA Forest Service. Li, H., Sun, Y., & Wang, X. (2023). Auxin signaling in plant growth and vascular differentiation: Recent advances. Plants, 12, 2145. https://doi.org/10.3390/plants12112145 Liu, Y., Zhang, R., & Chen, H. (2022). Hormonal regulation and metabolic activation during seed germination. Plants, 11, 3158. https://doi.org/10.3390/plants11223158 Lybbert, T. J., Aboudrare, A., Chaloud, D., Magnan, N., & Nash, M. (2011). Booming markets for Moroccan argan oil appear to benefit some rural households while threatening the sustainability of the argan forest. Proceedings of the National Academy of Sciences, 108 (34), 13963–13968. https://doi.org/10.1073/pnas.1106382108 Maamar Kouadri, K., Saifouni, A., Boubetra, K., & Mihoubi, A. (2024). The disparity in the germination time of argan nuts ( Argania spinosa L. Skeels) on the growth of their seedlings in nurseries. Iranian Journal of Plant Physiology, 14 (1), 4843–4850. Morton, J. F., & Voss, G. L. (1987). The argan tree ( Argania spinosa , Sapotaceae), a desert source of edible oil. Economic Botany, 41 (2), 221–233. https://doi.org/10.1007/BF02858970 Nonogaki, H., Bassel, G. W., & Bewley, J. D. (2010). Germination—Still a mystery. Plant Science, 179 (6), 574–581. https://doi.org/10.1016/j.plantsci.2010.02.010 Rana, S., et al. (2023). Pre-sowing hydration treatments improve germination in hard-coated species. Journal of Applied Research on Medicinal and Aromatic Plants, 100478. https://doi.org/10.1016/j.jarmap.2023.100478 Said Ali, O., Hachemi, A., Moumni, A., Zine, H., Elgadi, S., Belghazi, T., Ouhammou, A., Lahrouni, A., & El Messoussi, S. (2022). Argan (Argania spinosa (L.) Skeels) seed germination under some pretreatments of thermal shocks. Kastamonu University Journal of Forestry Faculty, 22(1), 56–67. https://doi.org/10.17475/kastorman.1095893 Singh, A., Kumar, R., & Sharma, P. (2023). Role of auxins in early seedling growth and biomass accumulation in woody species. Forests, 14, 1562. Taiz, L., Zeiger, E., Møller, I. M., & Murphy, A. (2015). Plant physiology and development (6th ed.). Sinauer Associates. Wang, J., Li, Q., & Zhao, L. (2022). Auxin-mediated control of plant architecture and early vegetative development. International Journal of Molecular Sciences, 23, 14567. https://doi.org/10.3390/ijms232314567 Wu, Y., Huang, W. H., Peng, C. Y., & Shen, Y. B. (2023). Effects of GA₃ and dormancy-breaking treatments in woody species. Frontiers in Plant Science, 14, 1240028. https://doi.org/10.3389/fpls.2023.1240028 Zhang, L., Wang, Q., & Sun, J. (2023). Oxygen diffusion and seed coat permeability during early germination stages. International Journal of Molecular Sciences, 24, 10217. https://doi.org/10.3390/ijms241310217 Zhang, Y., Xu, M., & He, Y. (2022). Gibberellin signaling and its role in cell elongation and meristem regulation. International Journal of Molecular Sciences, 23, 12891. https://doi.org/10.3390/ijms232012891 El Mouden, N., et al. (2023). Socioeconomic importance and value chain analysis of argan oil production systems. Sustainability, 15, 11234. Msanda, F., El Mousadik, A., & Aboudrare, A. (2022). Biodiversity conservation and ecosystem functions of the argan forest biosphere reserve. Land, 11, 1743. Zahidi, A., et al. (2024). Climate variability and adaptive performance of Argania spinosa in semi-arid environments. Resources, 13, 135. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted 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. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. 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-8933092","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":600123901,"identity":"a935b05c-b443-4934-a50d-2ff6bf9b7f66","order_by":0,"name":"Ahmed M. Eed","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAABAElEQVRIiWNgGAWjYDACCSDmATGON7Yxw9gSxGk5c5BkLTcS2JiRBXEC/tndiQ/eMNjI8d183Pa4sO2OjMEB5oO3eRgOy+G05M7ZzYZzGNKMJW8nthvPbHvGY3CALdkaqMUYpzU3crdJAxUkbrid2CbN23aYR7KBxwws0oBDh/yN3O2/eRj+12+4eRCmhf8bSEs9Li0GQFuYeRgOJBjcYIRo4WfgYQNpScDlLsMbuZsl5xgkG848A/TLjHNALcxsxpZzDNINcdkidyN344c3FXbyfMePP3tcUHbYno29+eGNNxXW8ji9D3EeMgccOwbN+HVgA3WkaxkFo2AUjILhCgDl2lU7xePebAAAAABJRU5ErkJggg==","orcid":"","institution":"Ibb University","correspondingAuthor":true,"prefix":"","firstName":"Ahmed","middleName":"M.","lastName":"Eed","suffix":""},{"id":600123902,"identity":"60143f2e-8dd1-400e-8b72-a7a99c7355e7","order_by":1,"name":"Abdullah H. Al-hajj","email":"","orcid":"","institution":"Ibb University","correspondingAuthor":false,"prefix":"","firstName":"Abdullah","middleName":"H.","lastName":"Al-hajj","suffix":""}],"badges":[],"createdAt":"2026-02-21 11:24:32","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-8933092/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-8933092/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":103935759,"identity":"6e16e609-6ff9-4cdd-a156-41992b42894b","added_by":"auto","created_at":"2026-03-04 17:39:53","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":459470,"visible":true,"origin":"","legend":"\u003cp\u003eMorphological structure of argan seeds and mechanical scarification process. a complete seed with intact hard seed coat; b mechanically scarified seeds; c intact embryos (kernels); d empty seed coats.\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-8933092/v1/a95c768b74c6eae968442d8a.png"},{"id":104438504,"identity":"0a2596ca-5207-4a50-9d91-ce71e73fa913","added_by":"auto","created_at":"2026-03-11 17:25:41","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1747953,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8933092/v1/699cf235-ef8d-443b-87eb-3ffbbde9d5c7.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Combined Effects of Mechanical Scarification, Hormonal Treatments, and Hydration Optimization on Germination and Early Seedling Growth of Argania spinosa under Plastic Tunnel Conditions","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eArgan (\u003cem\u003eArgania spinosa\u003c/em\u003e (L.) Skeels) is a multipurpose tree species native to North Africa and highly adapted to arid and semi-arid environments (El Aboudi et al., 2023; Zahidi et al., 2024). The species plays a pivotal ecological role in stabilizing fragile dryland ecosystems by reducing soil erosion, limiting desertification, and enhancing biodiversity and ecosystem resilience (Msanda et al., 2022; Aboudrare et al., 2025). Beyond its ecological importance, argan holds substantial socioeconomic value due to its high-quality oil, which is extensively utilized in the food, cosmetic, and pharmaceutical industries, making it one of the most economically significant forest tree species in dry regions (Morton \u0026amp; Voss, 1987; Lybbert et al., 2011; Charrouf \u0026amp; Guillaume, 2022; El Mouden et al., 2023).\u003c/p\u003e\n\u003cp\u003eDespite its ecological and economic relevance, large-scale propagation of argan remains constrained by poor and inconsistent natural regeneration. Low germination rates and slow seedling establishment represent major bottlenecks in nursery production systems. One of the principal constraints is seed dormancy, which in argan is predominantly physical dormancy imposed by a thick, hard, and water-impermeable seed coat that restricts imbibition, gas exchange, and embryo expansion (Bani-Aameur \u0026amp; Alouani, 1999; Alouani \u0026amp; Bani-Aameur, 2004). Physical dormancy is common among woody and desert-adapted species and typically requires disruption of the seed coat barrier to permit water uptake and initiate metabolic reactivation (Baskin \u0026amp; Baskin, 2014; Bewley et al., 2013).\u003c/p\u003e\n\u003cp\u003eIn addition to physical dormancy, evidence suggests that a physiological component may also occur in argan seeds, as improved germination has been observed following cold stratification or gibberellic acid (GA₃) application (Bani-Aameur \u0026amp; Alouani, 1999; El Qadmi et al., 2023; Maamar Kouadri et al., 2024). Physiological dormancy involves biochemical constraints within the embryo that inhibit germination even after adequate hydration (Finch-Savage \u0026amp; Leubner-Metzger, 2006). Consequently, untreated argan seeds often exhibit delayed, irregular, and low germination, resulting in prolonged nursery cycles, reduced seedling uniformity, and increased production costs (Maamar Kouadri et al., 2024).\u003c/p\u003e\n\u003cp\u003eBreaking seed dormancy through appropriate pre-sowing treatments is therefore essential for improving germination percentage, uniformity, and seedling vigor. Mechanical scarification, hot water treatment, and prolonged soaking are widely used to overcome physical dormancy in hard-coated seeds by enhancing seed coat permeability (Bewley et al., 2013). Once physical dormancy is alleviated, residual physiological constraints may require additional stimulation. Plant growth regulators (PGRs), particularly gibberellins (GA₃) and auxins such as indole-3-acetic acid (IAA) and naphthalene acetic acid (NAA), have been reported to promote germination and early seedling growth. In many woody species, a sequential approach combining mechanical scarification to break physical dormancy followed by hormonal treatments to address physiological dormancy has significantly improved germination performance (Baskin \u0026amp; Baskin, 2014). However, treatment efficacy is highly species-specific and influenced by concentration, soaking duration, and environmental conditions.\u003c/p\u003e\n\u003cp\u003eAlthough previous studies have explored dormancy-breaking methods in argan, comparative evaluations of hormonal treatments applied after physical dormancy removal, alongside simple hydration-based approaches under protected nursery conditions, remain limited. In particular, there is insufficient information regarding cost-effective and easily adoptable techniques suitable for large-scale propagation under arid and semi-arid environments similar to those of Yemen and comparable regions.\u003c/p\u003e\n\u003cp\u003eComparable improvements in germination and early seedling establishment following optimized physical and hydration-based pre-sowing treatments have been documented in several woody and horticultural species (Eed \u0026amp; Yahya, 2021; Eed \u0026amp; Al-Hajj, 2023; Eed et al., 2023). Nevertheless, the relative effectiveness of hydration versus hormonal stimulation in argan following mechanical scarification remains unclear.\u003c/p\u003e\n\u003cp\u003eAccordingly, this study was designed to systematically evaluate the effectiveness of mechanical scarification combined with hormonal and hydration treatments on germination and early seedling growth of argan under plastic tunnel conditions. By adopting a stepwise experimental approach and optimizing the most promising treatment, the study aims to identify a practical, low-cost, and scalable propagation protocol.\u003c/p\u003e\n\u003cp\u003eThe specific objectives were to:\u003c/p\u003e\n\u003col style=\"list-style-type: upper-roman;\"\u003e\n \u003cli\u003eTo evaluate the effects of different concentrations of GA₃ and selected auxins (IAA and NAA) on germination and early vegetative growth of mechanically scarified argan seeds.\u003c/li\u003e\n \u003cli\u003eTo compare hormonal treatments with hydration-based pre-sowing treatments (hot water and tap water soaking) in improving germination performance and seedling vigor under nursery conditions.\u003c/li\u003e\n \u003cli\u003eTo identify and optimize a practical propagation protocol by refining soaking duration and substrate type to maximize germination efficiency and early seedling development.\u003c/li\u003e\n\u003c/ol\u003e"},{"header":"2. Materials and Methods","content":"\u003cp\u003e\u003cstrong\u003e2.1 Research Site and Seed Source\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe study was conducted at the nurseries of the Organic Yemen Foundation, Sana'a, Yemen, through two sequential experiments designed to progressively optimize argan seed germination. The second experiment was structured based on the outcomes of the first experiment to further refine and improve germination performance.\u003c/p\u003e\n\u003cp\u003eArgan seeds were obtained from Algeria through Eng. Abdelhakim Ouzzane, Ministry of Agriculture, Algeria.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.2 Preliminary Experiments\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003ePreliminary trials were conducted to identify suitable germination procedures for argan seeds. These included: (i) sowing intact embryos on moist tissue paper for 72 h, (ii) sowing mechanically scarified seeds without further treatment, and (iii) sowing seeds with intact seed coats in a standard rooting medium under plastic tunnel conditions. None of these approaches resulted in a significant improvement in germination percentage (data not shown). Therefore, a structured experimental approach was developed to systematically address both physical and physiological dormancy constraints (Experiment I), followed by further optimization of the most promising treatment (Experiment II).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.3 Experiment I: Sequential Dormancy Removal and Growth Stimulation\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eExperiment I was conducted inside plastic tunnels at the Organic Yemen nursery in October 2021. Seeds were sown in seedling trays containing a rooting medium composed of sand, clay soil, and perlite at a 1:1:1 (v/v/v) ratio. Irrigation was applied manually every three days, or as needed, to maintain adequate moisture while preventing waterlogging and fungal contamination. This experiment was designed to sequentially remove physical dormancy through scarification, followed by evaluation of hormonal and thermal treatments aimed at overcoming possible residual physiological dormancy and stimulating early seedling growth. Germination and vegetative parameters were recorded at 30 and 60 days after sowing.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.3.1 Pre-treatment for Breaking Physical Dormancy\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eTo overcome the physical dormancy imposed by the hard, impermeable seed coat, seeds were subjected to a two-step scarification procedure. First, seeds were soaked in tap water for three days to soften the seed coat. Subsequently, mechanical scarification was carefully performed using manual tools; pliers and a hammer on a stone surface to crack the seed coat without damaging the embryo. Approximately one-third to one-half of the seed coat was removed, allowing direct exposure of the embryo prior to subsequent treatments (Fig. 1a-1d).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.3.2 Hormonal and Thermal Treatments for Overcoming Physiological Dormancy\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAfter scarification, seeds were subjected to the following treatments for 10 min to address potential physiological dormancy and stimulate germination:\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eT1:\u003c/strong\u003e GA₃ at 4000 ppm\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eT2:\u003c/strong\u003e GA₃ at 3000 ppm\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eT3:\u003c/strong\u003e GA₃ at 2000 ppm\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eT4:\u003c/strong\u003e GA₃ at 1000 ppm\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eT5:\u003c/strong\u003e NAA at 1000 ppm\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eT6:\u003c/strong\u003e IAA at 1000 ppm\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eT7:\u003c/strong\u003e Warm water (≈30°C)\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eT8:\u003c/strong\u003e Tap water (control)\u003c/p\u003e\n\u003cp\u003eThis design allowed direct comparison between hormonal stimulation, mild thermal exposure, and simple hydration following scarification.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.3.3 Measured Parameters\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe following parameters were evaluated:\u003c/p\u003e\n\u003cp\u003e2.3.3.1 Germination percentage (%)\u003c/p\u003e\n\u003cp\u003e2.3.3.2 Seedling height (cm)\u003c/p\u003e\n\u003cp\u003e2.3.3.3 Number of leaves per plant\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.3.4 Experimental Design and Statistical Analysis\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe experiment was arranged in a completely randomized design (CRD) with eight treatments. Each treatment consisted of nine seeds distributed into three replicates (three seeds per replicate).\u003c/p\u003e\n\u003cp\u003eData were subjected to analysis of variance (ANOVA) using the F-test. Treatment means were separated using Fisher’s Least Significant Difference (LSD) test at the 5% probability level. Germination percentage data were square-root transformed prior to analysis to satisfy normality assumptions. Statistical analyses were performed using OPSTAT software (CCS Haryana Agricultural University, Hisar, India).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.4 Experiment II: Optimization of Hydration Duration and Growing Substrate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eBased on the results of Experiment I, the control treatment (T8: soaking scarified seeds in tap water for 10 min) produced the highest germination percentage (33.30%). Notably, this indicated that simple hydration following scarification was more effective than exogenous hormonal application under the tested conditions.\u003c/p\u003e\n\u003cp\u003eExperiment II was therefore designed to further optimize this response by modifying soaking duration and evaluating alternative germination substrates. The experiment was conducted in February 2022.\u003c/p\u003e\n\u003cp\u003eThe following treatments were evaluated:\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eT9:\u003c/strong\u003e Soaking scarified seeds in tap water for 10 min, followed by sowing in cardboard tea pads\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eT10:\u003c/strong\u003e Soaking scarified seeds in tap water for 10 min, followed by sowing in sawdust\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eT11:\u003c/strong\u003e Soaking scarified seeds in tap water for 3 h, followed by sowing in the standard rooting medium used in Experiment I. Germination and vegetative parameters were recorded at 30 and 60 days after sowing.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.4.1 Experimental Design and Statistical Analysis\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe experiment followed a completely randomized design (CRD) identical to Experiment I. Each treatment consisted of 15 seeds arranged into three replicates (five seeds per replicate).\u003c/p\u003e\n\u003cp\u003eThe same measured parameters, data transformation procedures, and statistical analysis methods were applied.\u003c/p\u003e"},{"header":"3. Results","content":"\u003cp\u003e \u003cb\u003e3.1 Experiment I: Effects of Plant Growth Regulators and Hydration on Germination and Early Growth of Scarified Argan Seeds\u003c/b\u003e \u003c/p\u003e \u003cdiv id=\"Sec16\" class=\"Section3\"\u003e \u003cdiv class=\"Heading\"\u003e3.1.1 Germination Percentage\u003c/div\u003e \u003cp\u003eAt 30 days after sowing, germination percentage ranged from 11.10% to 33.30% across treatments (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). The highest germination (33.30%) was recorded in seeds soaked in tap water for 10 min (T8), followed by GA₃ at 1000 ppm (T4) and auxin treatments (T5 and T6), each producing 22.20%. In contrast, higher GA₃ concentrations (T1\u0026ndash;T3) and warm water treatment (T7) resulted in lower germination (11.10%). However, differences among treatments were not statistically significant.\u003c/p\u003e \u003cp\u003eA similar pattern was observed at 60 days (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e), with T8 maintaining the highest germination percentage (33.30%), while higher GA₃ concentrations and warm water treatment remained comparatively low (11.10%). Germination differences were again statistically non-significant.\u003c/p\u003e \u003cp\u003eThese results indicate that short-duration exogenous PGRs application did not enhance germination beyond simple hydration following scarification.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eEffects of PGRs and Water Treatments on Germination and Early Seedling Growth of Mechanically Scarified Argan Seeds 30 Days after Sowing under Plastic Tunnel Conditions\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTreatments\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eGermination %*\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePlant Height (cm)*\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eNo of leaves/plant*\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eT1: Soaking cracked seeds in a GA₃ @ 4000 ppm for 10 min\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e11.10\u003c/p\u003e \u003cp\u003e(2.61)\u003csup\u003eNS\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e6.66\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e8.33\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eT2: Soaking cracked seeds in a GA₃ @ 3000 ppm for 10 min\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e11.10 (2.61)\u003csup\u003eNS\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4.66\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e11.66\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eT3: Soaking cracked seeds in a GA₃ @ 2000 ppm for 10 min\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e11.10 (2.61)\u003csup\u003eNS\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.00\u003csup\u003ed\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3.33\u003csup\u003ede\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eT4: Soaking cracked seeds in a GA₃ @ 1000 ppm for 10 min\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e22.20 (4.23)\u003csup\u003eNS\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.20\u003csup\u003ed\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2.33\u003csup\u003ede\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eT5: Soaking cracked seeds in an NAA @ 1000 ppm for 10 min\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e22.20 (3.40)\u003csup\u003eNS\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.33\u003csup\u003ed\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e4.66\u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eT6: Soaking cracked seeds in an IAA @ 1000 ppm for 10 min\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e22.20\u003c/p\u003e \u003cp\u003e(4.23)\u003csup\u003eNS\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.00\u003csup\u003ed\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2.00\u003csup\u003ee\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eT7: Soaking cracked seeds in hot water for 10 min\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e11.10 (2.61)\u003csup\u003eNS\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.83\u003csup\u003ecd\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2.00\u003csup\u003ee\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eT8: Soaking cracked seeds in tap water for 10 min\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e33.30 (5.85)\u003csup\u003eNS\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.33\u003csup\u003ed\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2.33\u003csup\u003ede\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"4\" nameend=\"c4\" namest=\"c1\"\u003e \u003cp\u003e* Within columns, mean values followed by different superscript letters differ significantly (p\u0026thinsp;\u0026lt;\u0026thinsp;0.05) as determined by Fisher\u0026rsquo;s least significant difference (LSD) test.\u003c/p\u003e \u003cp\u003eValues in parentheses are square-root transformed.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec17\" class=\"Section3\"\u003e \u003cdiv class=\"Heading\"\u003e3.1.2 Plant Height\u003c/div\u003e \u003cp\u003eSignificant differences in seedling height were observed at both evaluation periods. At 30 days, GA₃ at 4000 ppm produced the tallest seedlings (6.66 cm), followed by GA₃ at 3000 ppm (4.66 cm), whereas other treatments resulted in comparatively shorter seedlings (2.00\u0026ndash;2.83 cm) (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). At 60 days, the same trend persisted, with GA₃ at 4000 ppm and 3000 ppm producing the greatest plant heights (8.66 and 6.66 cm, respectively) (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). Seedlings from other treatments generally remained below 4 cm.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eEffects of Plant Growth Regulator and Water Treatments on Germination and Early Seedling Growth of Mechanically Scarified Argan Seeds 60 Days after Sowing under Plastic Tunnel Conditions\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTreatments\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eGermination %*\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePlant Height (cm)*\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eNo of leaves/plant*\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eT1: Soaking cracked seeds in a GA₃ @ 4000 ppm for 10 min\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e11.10 (2.61)\u003csup\u003eNS\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e8.66\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e11.33\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eT2: Soaking cracked seeds in a GA₃ @ 3000 ppm for 10 min\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e11.10 (2.61)\u003csup\u003eNS\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e6.66\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e14.66\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eT3: Soaking cracked seeds in a GA₃ @ 2000 ppm for 10 min\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e11.10 (2.61)\u003csup\u003eNS\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.66\u003csup\u003ed\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e4.33\u003csup\u003ed\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eT4: Soaking cracked seeds in a GA₃ @ 1000 ppm for 10 min\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e22.20 (4.23)\u003csup\u003eNS\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.83\u003csup\u003ed\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3.33\u003csup\u003ee\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eT5: Soaking cracked seeds in an NAA @ 1000 ppm for 10 min\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e22.20 (4.23)\u003csup\u003eNS\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3.33\u003csup\u003ecd\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e4.66\u003csup\u003ecd\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eT6: Soaking cracked seeds in an IAA @ 1000 ppm for 10 min\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e22.20 (4.23)\u003csup\u003eNS\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3.16\u003csup\u003ecd\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2.33\u003csup\u003ef\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eT7: Soaking cracked seeds in hot water for 10 min\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e11.10 (2.61)\u003csup\u003eNS\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3.83\u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2.00\u003csup\u003ef\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eT8: Soaking cracked seeds in tap water for 10 min\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e33.30 (2.85)\u003csup\u003eNS\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.66\u003csup\u003ed\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2.66\u003csup\u003eef\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"4\" nameend=\"c4\" namest=\"c1\"\u003e \u003cp\u003e* Within columns, mean values followed by different superscript letters differ significantly (p\u0026thinsp;\u0026lt;\u0026thinsp;0.05) as determined by Fisher\u0026rsquo;s least significant difference (LSD) test.\u003c/p\u003e \u003cp\u003eValues in parentheses are square-root transformed.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec18\" class=\"Section3\"\u003e \u003cdiv class=\"Heading\"\u003e3.1.3 Number of Leaves per Plant\u003c/div\u003e \u003cp\u003eLeaf production differed significantly among treatments at both observation periods. At 30 days, GA₃ at 3000 ppm produced the highest leaf number (11.66 leaves plant⁻\u0026sup1;), followed by GA₃ at 4000 ppm (8.33 leaves plant⁻\u0026sup1;), while warm water and IAA treatments recorded the lowest values (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). At 60 days, GA₃ at 3000 ppm again resulted in the highest leaf number (14.66 leaves plant⁻\u0026sup1;), followed by GA₃ at 4000 ppm (11.33 leaves plant⁻\u0026sup1;) (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). Hydration-only and auxin treatments produced comparatively fewer leaves. Overall, while GA₃ significantly enhanced vegetative growth, it did not improve germination percentage relative to simple tap water soaking.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec19\" class=\"Section2\"\u003e \u003ch2\u003e3.2 Experiment II: Optimization of Hydration Duration and Germination Substrate\u003c/h2\u003e \u003cp\u003eResults from Experiment I demonstrated that simple hydration after scarification (T8) produced the highest germination percentage, whereas PGR treatments did not confer additional benefits. Therefore, Experiment II focused on optimizing hydration duration and evaluating alternative germination substrates to further improve emergence and seedling establishment.\u003c/p\u003e \u003cdiv id=\"Sec20\" class=\"Section3\"\u003e \u003ch2\u003e3.2.1 Germination Percentage\u003c/h2\u003e \u003cp\u003eMarked and statistically significant differences were observed among treatments (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). At 30 days after sowing, soaking scarified seeds in tap water for 3 h (T11) resulted in 100% germination, significantly exceeding all other treatments. Soaking for 10 min followed by sowing in cardboard tea pads (T9) achieved 73.30% germination, whereas sowing in sawdust (T10) resulted in only 13.30%. The same pattern was maintained at 60 days (Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e), with T11 sustaining 100% germination, followed by T9 (73.30%), while T10 remained significantly lower (13.30%). This represents a threefold increase compared with the best treatment in Experiment I.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eEffect of Water Treatments on Germination and Early Seedling Growth of Mechanically Scarified Argan Seeds 30 Days after Sowing under Plastic Tunnel Conditions\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTreatments\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eGermination %*\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePlant Height (cm)*\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eNo of leaves/plant*\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eT9: Soaking scarified seeds in tap water for 10 min, followed by planting in cardboard tea pads\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e73.30 (8.60)\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.60\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2.66\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eT10: Soaking scarified seeds in tap water for 10 min, followed by planting in sawdust.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e13.30 (3.73)\u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.43\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.00\u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eT11: Soaking scarified seeds in tap water for 3 hr\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e100\u003c/p\u003e \u003cp\u003e(10.05)\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.16\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1.48\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"4\" nameend=\"c4\" namest=\"c1\"\u003e \u003cp\u003e* Within columns, mean values followed by different superscript letters differ significantly (p\u0026thinsp;\u0026lt;\u0026thinsp;0.05) as determined by Fisher\u0026rsquo;s least significant difference (LSD) test.\u003c/p\u003e \u003cp\u003eValues in parentheses are square-root transformed.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec21\" class=\"Section3\"\u003e \u003ch2\u003e3.2.2 Plant Height\u003c/h2\u003e \u003cp\u003eSignificant differences in seedling height were observed among treatments. At 30 days, T9 produced the tallest seedlings (2.60 cm), followed by T11 (1.16 cm), while T10 resulted in minimal growth (0.43 cm) (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). By 60 days, T11 produced the greatest plant height (7.14 cm), followed by T9 (4.38 cm), whereas T10 remained significantly inferior (0.66 cm) (Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eEffect of Water Treatments on Germination and Early Seedling Growth of Mechanically Scarified Argan Seeds 60 Days after Sowing under Plastic Tunnel Conditions\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTreatments\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eGermination %*\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePlant Height (cm)*\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eNo of leaves/plant*\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eT9: Soaking scarified seeds in tap water for 10 min, followed by planting in cardboard tea pads\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e73.30\u003c/p\u003e \u003cp\u003e(8.55)\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4.38\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e8.66\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eT10: Soaking scarified seeds in tap water for 10 min, followed by planting in sawdust.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e13.30\u003c/p\u003e \u003cp\u003e(3.38)\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.66\u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2.00\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eT11: Soaking scarified seeds in tap water for 3 hr\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e100.00\u003c/p\u003e \u003cp\u003e(10.05)\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e7.14\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e11.96\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"4\" nameend=\"c4\" namest=\"c1\"\u003e \u003cp\u003e* Within columns, mean values followed by different superscript letters differ significantly (p\u0026thinsp;\u0026lt;\u0026thinsp;0.05) as determined by Fisher\u0026rsquo;s least significant difference (LSD) test.\u003c/p\u003e \u003cp\u003eValues in parentheses are square-root transformed.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec22\" class=\"Section3\"\u003e \u003ch2\u003e3.2.3 Number of Leaves per Plant\u003c/h2\u003e \u003cp\u003eLeaf production followed a trend similar to plant height. At 30 days, T9 produced the highest leaf number (2.66 leaves plant⁻\u0026sup1;), followed by T11 (1.48 leaves plant⁻\u0026sup1;), while no leaf development was observed under T10 (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). At 60 days, both T11 and T9 significantly enhanced leaf production (11.96 and 8.66 leaves plant⁻\u0026sup1;, respectively), compared with only 2.00 leaves under T10 (Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e).\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e"},{"header":"4. Discussion","content":"\u003cp\u003eSuccessful domestication and large-scale propagation of \u003cem\u003eArgania spinosa\u003c/em\u003e (L.) Skeels remain constrained by low and inconsistent seed germination, largely attributed to strong physical dormancy imposed by the hard seed coat (Baskin \u0026amp; Baskin, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e2014\u003c/span\u003e; El Aboudi et al., 2017). Physical dormancy in woody species typically restricts water uptake and gas exchange, thereby delaying embryo activation (Baskin \u0026amp; Baskin, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e2014\u003c/span\u003e; Bewley et al., \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e2013\u003c/span\u003e). In the present study, a stepwise experimental strategy was adopted to systematically identify and optimize effective dormancy-breaking treatments under plastic tunnel conditions. Preliminary trials (data not shown) indicated poor germination under conventional sowing approaches, which justified the implementation of mechanical scarification followed by hormonal and hydration treatments (Experiment I). Based on these outcomes, Experiment II refined the most promising treatment by optimizing soaking duration and substrate type. This progressive design allowed the development of a highly efficient, low-cost propagation protocol. Importantly, the findings demonstrate that once physical dormancy is disrupted, hydration\u0026mdash;rather than hormonal stimulation\u0026mdash;is the principal determinant of germination success in argan.\u003c/p\u003e \u003cdiv id=\"Sec24\" class=\"Section2\"\u003e \u003ch2\u003e4.1 Plant Growth Regulator Effects on Germination of Scarified Argan Seeds\u003c/h2\u003e \u003cp\u003eIn Experiment I, germination percentage remained statistically non-significant among most treatments, including all concentrations of GA₃, NAA, and IAA. These results suggest that exogenous hormonal application following scarification does not substantially enhance germination beyond hydration alone (Jatana et al., \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e2024\u003c/span\u003e; Wu et al., \u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e2023\u003c/span\u003e). Gibberellic acid (GA₃) is well known to stimulate germination in seeds exhibiting physiological dormancy by promoting α-amylase production, endosperm weakening, and embryo elongation (Bewley et al., \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e2013\u003c/span\u003e; Taiz et al., \u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e2015\u003c/span\u003e; Liu et al., \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e2022\u003c/span\u003e; Chang et al., \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e2024\u003c/span\u003e). However, its limited effect in this study indicates that argan seeds likely lack a strong physiological dormancy component once the mechanical barrier is removed.\u003c/p\u003e \u003cp\u003eSimilar observations have been reported in hard-coated woody species where GA₃ improved germination only when physiological constraints were present, but showed limited effect when dormancy was primarily physical (Baskin \u0026amp; Baskin, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e2014\u003c/span\u003e; Hartmann et al., \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e2018\u003c/span\u003e; Rana et al., \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; El Qadmi et al., \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e2023\u003c/span\u003e). Therefore, our results reinforce that seed coat impermeability is the dominant dormancy mechanism in argan.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec25\" class=\"Section2\"\u003e \u003ch2\u003e4.2 Growth-promoting effects of GA₃ and auxins\u003c/h2\u003e \u003cp\u003eAlthough hormonal treatments did not significantly increase germination percentage, GA₃ at higher concentrations (3000\u0026ndash;4000 ppm) significantly enhanced plant height and leaf number (Liu et al., \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e2022\u003c/span\u003e; Jatana et al., \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e2024\u003c/span\u003e). Gibberellins are widely documented to promote stem elongation, cell division, and leaf expansion through stimulation of cell wall extensibility and meristem activity (Davies, \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e2010\u003c/span\u003e; Taiz et al., \u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e2015\u003c/span\u003e; Zhang et al., \u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e2022\u003c/span\u003e; Chen et al., \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2023\u003c/span\u003e). Similarly, auxins (IAA and NAA) slightly improved early vegetative growth (Singh et al., \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Wang et al., \u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). Auxins regulate cell elongation, vascular differentiation, and apical dominance, thereby enhancing early seedling vigor (Davies, \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e2010\u003c/span\u003e; Li et al., \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e2023\u003c/span\u003e). These findings indicate that plant growth regulators may be beneficial for post-germination growth enhancement, even though they are not essential for dormancy release in argan. This distinction between germination control and vegetative growth promotion has practical implications for nursery management (Jatana et al., \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e2024\u003c/span\u003e).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec26\" class=\"Section2\"\u003e \u003ch2\u003e4.3 Superiority of water soaking for promoting germination\u003c/h2\u003e \u003cp\u003eA key finding of Experiment I was that soaking scarified seeds in tap water for 10 minutes consistently produced the highest germination percentage. Notably, this simple hydration treatment outperformed both hormonal applications and hot water soaking (Rana et al., \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Jatana et al., \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e2024\u003c/span\u003e). Water uptake (imbibition) is the first critical step in germination and initiates metabolic reactivation, mitochondrial repair, enzyme synthesis, and radicle protrusion (Bewley et al., \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e2013\u003c/span\u003e; Liu et al., \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e2022\u003c/span\u003e; Chen et al., \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2023\u003c/span\u003e). Enhanced hydration improves oxygen diffusion and softens residual seed coat tissues, facilitating embryo expansion (Finch-Savage \u0026amp; Leubner-Metzger, \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e2006\u003c/span\u003e; Zhang et al., \u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e2023\u003c/span\u003e). In contrast, excessive thermal exposure may damage embryo tissues or induce secondary stress responses, particularly in species not adapted to fire-related dormancy release (Baskin \u0026amp; Baskin, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e2014\u003c/span\u003e). Similar results have been documented in other hard-seeded tree species, where moderate hydration treatments proved safer and more effective than chemical or thermal scarification (Baskin \u0026amp; Baskin, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e2014\u003c/span\u003e; Hartmann et al., \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e2018\u003c/span\u003e; Rana et al., \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; El Qadmi et al., \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e2023\u003c/span\u003e). Thus, the present study demonstrates that hydration is the primary activating factor once mechanical resistance is reduced. Thus, the present study demonstrates that hydration is the primary activating factor once mechanical resistance is reduced.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec27\" class=\"Section2\"\u003e \u003ch2\u003e4.4 Optimization through soaking duration and substrate modification\u003c/h2\u003e \u003cp\u003eBecause short-duration soaking yielded promising results, Experiment II investigated prolonged soaking and substrate effects. Extending soaking duration to 3 hours resulted in 100% germination (Jatana et al., \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e2024\u003c/span\u003e; Rana et al., \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e2023\u003c/span\u003e). Extended soaking likely enables complete water penetration through partially scarified tissues, accelerating metabolic activation, enzyme synthesis, and uniform radicle emergence (Finch-Savage \u0026amp; Leubner-Metzger, \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e2006\u003c/span\u003e; Bewley et al., \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e2013\u003c/span\u003e; Liu et al., \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e2022\u003c/span\u003e; Chen et al., \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2023\u003c/span\u003e). Improved germination rate and uniformity following optimized hydration periods have been widely reported in woody and desert-adapted species (Hartmann et al., \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e2018\u003c/span\u003e; El Qadmi et al., \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e2023\u003c/span\u003e). Substrate type significantly influenced outcomes. Cardboard tea pads promoted higher germination and seedling growth compared with sawdust. Successful germination requires an optimal water\u0026ndash;air balance in the rooting medium (Landis et al., \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e2014\u003c/span\u003e; Abad et al., \u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e2023\u003c/span\u003e). Excessively compact or nutrient-immobilizing substrates, such as undecomposed sawdust, may restrict oxygen diffusion and nutrient availability (Landis et al., \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e2014\u003c/span\u003e; Kumar et al., \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). The integration of optimized hydration duration with an appropriate substrate represents a practical refinement that maximizes germination efficiency.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec28\" class=\"Section2\"\u003e \u003ch2\u003e4.5 Implications and novelty for argan propagation\u003c/h2\u003e \u003cp\u003eThe present study establishes a clear and operational propagation protocol for \u003cem\u003eArgania spinosa\u003c/em\u003e under protected nursery conditions. Once physical dormancy was eliminated through mechanical scarification, prolonged hydration in tap water proved sufficient to achieve near-complete germination (100%) without the need for exogenous plant growth regulators. The principal novelty of this work lies in demonstrating that optimization of hydration following scarification, rather than hormonal supplementation, is the critical determinant of successful germination. While previous studies have emphasized gibberellic acid or chemical treatments to enhance germination, the present findings clarify that such inputs are not essential once the mechanical barrier imposed by the seed coat is removed.\u003c/p\u003e \u003cp\u003eThis provides both physiological insight\u0026mdash;confirming that dormancy in argan is primarily physical\u0026mdash;and a directly applicable, low-cost nursery technique. From a practical standpoint, the proposed protocol is economically feasible, environmentally sustainable, and easily transferable to large-scale propagation systems in arid and semi-arid regions, thereby supporting domestication, conservation, and reforestation programs.\u003c/p\u003e \u003c/div\u003e"},{"header":"5. Conclusion","content":"\u003cp\u003e\u003cstrong\u003e5.1\u0026nbsp;\u003c/strong\u003eThis study confirms that dormancy in \u003cem\u003eArgania spinosa\u003c/em\u003e seeds is primarily physical and imposed by the hard seed coat. Mechanical scarification effectively removes this constraint, and adequate hydration is the key factor controlling successful germination.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e5.2\u0026nbsp;\u003c/strong\u003eProlonged soaking of scarified seeds in tap water for three hours resulted in 100% germination, whereas exogenous plant growth regulators did not significantly enhance germination percentage, although gibberellic acid promoted subsequent vegetative growth.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e5.3\u0026nbsp;\u003c/strong\u003eThe optimized protocol\u0026mdash;mechanical scarification followed by controlled hydration and appropriate substrate selection\u0026mdash;provides a simple, economical, and scalable method for argan nursery production and restoration initiatives in arid environments.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable. This study did not involve human participants or vertebrate animals.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis research received no specific grant from funding agencies in the public, commercial, or not-for-profit sectors.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no competing interests.\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eAME designed the study, conducted Experiment I, performed data analysis, and wrote the main manuscript text. AHA conducted Experiment II and contributed to data collection and interpretation. Both authors reviewed and approved the final manuscript.\u003c/p\u003e\u003ch2\u003eData Availability\u003c/h2\u003e\u003cp\u003eThe datasets generated and/or analyzed during the current study are available from the corresponding author, Ahmed M. Eed, on reasonable request.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eAbad, M., Noguera, P., \u0026amp; Bures, S. (2023). Growing media properties and their influence on seed germination and seedling development. Horticulturae, 9, 642. https://doi.org/10.3390/horticulturae9060642 \u003c/li\u003e\n\u003cli\u003eAboudrare, A., El Mousadik, A., \u0026amp; Msanda, F. (2025). Ecological services and climate resilience of Argania spinosa in semi-arid ecosystems. Plants, 14, Article 664.\u003c/li\u003e\n\u003cli\u003eAlouani, M., \u0026amp; Bani-Aameur, F. (2004). 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Resources, 13, 135. \u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"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":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Argania spinosa, seed dormancy, mechanical scarification, hydration optimization, gibberellic acid, germination percentage","lastPublishedDoi":"10.21203/rs.3.rs-8933092/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8933092/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e \u003cem\u003eArgania spinosa\u003c/em\u003e (L.) is an ecologically and economically important tree species native to North Africa; however, its large-scale propagation is constrained by low and irregular germination due primarily to strong physical dormancy imposed by a hard, impermeable seed coat. This study aimed to systematically evaluate and optimize dormancy-breaking treatments to enhance germination and early seedling growth under plastic tunnel conditions. Two successive experiments were conducted using mechanically scarified seeds to eliminate physical dormancy. In Experiment I, scarified seeds were soaked for a fixed duration in different plant growth regulators (PGRs) including gibberellic acid (GA₃), naphthalene acetic acid (NAA), and indole-3-acetic acid (IAA), alongside hot water and tap water treatments. Based on the most promising treatment, Experiment II further optimized soaking duration and germination substrate. Germination percentage, plant height, and leaf number were assessed at 30 and 60 days after sowing. The results indicate that, in Experiment I, PGRs did not significantly improve germination compared with simple tap water soaking, which achieved the highest germination percentage (33.30%). However, higher concentrations of GA\u003csub\u003e3\u003c/sub\u003e significantly enhanced vegetative growth. In Experiment II, extending soaking duration from 10 minutes to 3 hours dramatically increased germination to 100% and significantly improved seedling development. Substrate type also affected emergence, with cardboard-based media achieving 73.30% germination compared to 13.30% in sawdust. These indicate that prolonged hydration following mechanical scarification is more effective for maximizing germination than short-duration hormonal treatments. The optimized protocol including mechanical scarification followed by prolonged soaking in tap water and sowing in a well-aerated substrate, offers a simple, low-cost, and scalable strategy for argan nursery production and restoration programs in arid and semi-arid regions.\u003c/p\u003e","manuscriptTitle":"Combined Effects of Mechanical Scarification, Hormonal Treatments, and Hydration Optimization on Germination and Early Seedling Growth of Argania spinosa under Plastic Tunnel Conditions","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-03-04 17:39:36","doi":"10.21203/rs.3.rs-8933092/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"74258528-036c-4314-a7a2-ed2046909527","owner":[],"postedDate":"March 4th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2026-03-11T17:25:19+00:00","versionOfRecord":[],"versionCreatedAt":"2026-03-04 17:39:36","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8933092","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8933092","identity":"rs-8933092","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}