Effects of increased precipitation and on the life history of spring- and autumn-germinated plants of the annual Hypecoum erectum L.

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Shanlin Yang, Rongrong Cui, Xueying Yang, Yuting Hu, Yan Ji, Renjie Li, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8417446/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 Precipitation change is one of the research hotspots in global climate change nowadays and a major environmental factor affecting plant growth and development. In this study, we mainly analyzed the life-history traits of spring-and autumn-germinated seeds of H. erectum L. By conducting a field control experiment with three precipitation regimes (natural precipitation, 30% water addition, and 50% water addition), we comparatively investigated the phenology, seedling survival rate, plant size, seed yield, and biomass accumulation and allocation of SG and AG plants. The results showed that increased precipitation delayed the phenology of both SG and AG plants, and significantly improved seedling survival rate, with the survival rate of AG plants being remarkably lower than that of SG conspecifics. In addition, increased precipitation significantly increased the leaf number, branch number, branch length and plant height of SG plants, whereas it remarkably decreased the leaf number and root length of AG plants. After water addition, the seed production of both SG and AG plants increased significantly, with the seed yield of AG plants being remarkably higher than that of SG ones. With the increase in precipitation, the proportion of dormant seeds of SG plants increased significantly, whereas the corresponding proportion of AG plants decreased remarkably. The effects of increased precipitation on the life history of H. erectum L. varied with germination seasons, which is of great significance for predicting its population dynamics under climate change. Climate change Ephemeral plant life histery Hypecoum erectum L. Increased precipictation Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 1. Introduction With global climate warming, changes in precipitation characteristics represent one of the most critical aspects of global climate change, exerting negative and potential impacts on global terrestrial ecosystems and biodiversity[9]. Plants are key components of terrestrial ecosystems, and precipitation change directly regulates plant growth and reproduction[22]. The impact of increased/decreased precipitation during the growing season on plant growth is one of the critical issues in ecological research[25]. As a core environmental factor regulating plant growth and development, the spatiotemporal variation of precipitation profoundly shapes plant life-history strategies[5]. As a key environmental factor for plant germination and growth, precipitation exerts profound impacts on plant physiological and ecological processes, dry matter accumulation and allocation, as well as the structure and function of ecosystems[24]. Increased precipitation not only promotes seedling germination but also exhibits a significantly positive correlation with plant growth[21]. During the plant vegetative growth stage, increased precipitation can accelerate the growth of new leaves and branches in ephemeral plants, and significantly affect the phenological characteristics, biomass accumulation and allocation of dominant ephemeral plant species, as well as plant diversity[27]. Furthermore, the maternal plant environment can also induce changes in seed germination potential and germination rate[4]. Seeds produced in wet seasons often are more dormant than those produced in dry warm years[3]. Therefore, against the backdrop of altered precipitation patterns, investigating the mechanisms underlying plant biomass accumulation and allocation as well as seed responses to precipitation changes is of great significance. In arid and semi-arid regions, water is the primary limiting factor for plant growth and development, while precipitation (including snowmelt) serves as the main source of water[10]. As a unique plant group in this region, ephemeral plants can germinate utilizing winter snowmelt and early spring precipitation, grow rapidly, efficiently capture light, allocate a high proportion of biomass to seeds[26], and complete their life cycle before the onset of summer, thus being highly sensitive to changes in precipitation amount. Seed germination marks the initiation of the life cycle of annual plants, and germination timing is a specific indicator of seed germination behavior. Variations in germination timing exert significant impacts on plant growth, life-history traits, competitive ability, and reproductive output[1]. Some annual plants exhibit two germination seasons: autumn and spring, and germination timing is a consequence of long-term adaptation to environmental conditions[7]. When autumn precipitation is sufficient, seeds germinate and overwinter as rosettes, completing their life cycle in the following spring[8]. When autumn precipitation decreases, seeds remain dormant until the following spring, when snowmelt moistens the soil, and then rapidly complete their life cycle. Significant differences exist in phenology, survival rate, morphological characteristics, dry matter accumulation and allocation, as well as seed dormancy traits between spring- and autumn-germinated plants of the same species. The “bet-hedging” germination strategy of SG and AG plants reflects the plants' response and adaptation strategies to environmental conditions in different seasons. Hypecoum erectum L. is a common ephemeral plant native to the Changbai Mountain region of China, characterized by SG and AG habits and biannual flowering, and is mainly distributed in Russia, Mongolia, and China. It is widely distributed in the Changbai Mountains region of Jilin Province in China, with its vegetation coverage reaching 10%-12% in this area in May[23]. SG plants initiate growth when temperatures rise in spring, utilizing sufficient water and light during this season for rapid growth and reproduction. AG plants germinate in autumn and grow by utilizing the relatively mild climate and sufficient light during this season[12]. Ephemeral plants are more sensitive to nitrogen deposition than perennial plants. Therefore, based on the differences in the life cycles of SG and AG plants, we hypothesize that the life-history traits of SG H. erectum are more sensitive to precipitation than those of AG individuals. To test this hypothesis, we conducted a comparative analysis of the phenology, survival rate, morphological characteristics, and biomass accumulation and allocation between SG and AG plants of H. erectum in the Changbai Mountain region. In addition, we conducted germination experiments on seeds collected under all experimental conditions to determine the effects of maternal plant environment on seed dormancy and dormancy ratio. 2. Materials and methods 2.1 Seed germination of study species Freshly harvested seeds of H. erectum germinate at a rate of 25% under the condition of 25/10℃, and the non-germinated seeds are water-impermeable, thus exhibiting physical dormancy. Freshly harvested seeds buried in the original habitat had a germination rate of 20% from July to early November, with an additional 5% germinating by March of the following year. This is because 25% of the seeds buried in the soil are water-permeable, therefore, we speculate that the soil moisture in autumn is insufficient to trigger germination of all water-permeable seeds, while the remaining 5% of water-permeable seeds require increased soil moisture in late winter to germinate. 2.2 Study site The Changbai Mountains represent the highest mountain range in Northeast Asia, and the study area is located on the northern slope of the Changbai Mountains (127°40′-128°16′ E, 41°35′-42°25′N) (Fig. 1 A-C). This region holds extremely important status in terms of geography, ecology, and hydrology, featuring a typical temperate continental mountain climate. The annual average temperature ranges from 3 ℃ to 7 ℃, decreasing continuously with increasing altitude, while the annual average precipitation is 600–1400 mm (Fig. 1 D) and the annual evaporation is 500–800 mm. During the growing season, the average soil volumetric water content ranges from 40% to 60% (Fig. 1 E). The region is covered by snow in winter, with a stable snow cover period of up to 6 months and an average snow depth of 30–50 cm. Winter snowfall accounts for approximately 10% of the annual precipitation. Snowmelt in early spring provides favorable moisture conditions for the growth and development of ephemeral plants in the short spring season. 2.3 Experimental procedure The experimental materials used in this study were mature seeds of H. erectum samples were collected from the Changbai Mountain Experimental Area in northeastern China in June 2024 and June 2025. The sampling site is a non-nature reserve area, where H. erectum is a common wild herbaceous plant and is not listed in the national or local List of Key Protected Wild Plants. In accordance with the relevant provisions of the Regulations of the People's Republic of China on the Protection of Wild Plants, no special collection permit was required for this sampling. The experimental seeds were identified by Professor Wu Shixiong from Changchun University. All seeds were collected from maternal plants, ensuring accurate species classification. The corresponding voucher specimens of the plants (Accession No.: CCU-WSX-2023-63) are currently deposited in the Herbarium of the College of Landscape Architecture, Changchun University. To simulate the precipitation in the Changbai Mountain region under current, future, and extreme scenarios, we conducted precipitation treatments on seeds of SG and AG plants based on the actual spring and summer precipitation in the study area in 2023. The treatments included 0% increase in precipitation (SG 0 , AG 0 ), 30% increase in precipitation (SG 30 , AG 30) , and 50% increase in precipitation (SG 50 , AG 50 ) (Fig. 2 A). 6 treatment groups were established in the experiment, with 12 plots (1 m × 1 m) per group (5 plots for phenological observation, 6 plots for trait determination and biomass sampling, and 1 plot as a reserve). To reduce inter-treatment interference, each treatment was spaced 2 m apart, and a 0.5 m deep impermeable layer (plastic sheet) was buried 1 m away between adjacent plots (Fig. 2 B). The plots were distributed in relatively uniform and flat inter-dunal lowlands. In addition, to prevent competition from other plants, manual weeding was conducted in the plots in November 2024 and early April 2025 after snowmelt. All plots were surrounded by black plastic film, which was buried 50 cm deep into the soil and protruded 10 cm above the ground to avoid runoff of irrigation water into non-irrigated areas. Based on the daily precipitation data from climate and soil moisture monitoring devices, the treatments with 30% and 50% increases in precipitation were implemented on the 2 d after each precipitation event. 2.4 Measurements and sampling 2.4.1 Phenology Following the phenological recording method described by Lu et al. (2014)[ 16 ], during the growing season of SG and AG H. erectum plants, observations were conducted and recorded in the 5 phenological observation plots of each treatment throughout the entire life cycle from seed germination to plant withering. The recorded phenological traits included emergence date (i.e., the number of days until all seeds in each plot had emerged), leafing date (the number of days until all plants in each plot had four leaves), first flowering date (the number of days until 25% of the plants in each plot had flowered), peak flowering date (the number of days until 50% of the plants in each plot had flowered), last flowering date (the number of days until 95% of the plants in each plot had flowered), fruiting date (the number of days until the first fruit on all plants in each plot turned brown), and withering date (the number of days until all plants in each plot had withered). Additionally, flowering duration (the number of days from the first flowering date to the last flowering date) and life cycle (the number of days from the emergence date to the withering date) were calculated. 2.4.2 Survivorship During the SG and AG seasons of H. erectum , the number of surviving plants in the corresponding plots was monitored regularly across the 6 treatment groups. The monitoring interval was set at 7 d, continuing until the end of the fruit harvesting period. 2.4.3 Morphological characters At plant maturity, measurements were conducted across 36 quadrats subjected to 6 different treatments (with 6 quadrats per treatment). Plant height, taproot length, and branch length were measured using a vernier caliper (Mitutoyo-500-196-30). Leaf area was quantified with a portable leaf area meter (LI-3000C). Additionally, the number of leaves, the number of branches, and the number of ramifications were recorded. 2.4.4 Dry mass accumulation and allocation H. erectum plants in 36 plots across 6 treatment groups (including both SG and AG plants) were selected as the research objects. Sample collection strictly followed the ripeness standard of pods turning yellow but not dehiscing, and the whole-plant harvesting date was determined according to the fruit maturation time. When excavating, intact root systems were obtained by taking soil cores centered on each plant with a radius of 20 cm and a depth of 50 cm (fully considering the root length of 30–40 cm). In the laboratory, plants were separated into four components: roots, stems, leaves, and fruits. After oven-drying at 80℃ for 48 h, each component was weighed using a Sartorius BS210S electronic balance (0.0001 g precision). Total biomass was calculated as the sum of roots, stems, leaves, and reproductive organs (flowers, fruits, and seeds). The biomass allocation of roots, stems, leaves, and fruits was expressed as percentages. 2.4.5 Offspring seed germination Mature seeds of SG and AG H. erectum plants were collected from different treatments on June 15, 2025, as materials for the germination experiment. The germination experiment started on June 20, 2025, with 4 replicates per treatment and 30 seeds per replicate. Seeds were evenly sown in 90 mm Petri dishes lined with 2 layers of moist filter paper (moistened with 3 mL of distilled water) and incubated under conditions of 25/15℃ and a 12/12 h light/dark cycle. During the 30 d experiment, germinated seeds (marked by a radicle protruding 2 mm) were recorded and removed daily, with distilled water supplemented to compensate for evaporation loss. The final germination percentage (FPG) was calculated using the formula: FPG = GN / SN (GN: total number of germinated seeds; SN: number of viable seeds). All non-germinated seeds were tested for viability by staining with 0.5% TTC solution at 25℃ for 24 h, and seeds with embryos stained red or pink were deemed viable. 2.5 Statistical analysis One-way analysis of variance (One-way ANOVA) was used to analyze the effects of year, nitrogen addition, and nitrogen-water interaction on plant survival rate, morphological traits, biomass, and seed germination characteristics. Based on the results of multi-factor analysis of variance (ANOVA), the Tukey's test was used for multiple comparisons of growth and biomass variables with significant differences to identify significant differences among different treatments. All data analyses were performed using SPSS 24.0 software, and graphs were plotted with Origin 2018 software (Origin Lab, Northampton, MA, USA). 3. Results 3.1 Precipitation and temperature During the observation period, the daily average temperature gradually decreased from October 2024, reached the minimum (-20℃) on January 9, 2025, and rapidly rose to 26℃ on July 9, 2025 (Fig. 1 D). The snowmelt process began on March 10, 2025. As the snow cover started to melt, soil moisture increased and remained above 40% from mid-March onward (Fig. 1 E). 3.2 Phenology Under natural precipitation conditions, the phenological phases of AG plants were earlier than those of SG plants, while their life cycle was longer. After increasing precipitation, both SG and AG plants showed phenological delays. The first flowering date was extended by 1 d, and the last flowering date was prolonged by 1–3 d (Table 1 ). Table 1 Effects of increased nitrogen, and precipitation plus nitrogen treatments on phenology of SG and AG plants of H. erectum Phenology Emergence date (month-day) Leafing date (month-day) First flowering date (month-day) Flowering duration (d) Peak flowering date (month-day) Last flowering date (month-day) Fruiting date (month-day) Withering date (month-day) Life cycle (d) SG 0 AG 0 SG 30 AG 30 SG 50 AG 50 3–30 ~ 4–5 4–6 ~ 5–12 5–8 20 5–15 5–27 5–23 ~ 6–10 6−2 ~ 6–15 66 ~ 73 10–29 ~ 11−10 11–11 ~ 5–6 5−1 24 5–9 5–24 5–15 ~ 5–30 5–25 ~ 6–10 209 ~ 213 3–30 ~ 4–5 4–8 ~ 5–14 5–9 21 5–16 5–29 5–24 ~ 6–11 6−3 ~ 6–16 67 ~ 74 10–29 ~ 11−10 11–14 ~ 5–9 5−2 25 5–10 5–26 5–18 ~ 6−2 5–28 ~ 6–12 213 ~ 215 3–30 ~ 4–5 4–6 ~ 5–12 5–9 21 5–16 5–28 5–23 ~ 6–10 6−3 ~ 6–16 67 ~ 74 10–29 ~ 11−10 11–11 ~ 5–7 5−2 26 5–11 5–27 5–18 ~ 6−1 5–28 ~ 6–12 213 ~ 215 Note: SG 0 , 0% increase in precipitation for SG; SG 30 , 30% increase in precipitation for SG; SG 50 , 50% increase in precipitation for SG; AG 0 , 0% increase in precipitation for AG; AG 30 , 30% increase in precipitation for AG; AG 50 , 50% increase in precipitation for AG. 3.3 Survival Under natural precipitation conditions, the survival rates of SG and AG plants began to decrease in late April and early March, respectively, with final survival rates of 49% and 45% (Fig. 3 A, B). Increased precipitation significantly improved the survival rates of both SG and AG plants ( p < 0.05), final survival of SG was significantly lower than that of AG ( p < 0.05, Fig. 3 A, B). 3.4 Morphological characters Under natural precipitation conditions, significant differences were observed in the number of leaves, number of branches, branch length, plant height, leaf area, and root length between SG and AG plants ( p < 0.05) (Fig. 4 A-F). Increased precipitation significantly increased the number of leaves, number of branches, branch length, and plant height of SG plants ( p 0.05). For AG plants, increased precipitation significantly decreased the number of leaves and root length ( p 0.05). 3.5 Dry mass accumulation and allocation Under natural precipitation conditions, the total dry biomass of AG plants (3.598 g) was 6.39 times that of SG plants (0.563 g), and the dry biomass of their reproductive organs (1.16 g) was 19.3 times that of SG plants (0.06 g) (Fig. 5 ). After increased precipitation, the total dry biomass per plant of SG plants increased to 3.817 g (SG 30 ) and 3.888 g (SG 50 ), while that of AG plants increased to 0.775 g (AG 30 ) and 0.938 g (AG 50 ). With the increase in precipitation, the dry biomass of stems in AG plants increased, showing a significant difference compared with natural precipitation conditions ( p < 0.05). The dry biomass of roots, stems, leaves, and fruits in SG plants all increased significantly ( p < 0.05) (Fig. 5 ). With increased precipitation (AG 30 ), SG plants allocated more biomass to stems, reduced biomass allocation to roots and fruits, and had no significant effect on biomass allocation to leaves ( p > 0.05). AG plants allocated more biomass to leaves, reduced biomass allocation to fruits, and exhibited no significant difference in biomass allocation to roots and stems ( p > 0.05) (Fig. 6 ). With the increase in precipitation (AG 50 ), there was no significant effect on the biomass allocation of AG plants ( p > 0.05). SG plants reduced biomass allocation to roots and increased biomass allocation to stems (Fig. 6 ). 3.6 Seed production Under natural precipitation conditions, the number of seeds produced by AG plants was significantly higher than that of SG plants ( p < 0.05). With increased precipitation (AG 50 ), the number of seeds produced by both SG and AG plants increased significantly ( p < 0.05). The number of seeds per plant of AG plants increased from 32 (AG 0 ) to 45 (AG 50 ), and that of SG plants increased from 15 (SG 0 ) to 41 (SG 50 ). With the increase in precipitation, the number of seeds produced by AG plants was significantly higher than that of SG plants ( p < 0.05) (Fig. 7 ). Under natural precipitation, AG plants produced a significantly higher number of seeds per plant than SG plants ( p < 0.05). Increased precipitation(AG 50 ) significantly enhanced seed production in both germination types ( p < 0.05). Specifically, seed number per plant increased from 32 (AG 0 ) to 45 (AG 50 ) in AG plants, and from 15 (SG 0 ) to 41 (SG 50 ) in SG plants. Consequently, AG plants maintained a significantly higher seed output than SG plants across all precipitation levels (( p < 0.05) (Fig. 7 ). 3.7 Offspring seed germination Under natural precipitation conditions, the germination rates of seeds produced by SG and AG plants were 67.51% and 98.34%, respectively. With the increase in precipitation, the germination rate of seeds from SG plants decreased significantly ( p < 0.05). For AG plants, the seed germination rate showed a significant difference only under AG 50 compared with that under natural precipitation conditions ( p < 0.05) (Fig. 8 ). 4. Discussion We hypothesized that the life-history traits of SG plants of H. erectum are more sensitive than those of AG plants in response to increased spring precipitation. Consistent with our hypothesis, the results showed that, under elevated precipitation conditions, the seed yield and total plant biomass of SG plants were significantly higher than those of AG plants. The root length of AG plants increased significantly with increasing precipitation, whereas that of SG plants showed no significant change. Collectively, these variations in root length of H. erectum didn’t support our hypothesis. Under the control treatment, the survival rate of AG plants was lower than that of SG plants. This phenomenon might be attributed to the fact that seedlings germinated in autumn are exposed to low temperatures, frost, and even snow cover during winter. Although some plants can enhance their cold resistance through cold acclimation, prolonged extreme low temperatures or abrupt temperature fluctuations may still lead to cellular dehydration, membrane system damage, metabolic disorders, and even direct mortality[ 3 ]. In addition, some SG and AG plants died in mid-to-late March and early April. This mortality event might be caused by late spring frost: after a temperature rise in spring, seedlings are suddenly exposed to cold waves, making the newly germinated SG seedlings or the dormancy-broken AG seedlings vulnerable to freezing injury. At this stage, plant cells have already become metabolically active, leading to reduced cold resistance, and ice crystal formation consequently results in cellular damage[ 2 ]. Meanwhile, large diurnal temperature fluctuations cause repeated freeze-thaw cycles in plant tissues, which disrupt cell wall integrity and induce water metabolism disorders[ 15 ]. Furthermore, under increased precipitation conditions, the survival rate of SG plants was significantly higher than that of AG plants. At this stage, SG plants were still in the seedling stage, whereas AG plants had entered the vigorous growth phase, characterized by a greater number of leaves and larger plant size. Consequently, AG plants exhibited lower sensitivity to increased precipitation compared with SG plants. Therefore, an increase in early spring precipitation may potentially enhance the survival rate of SG plants in the future. Following water addition, changes in the morphological traits of only a subset of SG and AG plants supported our hypothesis. For SG plants, all morphological traits except root length increased significantly. The leaf number and root length of AG plants decreased significantly with increasing precipitation, indicating that elevated precipitation induced temporary waterlogging in the soil, which in turn caused rhizosphere hypoxia. A study on Picea mariana seedling growth revealed a strong correlation between soil moisture content and the severity of rhizosphere hypoxia. Specifically, soil redox potential following spring snowmelt and precipitation inhibited root growth, thereby increasing seedling mortality[ 16 ]. Roots exhibit hydrotropism; when the surface soil is dry while the deep soil remains moist, roots preferentially extend toward the moist deep soil layers to absorb water, thereby increasing root depth[ 18 ]. The root length of AG H. erectum plants was significantly longer than that of SG conspecifics, indicating that AG plants can absorb water from deep soil layers and thus exhibit lower dependence on surface soil moisture. Therefore, AG plants exhibit a stronger competitive advantage in spring when precipitation is scarce. Following water addition, the seed yield of both SG and AG plants increased significantly, with that of autumn-germinated plants being remarkably higher than that of SG conspecifics, this result didn’t support our hypothesis. Increased precipitation improves soil moisture conditions, supports greater biomass accumulation, and thus ensures the production of more flowers, fruits, and seeds[ 6 ]. In the Great Plains of the United States, water availability directly alleviates the primary limiting factor during the growing season, and increased precipitation significantly enhances the aboveground net primary productivity and seed yield of dominant herbaceous plants[ 14 ]. SG H. erectum plants allocate substantial resources to constructing competitive vegetative organs in the early growing season. In contrast, AG plants have a life cycle spanning two growing seasons and possess a certain reserve of vegetative tissues by spring; thus, they can allocate a larger proportion of the current year’s assimilated resources to reproductive growth earlier. Meanwhile, the increased seed yield induced by elevated precipitation can raise the number of potential seedlings and the extent of seed dispersal, maximize resource utilization, achieve explosive reproduction, replenish the soil seed bank, and serve as a crucial strategy for escaping extreme environmental conditions. In resource-limited environments, the total biomass and organ-specific biomass of annual plants or SG plants are highly positively correlated with water availability[ 13 ]. Following water addition, biomass accumulation in both SG and AG plants increased significantly, which didn’t support our hypothesis. Specifically, elevated precipitation promoted an increase in stem biomass of AG plants, as well as root, stem, leaf, and fruit biomass of SG plants. SG H. erectum plants are at the early stage of their life cycle, and increased precipitation directly alleviates the water demand for germination and early growth; thus, these plants allocate more resources to roots, stems, leaves, and fruits. In contrast, after overwintering, AG plants have already developed well-established root systems and rosette leaves, when precipitation increases in spring, the enhanced stem biomass provides a guarantee for producing more seeds. Compared with AG plants, the biomass of SG plants is more sensitive to increased precipitation, a result that supports our hypothesis. Phenological stages directly affect plant responses to environmental changes; the earlier the phenology, the more sensitive the plant is to the environment[ 28 ]. Different germination strategies represent adaptations to unstable environments. AG plants exhibit vigorous root growth in spring, enabling them to utilize deep soil water and thus showing low dependence on surface precipitation; accordingly, spring precipitation is insufficient to induce a strong response in their biomass accumulation. In contrast, SG plants place all their “bets” on the environmental conditions of the current growing season, and their fitness (e.g., biomass) is therefore inevitably more sensitive to fluctuations in key resources (e.g., precipitation) during the season. Plants adjust the biomass allocation between aboveground and belowground parts during growth to balance resource supply and demand[ 19 ]. Following increased precipitation, the proportions of biomass allocated to leaves and stems in both SG and AG H. erectum plants increased, whereas the proportions of biomass allocated to fruits and roots decreased. According to plant responses to resource allocation, elevated precipitation leads to a decrease in the proportion of root biomass and an increase in the proportion of aboveground biomass, thereby expanding growth space, enhancing competitiveness, and improving productivity[ 17 ]. According to plant responses to resource allocation, elevated precipitation leads to a decrease in the proportion of root biomass and an increase in the proportion of aboveground biomass, thereby expanding growth space, enhancing competitiveness, and improving productivity[ 17 ]. With increased precipitation, AG plants accelerate leaf growth to capture more light, thus gaining a competitive advantage over SG plants. When SG plants are subjected to intense light competition, allocating resources to promote stem elongation and growth represents a crucial survival strategy. The germination season of plants directly determines seed dormancy of offspring, a critical adaptive trait[ 11 ]. In annual plants, the proportion of seed dormancy varies among seeds produced in different germination seasons, and this variation represents a key adaptation to unpredictable precipitation[ 20 ]. SG H. erectum plants produce a higher proportion of non-dormant (ND) seeds, whereas AG plants produce a greater number of physically dormant (PY) seeds. When spring precipitation promotes germination, the non-dormant seeds of SG plants can rapidly occupy habitats and achieve rapid population growth. Seed dormancy ensures seed bank accumulation[ 3 ]. Under adverse environmental conditions such as decreased precipitation, some dormant seeds produced by AG plants enter the soil seed bank. When precipitation increases during the growing season, the biomass of both AG and SG plants increases. Simultaneously, the production of physically dormant (PY) and non-dormant (ND) seeds rises respectively, leading to a corresponding increase in the number of seeds in the seed bank and the number of individuals in the population. Therefore, against the backdrop of increased precipitation, the phenomenon of H. erectum seed germination occurring in both spring and autumn not only mitigates the risk of population extinction under adverse environmental conditions but also enhances the species' competitiveness in plant communities. 5. Conclusions This study systematically investigates the response mechanisms of the life cycle of H. erectum , an early-spring ephemeral plant in the Changbai Mountain region, to increased precipitation. Increased precipitation can extend the life cycle and seed yield of SG and AG plants, enhance the reproductive capacity of the population to a certain extent, and effectively avoid plant death caused by environmental constraints and interspecific competition. Meanwhile, the biomass accumulation of SG and AG plants increases with increasing precipitation. For SG plants, the proportion of biomass allocated to stems and leaves increases, while the biomass allocation to roots and fruits decreases. These results didn’t support the hypothesis that SG plants are more sensitive to water than AG plants, as proposed in our study. Against the backdrop of global climate warming, the biomass and seed yield of SG and AG plants increase, which enhances the competitive advantage of the H. erectum population under the extreme environmental conditions of early spring. After water treatment, the results of the survival rate and morphological characteristics of SG and AG plants support our hypothesis, as the dry biomass of SG and AG plants increases with the increase in precipitation, and the number of seeds produced also increases. AG plants produce more dormant seeds than SG plants, while SG plants produce more non-dormant seeds, which supports our hypothesis. The impact of increased precipitation induced by climate change may alter the number of non-dormant seeds and the proportion of dormant seeds produced by SG and AG plants. Since SG and AG plants can produce both dormant and non-dormant seeds under increased precipitation, they will continue to germinate, grow, and develop with the increase in summer precipitation. Declarations Ethics approval and consent to participate Not applicable. Consent for publication Not applicable. Availability of data and materials All other data generated or analyzed during this study are included in this published article. Competing interests The authors declare that they have no competing interests. Funding This study received funding from the University-Enterprise Cooperation Project (25JBH027L254) and University-Enterprise Cooperation Project (25JBH027L055). Authors' contributions S.L.Y.: Writing-original draft; Writing-review & editing; Funding acquisition R.R.C.: Data curation; Software; Formal analysis X.Y.Y.: Supervision; Visualization Y.T.H.: Project administration Y.J.: Methodology R.J.L.: Conceptualization D.X.J.: Conceptualization Acknowledgements Not applicable. References Akiyama R., Agren J. Conflicting selection on the timing of germination in a natural population of Arabidopsis thaliana. J. Evol. Biol. 2014; 27(1): 193-199. Augspurger C. K. Reconstructing patterns of temperature, phenology, and frost damage over 124 years: spring damage risk is increasing. Ecology. 2013; 94(1): 41-50. Baskin C. C., Baskin J. M. Seeds: ecology, biogeography, and, evolution of dormancy and germination. Academic press; 2000. Cendán C., Sampedro L., Zas R. The maternal environment determines the timing of germination in Pinus pinaster. Environ. Exp. Bot. 2013; 94: 66-72. Chen H. S., Nie Y. P., Wang K. L. Research progress on spatio-temporal heterogeneity of water and plant adaptation mechanisms in karst mountain areas. Acta Ecol. Sinica. 2013; 33(2): 317-326 (in chinese with English abstract). Childs D. Z., Rees M., Rose K. E., et al. Evolution of size–dependent flowering in a variable environment: construction and analysis of a stochastic integral projection model. Proceedings of the Royal Society of London. Series B: Biological Sciences. 2004; 271(1537): 425-434. Cui J. Y., Yan J. Y., Gao Y., et al. Life history characteristics of double-season germinating plants of ephemeral Descurainia sophia . Pratacultural Science. 2025; 42(2): 267-277 (in chinese with English abstract). Cui J. Y. Growth dynamics and resource allocation strategies of spring-germinating and autumn-germinating plants of ephemeral Descurainia sophia . Xinjiang Agricultural University. 2024 (in chinese with English abstract). Donat M. G., Lowry A. L., Alexander L. V., et al. More extreme precipitation in the world’s dry and wet regions. Nat. Clim. Change. 2016; 6(5): 508-513. Flannigan M. D., Wotton B. M., Marshall G. A., et al. Fuel moisture sensitivity to temperature and precipitation: climate change implications. Clim. Change. 2016; 134(1): 59-71. Galloway L. F., Etterson J. R. Transgenerational plasticity is adaptive in the wild. Science, 2007; 318(5853): 1134-1136. Husen A., Iqbal M., Aref I. M. Plant growth and foliar characteristics of faba bean ( Vicia faba L.) as affected by indole-acetic acid under water-sufficient and water-deficient conditions. J. Environ. Biol. 2017; 38(2): 179-185. Huxman T. E., Smith M. D., Fay P. A., et al. Convergence across biomes to a common rain-use efficiency. Nature. 2004; 429(6992): 651-654. Knapp A. K., Fay P. A., Blair J. M., et al. Rainfall variability, carbon cycling, and plant species diversity in a mesic grassland. Science. 2002; 298(5601): 2202-2205. Kreyling J., et al. Water availability and drought responses of tree seedlings at the alpine treeline. J. Ecol. 2012; 100(5): 1231-1240. Lu J. J., Tan D. Y., Baskin J. M., Baskin C. C. Germination season and watering regime, but not seed morph, affect life history traits in a cold desert diaspore-heteromorphic annual. Plos ONE. 2014; 9:e102018. Parent C., Capelli N., Dat J. F. Soil waterlogging and root hypoxia in spring reduce growth and survival of black spruce seedlings. Plant Soil. 2015; 394(1-2), 109-122. Poorter H., Nagel O. The role of biomass allocation in the growth response of plants to different levels of light, CO 2 , nutrients and water: a quantitative review. Aust. J. Plant Physiol. 2000; 27(6): 595-607. Schenk H. J., Jackson R. B. Rooting depths, lateral root spreads and below-ground above-ground allometries of plants in water-limited ecosystems. J. Ecol. 2002; 90(3): 480-494. Shipley B., Meziane D. The balanced‐growth hypothesis and the allometry of leaf and root biomass allocation. Funct. Ecol. 2002; 16(3): 326-331. Venable D. L. Bet hedging in a guild of desert annuals. Ecology, 2007; 88(5): 1086-1090. Wang C. T., Wang Q. J., Shen Z. X., et al. A preliminary study of the effect of simulated precipitation on an apline Kobresia humilis meadow. Acta Pratacult. Sinica. 2003; 12(2): 19-25. Wei J., Chen Q. Research progress on the effects of precipitation changes on grassland shrubification. Chin. Bull. Life Sci. 2025; 32(1): 727-735 (in chinese with English abstract). Yang S. L., Zhou Y. P., Shi X. Flowering phenology and reproductive characteristics of the ephemeral plant Hypecoum erectum L. Acta Bot. Boreali-Occident. Sinica. 2016; 36(9): 1855-1863. Yang X. Y., Ma L., Zhang Z. H., et al. Relationship between growth and development characteristics of alpine meadow plant communities and climatic factors. Acta Ecol. Sinica. 2021; 41(9): 12-24 (in chinese with English abstract). Zhang H., Wang X. P, Zhang Y. F., et al. Responses of plant growth with different life forms to precipitation changes in arid desert areas. Chin. J. Ecol. 2015; 34(7): 1847-1853 (in chinese with English abstract). Zhang L. Y., Chen C. D. On the general characteristics of plant diversity in the Gurbantunggut Desert. Acta Ecol. Sinica. 2002; 22(11): 1923-1932 (in chinese with English abstract). Zhang L., Zhang L. W., Liu H. L., et al. Effects of increased precipitation on the growth of two ephemeral plants in the Gurbantunggut Desert. Chin. J. Appl. Ecol.2020; 31(1): 9-16 (in chinese with English abstract). Zohner C. M., Renner S. S. Common mid-season period of temperature sensitivity across woody species. New Phytol. 2019; 222(1): 176-183. Additional Declarations No competing interests reported. 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16:28:38","extension":"html","order_by":20,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":103471,"visible":true,"origin":"","legend":"","description":"","filename":"earlyproof.html","url":"https://assets-eu.researchsquare.com/files/rs-8417446/v1/8b8141e2d269cb6aa6c9c9c2.html"},{"id":99208117,"identity":"b985c5e8-0003-45b9-8a13-b5e1828f1806","added_by":"auto","created_at":"2025-12-30 07:15:23","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":411512,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eStudy sites (A-C), temperature, precipitation (D), and soil water content (E) from September 10, 2024, to June 10, 2025.\u003c/strong\u003e The shaded areas in D and E indicate winter snowfall. Red arrows (D, E) denote the period when temperatures reach 0℃ or higher and snowmelt begins.\u003c/p\u003e","description":"","filename":"floatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-8417446/v1/2e6b7c531a47c3329eba16e6.png"},{"id":99208118,"identity":"1f5bd095-bcf8-48f0-a527-794116d18939","added_by":"auto","created_at":"2025-12-30 07:15:23","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":311422,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003ePrecipitation treatments (A) and experimental plot design (B) for \u003c/strong\u003e\u003cem\u003e\u003cstrong\u003eH. erectum\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e.\u003c/strong\u003e AG, autumn-germinated plants; SG, spring-germinated plants; CK, natural precipitation without any treatment; W30%, 30% additional precipitation applied the next day after each rainfall event using artificial rain gauges, based on the daily rainfall data recorded by the meteorological station; W50%, 50% additional precipitation applied the next day after each rainfall event using artificial rain gauges, based on the daily rainfall data recorded by the meteorological station.\u003c/p\u003e","description":"","filename":"floatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-8417446/v1/1f6b492755edab2fc65b0c42.png"},{"id":99208121,"identity":"4ad6943b-ed9e-4a09-b990-33c403f83395","added_by":"auto","created_at":"2025-12-30 07:15:23","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":191383,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eEffects of increased precipitation on the survival rate of SG and AG \u003c/strong\u003e\u003cem\u003e\u003cstrong\u003eH. erectum\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e plants.\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNote: G\u003csub\u003e0\u003c/sub\u003e, natural precipitation; G\u003csub\u003e30\u003c/sub\u003e, 30% increase in precipitation based on natural precipitation; G\u003csub\u003e50\u003c/sub\u003e, 50% increase in precipitation based on natural precipitation. Different lowercase letters indicate significant differences among the three water treatments within spring-germinated or AG \u003cem\u003eH. erectum\u003c/em\u003e plants (\u003cem\u003ep\u0026lt;\u003c/em\u003e0.05). Different uppercase letters indicate significant differences between SG and AG \u003cem\u003eH. erectum\u003c/em\u003e plants under the same water treatment (\u003cem\u003ep\u003c/em\u003e\u0026lt;0.05).\u003c/p\u003e","description":"","filename":"floatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-8417446/v1/301b1160dc720f07c89d2298.png"},{"id":99317596,"identity":"3fdc4d9d-fa40-4c8d-8152-121b2454e79d","added_by":"auto","created_at":"2025-12-31 16:30:26","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":80396,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eEffects of increased precipitation on the number of leaves (A), number of branches (B), branch length (C), plant height (D), leaf area (E), and root length (F) of SG and AG \u003c/strong\u003e\u003cem\u003e\u003cstrong\u003eH. erectum\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e plants.\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNote: Different lowercase letters indicate significant differences among the 3 water treatments within SG and AG \u003cem\u003eH. erectum\u003c/em\u003e plants (\u003cem\u003ep\u003c/em\u003e\u0026lt;0.05). Different uppercase letters indicate significant differences between SG and AG \u003cem\u003eH. erectum\u003c/em\u003e plants under the same water treatment (\u003cem\u003ep\u003c/em\u003e\u0026lt;0.05).\u003c/p\u003e","description":"","filename":"floatimage4.png","url":"https://assets-eu.researchsquare.com/files/rs-8417446/v1/9036d6075b97b2f4bc08b16b.png"},{"id":99208135,"identity":"e096fc48-0e76-4c0e-85b6-8e61260752cc","added_by":"auto","created_at":"2025-12-30 07:15:24","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":67999,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eEffects of increased precipitation on the dry weight of SG and AG \u003c/strong\u003e\u003cem\u003e\u003cstrong\u003eH. erectum\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003eplants.\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNote: Different lowercase letters indicate significant differences among the 3 water treatments within SG and AG \u003cem\u003eH. erectum\u003c/em\u003e plants (\u003cem\u003ep\u003c/em\u003e\u0026lt;0.05). Different uppercase letters indicate significant differences between SG and AG \u003cem\u003eH. erectum \u003c/em\u003eplants under the same water treatment (\u003cem\u003ep\u003c/em\u003e\u0026lt;0.05).\u003c/p\u003e","description":"","filename":"floatimage5.png","url":"https://assets-eu.researchsquare.com/files/rs-8417446/v1/25e93a28790db02718033757.png"},{"id":99208136,"identity":"c9c47645-c569-4d8c-a66e-38dbbf5799b8","added_by":"auto","created_at":"2025-12-30 07:15:24","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":73582,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eEffects of increased precipitation on the biomass allocation of SG and AG \u003c/strong\u003e\u003cem\u003e\u003cstrong\u003eH. erectum\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e plants.\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNote: Different lowercase letters indicate significant differences among the 3 water treatments within SG and AG \u003cem\u003eH. erectum\u003c/em\u003e plants (\u003cem\u003ep\u003c/em\u003e\u0026lt;0.05). Different uppercase letters indicate significant differences between SG and AG \u003cem\u003eH. erectum \u003c/em\u003eplants under the same water treatment (\u003cem\u003ep\u003c/em\u003e\u0026lt;0.05).\u003c/p\u003e","description":"","filename":"floatimage6.png","url":"https://assets-eu.researchsquare.com/files/rs-8417446/v1/47119f7eb02d05c174d7c8f8.png"},{"id":99319548,"identity":"210e6414-3c6f-45e5-b161-5214c9da26a5","added_by":"auto","created_at":"2025-12-31 16:37:27","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":34493,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eEffects of increased precipitation on the seed number of SG and AG \u003c/strong\u003e\u003cem\u003e\u003cstrong\u003eH. erectum\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e plants.\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNote: Different lowercase letters indicate significant differences among the 3 water treatments within SG and AG \u003cem\u003eH. erectum\u003c/em\u003e plants (\u003cem\u003ep\u003c/em\u003e\u0026lt;0.05). Different uppercase letters indicate significant differences between SG and AG \u003cem\u003eH. erectum\u003c/em\u003eplants under the same water treatment (\u003cem\u003ep\u003c/em\u003e\u0026lt;0.05).\u003c/p\u003e","description":"","filename":"floatimage7.png","url":"https://assets-eu.researchsquare.com/files/rs-8417446/v1/b4e6bb13dc30fe859fd2e7b6.png"},{"id":99208129,"identity":"c545174b-b93a-4ff6-8a09-2faa7fb1e65d","added_by":"auto","created_at":"2025-12-30 07:15:24","extension":"png","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":59259,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eEffects of precipitation treatments on the germination characteristics of SG and AG \u003c/strong\u003e\u003cem\u003e\u003cstrong\u003eH. erectum\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e plants under 25/15 ℃ conditions.\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNote: Different lowercase letters indicate significant differences among the three water treatments within SG and AG \u003cem\u003eH. erectum\u003c/em\u003e (\u003cem\u003ep\u003c/em\u003e\u0026lt;0.05). Different uppercase letters indicate significant differences between SG and AG \u003cem\u003eH. erectum\u003c/em\u003eplants under the same water treatment (\u003cem\u003ep\u003c/em\u003e\u0026lt;0.05).\u003c/p\u003e","description":"","filename":"floatimage8.png","url":"https://assets-eu.researchsquare.com/files/rs-8417446/v1/0a89a2b0e3c82f98012fa8de.png"},{"id":101280930,"identity":"13c3835f-bea6-463f-81cc-8948cbd91bed","added_by":"auto","created_at":"2026-01-28 05:10:25","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2439820,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8417446/v1/ce7f4753-3135-4d04-9143-b2952f72e1d5.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"\u003cp\u003eEffects of increased precipitation and on the life history of spring- and autumn-germinated plants of the annual Hypecoum erectum L.\u003c/p\u003e","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eWith global climate warming, changes in precipitation characteristics represent one of the most critical aspects of global climate change, exerting negative and potential impacts on global terrestrial ecosystems and biodiversity[9]. Plants are key components of terrestrial ecosystems, and precipitation change directly regulates plant growth and reproduction[22]. The impact of increased/decreased precipitation during the growing season on plant growth is one of the critical issues in ecological research[25]. As a core environmental factor regulating plant growth and development, the spatiotemporal variation of precipitation profoundly shapes plant life-history strategies[5].\u003c/p\u003e\n\u003cp\u003eAs a key environmental factor for plant germination and growth, precipitation exerts profound impacts on plant physiological and ecological processes, dry matter accumulation and allocation, as well as the structure and function of ecosystems[24]. Increased precipitation not only promotes seedling germination but also exhibits a significantly positive correlation with plant growth[21]. During the plant vegetative growth stage, increased precipitation can accelerate the growth of new leaves and branches in ephemeral plants, and significantly affect the phenological characteristics, biomass accumulation and allocation of dominant ephemeral plant species, as well as plant diversity[27]. Furthermore, the maternal plant environment can also induce changes in seed germination potential and germination rate[4]. Seeds produced in wet seasons often are more dormant than those produced in dry warm years[3]. Therefore, against the backdrop of altered precipitation patterns, investigating the mechanisms underlying plant biomass accumulation and allocation as well as seed responses to precipitation changes is of great significance.\u003c/p\u003e\n\u003cp\u003eIn arid and semi-arid regions, water is the primary limiting factor for plant growth and development, while precipitation (including snowmelt) serves as the main source of water[10]. As a unique plant group in this region, ephemeral plants can germinate utilizing winter snowmelt and early spring precipitation, grow rapidly, efficiently capture light, allocate a high proportion of biomass to seeds[26], and complete their life cycle before the onset of summer, thus being highly sensitive to changes in precipitation amount.\u003c/p\u003e\n\u003cp\u003eSeed germination marks the initiation of the life cycle of annual plants, and germination timing is a specific indicator of seed germination behavior. Variations in germination timing exert significant impacts on plant growth, life-history traits, competitive ability, and reproductive output[1]. Some annual plants exhibit two germination seasons: autumn and spring, and germination timing is a consequence of long-term adaptation to environmental conditions[7]. When autumn precipitation is sufficient, seeds germinate and overwinter as rosettes, completing their life cycle in the following spring[8]. When autumn precipitation decreases, seeds remain dormant until the following spring, when snowmelt moistens the soil, and then rapidly complete their life cycle. Significant differences exist in phenology, survival rate, morphological characteristics, dry matter accumulation and allocation, as well as seed dormancy traits between spring- and autumn-germinated plants of the same species. The \u0026ldquo;bet-hedging\u0026rdquo; germination strategy of\u0026nbsp;SG and AG\u0026nbsp;plants reflects the plants\u0026apos; response and adaptation strategies to environmental conditions in different seasons.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eHypecoum erectum\u0026nbsp;\u003c/em\u003eL. is a common ephemeral plant native to the Changbai Mountain region of China, characterized by\u0026nbsp;SG and AG\u0026nbsp;habits and biannual flowering, and is mainly distributed in Russia, Mongolia, and China.\u003cem\u003e\u0026nbsp;\u003c/em\u003eIt is widely distributed in the Changbai Mountains region of Jilin Province in China, with its vegetation coverage reaching 10%-12% in this area in May[23]. SG plants initiate growth when temperatures rise in spring, utilizing sufficient water and light during this season for rapid growth and reproduction. AG plants germinate in autumn and grow by utilizing the relatively mild climate and sufficient light during this season[12]. Ephemeral plants are more sensitive to nitrogen deposition than perennial plants. Therefore, based on the differences in the life cycles of\u0026nbsp;SG and AG\u0026nbsp;plants, we hypothesize that the life-history traits of SG \u003cem\u003eH. erectum\u003c/em\u003e are more sensitive to precipitation than those of AG individuals. To test this hypothesis, we conducted a comparative analysis of the phenology, survival rate, morphological characteristics, and biomass accumulation and allocation between\u0026nbsp;SG and AG\u0026nbsp;plants of \u003cem\u003eH. erectum\u003c/em\u003e in the Changbai Mountain region. In addition, we conducted germination experiments on seeds collected under all experimental conditions to determine the effects of maternal plant environment on seed dormancy and dormancy ratio.\u003c/p\u003e"},{"header":"2. Materials and methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\n \u003ch2\u003e2.1 Seed germination of study species\u003c/h2\u003e\n \u003cp\u003eFreshly harvested seeds of \u003cem\u003eH. erectum\u003c/em\u003e germinate at a rate of 25% under the condition of 25/10℃, and the non-germinated seeds are water-impermeable, thus exhibiting physical dormancy. Freshly harvested seeds buried in the original habitat had a germination rate of 20% from July to early November, with an additional 5% germinating by March of the following year. This is because 25% of the seeds buried in the soil are water-permeable, therefore, we speculate that the soil moisture in autumn is insufficient to trigger germination of all water-permeable seeds, while the remaining 5% of water-permeable seeds require increased soil moisture in late winter to germinate.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec4\" class=\"Section2\"\u003e\n \u003ch2\u003e2.2 Study site\u003c/h2\u003e\n \u003cp\u003eThe Changbai Mountains represent the highest mountain range in Northeast Asia, and the study area is located on the northern slope of the Changbai Mountains (127\u0026deg;40\u0026prime;-128\u0026deg;16\u0026prime; E, 41\u0026deg;35\u0026prime;-42\u0026deg;25\u0026prime;N) (Fig. \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003eA-C). This region holds extremely important status in terms of geography, ecology, and hydrology, featuring a typical temperate continental mountain climate. The annual average temperature ranges from 3 ℃ to 7 ℃, decreasing continuously with increasing altitude, while the annual average precipitation is 600\u0026ndash;1400 mm (Fig. \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003eD) and the annual evaporation is 500\u0026ndash;800 mm. During the growing season, the average soil volumetric water content ranges from 40% to 60% (Fig. \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003eE). The region is covered by snow in winter, with a stable snow cover period of up to 6 months and an average snow depth of 30\u0026ndash;50 cm. Winter snowfall accounts for approximately 10% of the annual precipitation. Snowmelt in early spring provides favorable moisture conditions for the growth and development of ephemeral plants in the short spring season.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec5\" class=\"Section2\"\u003e\n \u003ch2\u003e2.3 Experimental procedure\u003c/h2\u003e\n \u003cp\u003eThe experimental materials used in this study were mature seeds of \u003cem\u003eH. erectum\u003c/em\u003e samples were collected from the Changbai Mountain Experimental Area in northeastern China in June 2024 and June 2025. The sampling site is a non-nature reserve area, where \u003cem\u003eH. erectum\u003c/em\u003e is a common wild herbaceous plant and is not listed in the national or local List of Key Protected Wild Plants. In accordance with the relevant provisions of the Regulations of the People\u0026apos;s Republic of China on the Protection of Wild Plants, no special collection permit was required for this sampling. The experimental seeds were identified by Professor Wu Shixiong from Changchun University. All seeds were collected from maternal plants, ensuring accurate species classification. The corresponding voucher specimens of the plants (Accession No.: CCU-WSX-2023-63) are currently deposited in the Herbarium of the College of Landscape Architecture, Changchun University.\u003c/p\u003e\n \u003cp\u003eTo simulate the precipitation in the Changbai Mountain region under current, future, and extreme scenarios, we conducted precipitation treatments on seeds of SG and AG plants based on the actual spring and summer precipitation in the study area in 2023. The treatments included 0% increase in precipitation (SG\u003csub\u003e0\u003c/sub\u003e, AG\u003csub\u003e0\u003c/sub\u003e), 30% increase in precipitation (SG\u003csub\u003e30\u003c/sub\u003e, AG\u003csub\u003e30)\u003c/sub\u003e, and 50% increase in precipitation (SG\u003csub\u003e50\u003c/sub\u003e, AG\u003csub\u003e50\u003c/sub\u003e) (Fig. \u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003eA). 6 treatment groups were established in the experiment, with 12 plots (1 m \u0026times; 1 m) per group (5 plots for phenological observation, 6 plots for trait determination and biomass sampling, and 1 plot as a reserve). To reduce inter-treatment interference, each treatment was spaced 2 m apart, and a 0.5 m deep impermeable layer (plastic sheet) was buried 1 m away between adjacent plots (Fig. \u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003eB). The plots were distributed in relatively uniform and flat inter-dunal lowlands. In addition, to prevent competition from other plants, manual weeding was conducted in the plots in November 2024 and early April 2025 after snowmelt. All plots were surrounded by black plastic film, which was buried 50 cm deep into the soil and protruded 10 cm above the ground to avoid runoff of irrigation water into non-irrigated areas. Based on the daily precipitation data from climate and soil moisture monitoring devices, the treatments with 30% and 50% increases in precipitation were implemented on the 2 d after each precipitation event.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec6\" class=\"Section2\"\u003e\n \u003ch2\u003e2.4 Measurements and sampling\u003c/h2\u003e\n \u003cdiv id=\"Sec7\" class=\"Section3\"\u003e\n \u003ch2\u003e2.4.1 Phenology\u003c/h2\u003e\n \u003cp\u003eFollowing the phenological recording method described by Lu et al. (2014)[\u003cspan class=\"CitationRef\"\u003e16\u003c/span\u003e], during the growing season of SG and AG \u003cem\u003eH. erectum\u003c/em\u003e plants, observations were conducted and recorded in the 5 phenological observation plots of each treatment throughout the entire life cycle from seed germination to plant withering. The recorded phenological traits included emergence date (i.e., the number of days until all seeds in each plot had emerged), leafing date (the number of days until all plants in each plot had four leaves), first flowering date (the number of days until 25% of the plants in each plot had flowered), peak flowering date (the number of days until 50% of the plants in each plot had flowered), last flowering date (the number of days until 95% of the plants in each plot had flowered), fruiting date (the number of days until the first fruit on all plants in each plot turned brown), and withering date (the number of days until all plants in each plot had withered). Additionally, flowering duration (the number of days from the first flowering date to the last flowering date) and life cycle (the number of days from the emergence date to the withering date) were calculated.\u003c/p\u003e\n \u003c/div\u003e\n \u003cdiv id=\"Sec8\" class=\"Section3\"\u003e\n \u003ch2\u003e2.4.2 Survivorship\u003c/h2\u003e\n \u003cp\u003eDuring the SG and AG seasons of \u003cem\u003eH. erectum\u003c/em\u003e, the number of surviving plants in the corresponding plots was monitored regularly across the 6 treatment groups. The monitoring interval was set at 7 d, continuing until the end of the fruit harvesting period.\u003c/p\u003e\n \u003c/div\u003e\n \u003cdiv id=\"Sec9\" class=\"Section3\"\u003e\n \u003ch2\u003e2.4.3 Morphological characters\u003c/h2\u003e\n \u003cp\u003eAt plant maturity, measurements were conducted across 36 quadrats subjected to 6 different treatments (with 6 quadrats per treatment). Plant height, taproot length, and branch length were measured using a vernier caliper (Mitutoyo-500-196-30). Leaf area was quantified with a portable leaf area meter (LI-3000C). Additionally, the number of leaves, the number of branches, and the number of ramifications were recorded.\u003c/p\u003e\n \u003c/div\u003e\n \u003cdiv id=\"Sec10\" class=\"Section3\"\u003e\n \u003ch2\u003e2.4.4 Dry mass accumulation and allocation\u003c/h2\u003e\n \u003cp\u003e\u003cem\u003eH. erectum\u003c/em\u003e plants in 36 plots across 6 treatment groups (including both SG and AG plants) were selected as the research objects. Sample collection strictly followed the ripeness standard of pods turning yellow but not dehiscing, and the whole-plant harvesting date was determined according to the fruit maturation time. When excavating, intact root systems were obtained by taking soil cores centered on each plant with a radius of 20 cm and a depth of 50 cm (fully considering the root length of 30\u0026ndash;40 cm). In the laboratory, plants were separated into four components: roots, stems, leaves, and fruits. After oven-drying at 80℃ for 48 h, each component was weighed using a Sartorius BS210S electronic balance (0.0001 g precision). Total biomass was calculated as the sum of roots, stems, leaves, and reproductive organs (flowers, fruits, and seeds). The biomass allocation of roots, stems, leaves, and fruits was expressed as percentages.\u003c/p\u003e\n \u003c/div\u003e\n \u003cdiv id=\"Sec11\" class=\"Section3\"\u003e\n \u003ch2\u003e2.4.5 Offspring seed germination\u003c/h2\u003e\n \u003cp\u003eMature seeds of SG and AG \u003cem\u003eH. erectum\u003c/em\u003e plants were collected from different treatments on June 15, 2025, as materials for the germination experiment. The germination experiment started on June 20, 2025, with 4 replicates per treatment and 30 seeds per replicate. Seeds were evenly sown in 90 mm Petri dishes lined with 2 layers of moist filter paper (moistened with 3 mL of distilled water) and incubated under conditions of 25/15℃ and a 12/12 h light/dark cycle. During the 30 d experiment, germinated seeds (marked by a radicle protruding 2 mm) were recorded and removed daily, with distilled water supplemented to compensate for evaporation loss. The final germination percentage (FPG) was calculated using the formula: FPG\u0026thinsp;=\u0026thinsp;GN / SN (GN: total number of germinated seeds; SN: number of viable seeds). All non-germinated seeds were tested for viability by staining with 0.5% TTC solution at 25℃ for 24 h, and seeds with embryos stained red or pink were deemed viable.\u003c/p\u003e\n \u003c/div\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec12\" class=\"Section2\"\u003e\n \u003ch2\u003e2.5 Statistical analysis\u003c/h2\u003e\n \u003cp\u003eOne-way analysis of variance (One-way ANOVA) was used to analyze the effects of year, nitrogen addition, and nitrogen-water interaction on plant survival rate, morphological traits, biomass, and seed germination characteristics. Based on the results of multi-factor analysis of variance (ANOVA), the Tukey\u0026apos;s test was used for multiple comparisons of growth and biomass variables with significant differences to identify significant differences among different treatments. All data analyses were performed using SPSS 24.0 software, and graphs were plotted with Origin 2018 software (Origin Lab, Northampton, MA, USA).\u003c/p\u003e\n\u003c/div\u003e"},{"header":"3. Results","content":"\u003cdiv id=\"Sec14\" class=\"Section2\"\u003e\n \u003ch2\u003e3.1 Precipitation and temperature\u003c/h2\u003e\n \u003cp\u003eDuring the observation period, the daily average temperature gradually decreased from October 2024, reached the minimum (-20℃) on January 9, 2025, and rapidly rose to 26℃ on July 9, 2025 (Fig. \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003eD). The snowmelt process began on March 10, 2025. As the snow cover started to melt, soil moisture increased and remained above 40% from mid-March onward (Fig. \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003eE).\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec15\" class=\"Section2\"\u003e\n \u003ch2\u003e3.2 Phenology\u003c/h2\u003e\n \u003cp\u003eUnder natural precipitation conditions, the phenological phases of AG plants were earlier than those of SG plants, while their life cycle was longer. After increasing precipitation, both SG and AG plants showed phenological delays. The first flowering date was extended by 1 d, and the last flowering date was prolonged by 1\u0026ndash;3 d (Table \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e\n \u003cp\u003e\u003c/p\u003e\u0026nbsp;\u003ctable id=\"Tab1\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eEffects of increased nitrogen, and precipitation plus nitrogen treatments on phenology of SG and AG plants of \u003cem\u003eH. erectum\u003c/em\u003e\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003ePhenology\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eEmergence\u003c/p\u003e\n \u003cp\u003edate (month-day)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eLeafing\u003c/p\u003e\n \u003cp\u003edate\u003c/p\u003e\n \u003cp\u003e(month-day)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eFirst flowering date\u003c/p\u003e\n \u003cp\u003e(month-day)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eFlowering duration (d)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003ePeak flowering date\u003c/p\u003e\n \u003cp\u003e(month-day)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eLast flowering date\u003c/p\u003e\n \u003cp\u003e(month-day)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eFruiting\u003c/p\u003e\n \u003cp\u003edate\u003c/p\u003e\n \u003cp\u003e(month-day)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eWithering date\u003c/p\u003e\n \u003cp\u003e(month-day)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eLife\u003c/p\u003e\n \u003cp\u003ecycle\u003c/p\u003e\n \u003cp\u003e(d)\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" rowspan=\"6\"\u003e\n \u003cp\u003eSG\u003csub\u003e0\u003c/sub\u003e\u003c/p\u003e\n \u003cp\u003eAG\u003csub\u003e0\u003c/sub\u003e\u003c/p\u003e\n \u003cp\u003eSG\u003csub\u003e30\u003c/sub\u003e\u003c/p\u003e\n \u003cp\u003eAG\u003csub\u003e30\u003c/sub\u003e\u003c/p\u003e\n \u003cp\u003eSG\u003csub\u003e50\u003c/sub\u003e\u003c/p\u003e\n \u003cp\u003eAG\u003csub\u003e50\u003c/sub\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3\u0026ndash;30\u0026thinsp;~\u0026thinsp;4\u0026ndash;5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e4\u0026ndash;6\u0026thinsp;~\u0026thinsp;5\u0026ndash;12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5\u0026ndash;8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e20\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5\u0026ndash;15\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5\u0026ndash;27\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5\u0026ndash;23\u0026thinsp;~\u0026thinsp;6\u0026ndash;10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6\u0026minus;2\u0026thinsp;~\u0026thinsp;6\u0026ndash;15\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e66\u0026thinsp;~\u0026thinsp;73\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e10\u0026ndash;29\u0026thinsp;~\u0026thinsp;11\u0026minus;10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e11\u0026ndash;11\u0026thinsp;~\u0026thinsp;5\u0026ndash;6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5\u0026minus;1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e24\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5\u0026ndash;9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5\u0026ndash;24\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5\u0026ndash;15\u0026thinsp;~\u0026thinsp;5\u0026ndash;30\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5\u0026ndash;25\u0026thinsp;~\u0026thinsp;6\u0026ndash;10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e209\u0026thinsp;~\u0026thinsp;213\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3\u0026ndash;30\u0026thinsp;~\u0026thinsp;4\u0026ndash;5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e4\u0026ndash;8\u0026thinsp;~\u0026thinsp;5\u0026ndash;14\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5\u0026ndash;9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e21\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5\u0026ndash;16\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5\u0026ndash;29\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5\u0026ndash;24\u0026thinsp;~\u0026thinsp;6\u0026ndash;11\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6\u0026minus;3\u0026thinsp;~\u0026thinsp;6\u0026ndash;16\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e67\u0026thinsp;~\u0026thinsp;74\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e10\u0026ndash;29\u0026thinsp;~\u0026thinsp;11\u0026minus;10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e11\u0026ndash;14\u0026thinsp;~\u0026thinsp;5\u0026ndash;9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5\u0026minus;2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e25\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5\u0026ndash;10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5\u0026ndash;26\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5\u0026ndash;18\u0026thinsp;~\u0026thinsp;6\u0026minus;2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5\u0026ndash;28\u0026thinsp;~\u0026thinsp;6\u0026ndash;12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e213\u0026thinsp;~\u0026thinsp;215\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3\u0026ndash;30\u0026thinsp;~\u0026thinsp;4\u0026ndash;5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e4\u0026ndash;6\u0026thinsp;~\u0026thinsp;5\u0026ndash;12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5\u0026ndash;9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e21\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5\u0026ndash;16\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5\u0026ndash;28\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5\u0026ndash;23\u0026thinsp;~\u0026thinsp;6\u0026ndash;10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6\u0026minus;3\u0026thinsp;~\u0026thinsp;6\u0026ndash;16\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e67\u0026thinsp;~\u0026thinsp;74\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e10\u0026ndash;29\u0026thinsp;~\u0026thinsp;11\u0026minus;10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e11\u0026ndash;11\u0026thinsp;~\u0026thinsp;5\u0026ndash;7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5\u0026minus;2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e26\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5\u0026ndash;11\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5\u0026ndash;27\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5\u0026ndash;18\u0026thinsp;~\u0026thinsp;6\u0026minus;1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5\u0026ndash;28\u0026thinsp;~\u0026thinsp;6\u0026ndash;12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e213\u0026thinsp;~\u0026thinsp;215\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003ctfoot\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"10\"\u003eNote: SG\u003csub\u003e0\u003c/sub\u003e, 0% increase in precipitation for SG; SG\u003csub\u003e30\u003c/sub\u003e, 30% increase in precipitation for SG; SG\u003csub\u003e50\u003c/sub\u003e, 50% increase in precipitation for SG; AG\u003csub\u003e0\u003c/sub\u003e, 0% increase in precipitation for AG; AG\u003csub\u003e30\u003c/sub\u003e, 30% increase in precipitation for AG; AG\u003csub\u003e50\u003c/sub\u003e, 50% increase in precipitation for AG.\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tfoot\u003e\n \u003c/table\u003e\n \u003cp\u003e\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec16\" class=\"Section2\"\u003e\n \u003ch2\u003e3.3 Survival\u003c/h2\u003e\n \u003cp\u003eUnder natural precipitation conditions, the survival rates of SG and AG plants began to decrease in late April and early March, respectively, with final survival rates of 49% and 45% (Fig. \u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003eA, B). Increased precipitation significantly improved the survival rates of both SG and AG plants (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05), final survival of SG was significantly lower than that of AG (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05, Fig. \u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003eA, B).\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec17\" class=\"Section2\"\u003e\n \u003ch2\u003e3.4 Morphological characters\u003c/h2\u003e\n \u003cp\u003eUnder natural precipitation conditions, significant differences were observed in the number of leaves, number of branches, branch length, plant height, leaf area, and root length between SG and AG plants (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05) (Fig. \u003cspan class=\"InternalRef\"\u003e4\u003c/span\u003eA-F). Increased precipitation significantly increased the number of leaves, number of branches, branch length, and plant height of SG plants (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05). With the increase in precipitation, there was no significant effect on the root length of SG plants (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026gt;\u0026thinsp;0.05). For AG plants, increased precipitation significantly decreased the number of leaves and root length (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05). However, it had no significant effects on the number of branches, branch length, or plant height (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026gt;\u0026thinsp;0.05).\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec18\" class=\"Section2\"\u003e\n \u003ch2\u003e3.5 Dry mass accumulation and allocation\u003c/h2\u003e\n \u003cp\u003eUnder natural precipitation conditions, the total dry biomass of AG plants (3.598 g) was 6.39 times that of SG plants (0.563 g), and the dry biomass of their reproductive organs (1.16 g) was 19.3 times that of SG plants (0.06 g) (Fig. \u003cspan class=\"InternalRef\"\u003e5\u003c/span\u003e). After increased precipitation, the total dry biomass per plant of SG plants increased to 3.817 g (SG\u003csub\u003e30\u003c/sub\u003e) and 3.888 g (SG\u003csub\u003e50\u003c/sub\u003e), while that of AG plants increased to 0.775 g (AG\u003csub\u003e30\u003c/sub\u003e) and 0.938 g (AG\u003csub\u003e50\u003c/sub\u003e). With the increase in precipitation, the dry biomass of stems in AG plants increased, showing a significant difference compared with natural precipitation conditions (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05). The dry biomass of roots, stems, leaves, and fruits in SG plants all increased significantly (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05) (Fig. \u003cspan class=\"InternalRef\"\u003e5\u003c/span\u003e).\u003c/p\u003e\n \u003cp\u003eWith increased precipitation (AG\u003csub\u003e30\u003c/sub\u003e), SG plants allocated more biomass to stems, reduced biomass allocation to roots and fruits, and had no significant effect on biomass allocation to leaves (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026gt;\u0026thinsp;0.05). AG plants allocated more biomass to leaves, reduced biomass allocation to fruits, and exhibited no significant difference in biomass allocation to roots and stems (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026gt;\u0026thinsp;0.05) (Fig. \u003cspan class=\"InternalRef\"\u003e6\u003c/span\u003e). With the increase in precipitation (AG\u003csub\u003e50\u003c/sub\u003e), there was no significant effect on the biomass allocation of AG plants (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026gt;\u0026thinsp;0.05). SG plants reduced biomass allocation to roots and increased biomass allocation to stems (Fig. \u003cspan class=\"InternalRef\"\u003e6\u003c/span\u003e).\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec19\" class=\"Section2\"\u003e\n \u003ch2\u003e3.6 Seed production\u003c/h2\u003e\n \u003cp\u003eUnder natural precipitation conditions, the number of seeds produced by AG plants was significantly higher than that of SG plants (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05). With increased precipitation (AG\u003csub\u003e50\u003c/sub\u003e), the number of seeds produced by both SG and AG plants increased significantly (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05). The number of seeds per plant of AG plants increased from 32 (AG\u003csub\u003e0\u003c/sub\u003e) to 45 (AG\u003csub\u003e50\u003c/sub\u003e), and that of SG plants increased from 15 (SG\u003csub\u003e0\u003c/sub\u003e) to 41 (SG\u003csub\u003e50\u003c/sub\u003e). With the increase in precipitation, the number of seeds produced by AG plants was significantly higher than that of SG plants (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05) (Fig. \u003cspan class=\"InternalRef\"\u003e7\u003c/span\u003e).\u003c/p\u003e\n \u003cp\u003eUnder natural precipitation, AG plants produced a significantly higher number of seeds per plant than SG plants (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05). Increased precipitation(AG\u003csub\u003e50\u003c/sub\u003e) significantly enhanced seed production in both germination types (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05). Specifically, seed number per plant increased from 32 (AG\u003csub\u003e0\u003c/sub\u003e) to 45 (AG\u003csub\u003e50\u003c/sub\u003e) in AG plants, and from 15 (SG\u003csub\u003e0\u003c/sub\u003e) to 41 (SG\u003csub\u003e50\u003c/sub\u003e) in SG plants. Consequently, AG plants maintained a significantly higher seed output than SG plants across all precipitation levels ((\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05) (Fig. \u003cspan class=\"InternalRef\"\u003e7\u003c/span\u003e).\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec20\" class=\"Section2\"\u003e\n \u003ch2\u003e3.7 Offspring seed germination\u003c/h2\u003e\n \u003cp\u003eUnder natural precipitation conditions, the germination rates of seeds produced by SG and AG plants were 67.51% and 98.34%, respectively. With the increase in precipitation, the germination rate of seeds from SG plants decreased significantly (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05). For AG plants, the seed germination rate showed a significant difference only under AG\u003csub\u003e50\u003c/sub\u003e compared with that under natural precipitation conditions (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05) (Fig. \u003cspan class=\"InternalRef\"\u003e8\u003c/span\u003e).\u003c/p\u003e\n\u003c/div\u003e"},{"header":"4. Discussion","content":"\u003cp\u003eWe hypothesized that the life-history traits of SG plants of \u003cem\u003eH. erectum\u003c/em\u003e are more sensitive than those of AG plants in response to increased spring precipitation. Consistent with our hypothesis, the results showed that, under elevated precipitation conditions, the seed yield and total plant biomass of SG plants were significantly higher than those of AG plants. The root length of AG plants increased significantly with increasing precipitation, whereas that of SG plants showed no significant change. Collectively, these variations in root length of \u003cem\u003eH. erectum\u003c/em\u003e didn\u0026rsquo;t support our hypothesis.\u003c/p\u003e\n\u003cp\u003eUnder the control treatment, the survival rate of AG plants was lower than that of SG plants. This phenomenon might be attributed to the fact that seedlings germinated in autumn are exposed to low temperatures, frost, and even snow cover during winter. Although some plants can enhance their cold resistance through cold acclimation, prolonged extreme low temperatures or abrupt temperature fluctuations may still lead to cellular dehydration, membrane system damage, metabolic disorders, and even direct mortality[\u003cspan class=\"CitationRef\"\u003e3\u003c/span\u003e]. In addition, some SG and AG plants died in mid-to-late March and early April. This mortality event might be caused by late spring frost: after a temperature rise in spring, seedlings are suddenly exposed to cold waves, making the newly germinated SG seedlings or the dormancy-broken AG seedlings vulnerable to freezing injury. At this stage, plant cells have already become metabolically active, leading to reduced cold resistance, and ice crystal formation consequently results in cellular damage[\u003cspan class=\"CitationRef\"\u003e2\u003c/span\u003e]. Meanwhile, large diurnal temperature fluctuations cause repeated freeze-thaw cycles in plant tissues, which disrupt cell wall integrity and induce water metabolism disorders[\u003cspan class=\"CitationRef\"\u003e15\u003c/span\u003e]. Furthermore, under increased precipitation conditions, the survival rate of SG plants was significantly higher than that of AG plants. At this stage, SG plants were still in the seedling stage, whereas AG plants had entered the vigorous growth phase, characterized by a greater number of leaves and larger plant size. Consequently, AG plants exhibited lower sensitivity to increased precipitation compared with SG plants. Therefore, an increase in early spring precipitation may potentially enhance the survival rate of SG plants in the future.\u003c/p\u003e\n\u003cp\u003eFollowing water addition, changes in the morphological traits of only a subset of SG and AG plants supported our hypothesis. For SG plants, all morphological traits except root length increased significantly. The leaf number and root length of AG plants decreased significantly with increasing precipitation, indicating that elevated precipitation induced temporary waterlogging in the soil, which in turn caused rhizosphere hypoxia. A study on \u003cem\u003ePicea mariana\u003c/em\u003e seedling growth revealed a strong correlation between soil moisture content and the severity of rhizosphere hypoxia. Specifically, soil redox potential following spring snowmelt and precipitation inhibited root growth, thereby increasing seedling mortality[\u003cspan class=\"CitationRef\"\u003e16\u003c/span\u003e]. Roots exhibit hydrotropism; when the surface soil is dry while the deep soil remains moist, roots preferentially extend toward the moist deep soil layers to absorb water, thereby increasing root depth[\u003cspan class=\"CitationRef\"\u003e18\u003c/span\u003e]. The root length of AG \u003cem\u003eH. erectum\u003c/em\u003e plants was significantly longer than that of SG conspecifics, indicating that AG plants can absorb water from deep soil layers and thus exhibit lower dependence on surface soil moisture. Therefore, AG plants exhibit a stronger competitive advantage in spring when precipitation is scarce.\u003c/p\u003e\n\u003cp\u003eFollowing water addition, the seed yield of both SG and AG plants increased significantly, with that of autumn-germinated plants being remarkably higher than that of SG conspecifics, this result didn\u0026rsquo;t support our hypothesis. Increased precipitation improves soil moisture conditions, supports greater biomass accumulation, and thus ensures the production of more flowers, fruits, and seeds[\u003cspan class=\"CitationRef\"\u003e6\u003c/span\u003e]. In the Great Plains of the United States, water availability directly alleviates the primary limiting factor during the growing season, and increased precipitation significantly enhances the aboveground net primary productivity and seed yield of dominant herbaceous plants[\u003cspan class=\"CitationRef\"\u003e14\u003c/span\u003e]. SG \u003cem\u003eH. erectum\u003c/em\u003e plants allocate substantial resources to constructing competitive vegetative organs in the early growing season. In contrast, AG plants have a life cycle spanning two growing seasons and possess a certain reserve of vegetative tissues by spring; thus, they can allocate a larger proportion of the current year\u0026rsquo;s assimilated resources to reproductive growth earlier. Meanwhile, the increased seed yield induced by elevated precipitation can raise the number of potential seedlings and the extent of seed dispersal, maximize resource utilization, achieve explosive reproduction, replenish the soil seed bank, and serve as a crucial strategy for escaping extreme environmental conditions.\u003c/p\u003e\n\u003cp\u003eIn resource-limited environments, the total biomass and organ-specific biomass of annual plants or SG plants are highly positively correlated with water availability[\u003cspan class=\"CitationRef\"\u003e13\u003c/span\u003e]. Following water addition, biomass accumulation in both SG and AG plants increased significantly, which didn\u0026rsquo;t support our hypothesis. Specifically, elevated precipitation promoted an increase in stem biomass of AG plants, as well as root, stem, leaf, and fruit biomass of SG plants. SG \u003cem\u003eH. erectum\u003c/em\u003e plants are at the early stage of their life cycle, and increased precipitation directly alleviates the water demand for germination and early growth; thus, these plants allocate more resources to roots, stems, leaves, and fruits. In contrast, after overwintering, AG plants have already developed well-established root systems and rosette leaves, when precipitation increases in spring, the enhanced stem biomass provides a guarantee for producing more seeds. Compared with AG plants, the biomass of SG plants is more sensitive to increased precipitation, a result that supports our hypothesis. Phenological stages directly affect plant responses to environmental changes; the earlier the phenology, the more sensitive the plant is to the environment[\u003cspan class=\"CitationRef\"\u003e28\u003c/span\u003e]. Different germination strategies represent adaptations to unstable environments. AG plants exhibit vigorous root growth in spring, enabling them to utilize deep soil water and thus showing low dependence on surface precipitation; accordingly, spring precipitation is insufficient to induce a strong response in their biomass accumulation. In contrast, SG plants place all their \u0026ldquo;bets\u0026rdquo; on the environmental conditions of the current growing season, and their fitness (e.g., biomass) is therefore inevitably more sensitive to fluctuations in key resources (e.g., precipitation) during the season.\u003c/p\u003e\n\u003cp\u003ePlants adjust the biomass allocation between aboveground and belowground parts during growth to balance resource supply and demand[\u003cspan class=\"CitationRef\"\u003e19\u003c/span\u003e]. Following increased precipitation, the proportions of biomass allocated to leaves and stems in both SG and AG \u003cem\u003eH. erectum\u003c/em\u003e plants increased, whereas the proportions of biomass allocated to fruits and roots decreased. According to plant responses to resource allocation, elevated precipitation leads to a decrease in the proportion of root biomass and an increase in the proportion of aboveground biomass, thereby expanding growth space, enhancing competitiveness, and improving productivity[\u003cspan class=\"CitationRef\"\u003e17\u003c/span\u003e]. According to plant responses to resource allocation, elevated precipitation leads to a decrease in the proportion of root biomass and an increase in the proportion of aboveground biomass, thereby expanding growth space, enhancing competitiveness, and improving productivity[\u003cspan class=\"CitationRef\"\u003e17\u003c/span\u003e]. With increased precipitation, AG plants accelerate leaf growth to capture more light, thus gaining a competitive advantage over SG plants. When SG plants are subjected to intense light competition, allocating resources to promote stem elongation and growth represents a crucial survival strategy.\u003c/p\u003e\n\u003cp\u003eThe germination season of plants directly determines seed dormancy of offspring, a critical adaptive trait[\u003cspan class=\"CitationRef\"\u003e11\u003c/span\u003e]. In annual plants, the proportion of seed dormancy varies among seeds produced in different germination seasons, and this variation represents a key adaptation to unpredictable precipitation[\u003cspan class=\"CitationRef\"\u003e20\u003c/span\u003e]. SG \u003cem\u003eH. erectum\u003c/em\u003e plants produce a higher proportion of non-dormant (ND) seeds, whereas AG plants produce a greater number of physically dormant (PY) seeds. When spring precipitation promotes germination, the non-dormant seeds of SG plants can rapidly occupy habitats and achieve rapid population growth. Seed dormancy ensures seed bank accumulation[\u003cspan class=\"CitationRef\"\u003e3\u003c/span\u003e]. Under adverse environmental conditions such as decreased precipitation, some dormant seeds produced by AG plants enter the soil seed bank. When precipitation increases during the growing season, the biomass of both AG and SG plants increases. Simultaneously, the production of physically dormant (PY) and non-dormant (ND) seeds rises respectively, leading to a corresponding increase in the number of seeds in the seed bank and the number of individuals in the population. Therefore, against the backdrop of increased precipitation, the phenomenon of \u003cem\u003eH. erectum\u003c/em\u003e seed germination occurring in both spring and autumn not only mitigates the risk of population extinction under adverse environmental conditions but also enhances the species\u0026apos; competitiveness in plant communities.\u003c/p\u003e"},{"header":"5. Conclusions","content":"\u003cp\u003eThis study systematically investigates the response mechanisms of the life cycle of \u003cem\u003eH. erectum\u003c/em\u003e, an early-spring ephemeral plant in the Changbai Mountain region, to increased precipitation. Increased precipitation can extend the life cycle and seed yield of SG and AG plants, enhance the reproductive capacity of the population to a certain extent, and effectively avoid plant death caused by environmental constraints and interspecific competition. Meanwhile, the biomass accumulation of SG and AG plants increases with increasing precipitation. For SG plants, the proportion of biomass allocated to stems and leaves increases, while the biomass allocation to roots and fruits decreases. These results didn\u0026rsquo;t support the hypothesis that SG plants are more sensitive to water than AG plants, as proposed in our study. Against the backdrop of global climate warming, the biomass and seed yield of SG and AG plants increase, which enhances the competitive advantage of the \u003cem\u003eH. erectum\u003c/em\u003e population under the extreme environmental conditions of early spring. After water treatment, the results of the survival rate and morphological characteristics of SG and AG plants support our hypothesis, as the dry biomass of SG and AG plants increases with the increase in precipitation, and the number of seeds produced also increases. AG plants produce more dormant seeds than SG plants, while SG plants produce more non-dormant seeds, which supports our hypothesis. The impact of increased precipitation induced by climate change may alter the number of non-dormant seeds and the proportion of dormant seeds produced by SG and AG plants. Since SG and AG plants can produce both dormant and non-dormant seeds under increased precipitation, they will continue to germinate, grow, and develop with the increase in summer precipitation.\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.\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\u003eAvailability of data and materials\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll other data generated or analyzed during this study are included in this published article.\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\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study received funding from the University-Enterprise Cooperation Project (25JBH027L254) and University-Enterprise Cooperation Project (25JBH027L055).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors\u0026apos; contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eS.L.Y.: Writing-original draft; Writing-review \u0026amp; editing; Funding acquisition\u003c/p\u003e\n\u003cp\u003eR.R.C.: Data curation; Software; Formal analysis\u003c/p\u003e\n\u003cp\u003eX.Y.Y.: Supervision; Visualization\u003c/p\u003e\n\u003cp\u003eY.T.H.: Project administration\u003c/p\u003e\n\u003cp\u003eY.J.: Methodology\u003c/p\u003e\n\u003cp\u003eR.J.L.: Conceptualization\u003c/p\u003e\n\u003cp\u003eD.X.J.: Conceptualization\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n \u003cli\u003eAkiyama R., Agren J. Conflicting selection on the timing of germination in a natural population of Arabidopsis thaliana. J. Evol. Biol. 2014; 27(1): 193-199.\u003c/li\u003e\n \u003cli\u003eAugspurger C. K. Reconstructing patterns of temperature, phenology, and frost damage over 124 years: spring damage risk is increasing. Ecology. 2013; 94(1): 41-50.\u003c/li\u003e\n \u003cli\u003eBaskin C. C., Baskin J. M. Seeds: ecology, biogeography, and, evolution of dormancy and germination. Academic press; 2000.\u003c/li\u003e\n \u003cli\u003eCend\u0026aacute;n C., Sampedro L., Zas R. The maternal environment determines the timing of germination in Pinus pinaster. Environ. Exp. Bot. 2013; 94: 66-72.\u003c/li\u003e\n \u003cli\u003eChen H. S., Nie Y. P., Wang K. L. Research progress on spatio-temporal heterogeneity of water and plant adaptation mechanisms in karst mountain areas. Acta Ecol. Sinica. 2013; 33(2): 317-326 (in chinese with English abstract).\u003c/li\u003e\n \u003cli\u003eChilds D. Z., Rees M., Rose K. E., et al. Evolution of size\u0026ndash;dependent flowering in a variable environment: construction and analysis of a stochastic integral projection model. Proceedings of the Royal Society of London. Series B: Biological Sciences. 2004; 271(1537): 425-434.\u003c/li\u003e\n \u003cli\u003eCui J. Y., Yan J. Y., Gao Y., et al. Life history characteristics of double-season germinating plants of ephemeral \u003cem\u003eDescurainia sophia\u003c/em\u003e. Pratacultural Science. 2025; 42(2): 267-277 (in chinese with English abstract).\u003c/li\u003e\n \u003cli\u003eCui J. Y. Growth dynamics and resource allocation strategies of spring-germinating and autumn-germinating plants of ephemeral \u003cem\u003eDescurainia sophia\u003c/em\u003e. Xinjiang Agricultural University. 2024 (in chinese with English abstract).\u003c/li\u003e\n \u003cli\u003eDonat M. G., Lowry A. L., Alexander L. V., et al. More extreme precipitation in the world\u0026rsquo;s dry and wet regions. Nat. Clim. Change. 2016; 6(5): 508-513.\u003c/li\u003e\n \u003cli\u003eFlannigan M. D., Wotton B. M., Marshall G. A., et al. Fuel moisture sensitivity to temperature and precipitation: climate change implications. Clim. Change. 2016; 134(1): 59-71.\u003c/li\u003e\n \u003cli\u003eGalloway L. F., Etterson J. R. Transgenerational plasticity is adaptive in the wild. Science, 2007; 318(5853): 1134-1136.\u003c/li\u003e\n \u003cli\u003eHusen A., Iqbal M., Aref I. M. Plant growth and foliar characteristics of faba bean (\u003cem\u003eVicia faba\u003c/em\u003e L.) as affected by indole-acetic acid under water-sufficient and water-deficient conditions. J. Environ. Biol. 2017; 38(2): 179-185.\u003c/li\u003e\n \u003cli\u003eHuxman T. E., Smith M. D., Fay P. A., et al. Convergence across biomes to a common rain-use efficiency. Nature. 2004; 429(6992): 651-654.\u003c/li\u003e\n \u003cli\u003eKnapp A. K., Fay P. A., Blair J. M., et al. Rainfall variability, carbon cycling, and plant species diversity in a mesic grassland. Science. 2002; 298(5601): 2202-2205.\u003c/li\u003e\n \u003cli\u003eKreyling J., et al. Water availability and drought responses of tree seedlings at the alpine treeline.\u0026nbsp;J. Ecol. 2012; 100(5): 1231-1240.\u003c/li\u003e\n \u003cli\u003eLu\u0026nbsp;J. J., Tan\u0026nbsp;D. Y., Baskin\u0026nbsp;J. M., Baskin\u0026nbsp;C. C. Germination season and watering regime, but not seed morph, affect life history traits in a cold desert diaspore-heteromorphic annual. Plos ONE. 2014; 9:e102018.\u003c/li\u003e\n \u003cli\u003eParent C., Capelli N., Dat J. F. Soil waterlogging and root hypoxia in spring reduce growth and survival of black spruce seedlings. \u0026nbsp;Plant Soil. 2015; 394(1-2), 109-122.\u003c/li\u003e\n \u003cli\u003ePoorter H., Nagel O. The role of biomass allocation in the growth response of plants to different levels of light, CO\u003csup\u003e2\u003c/sup\u003e, nutrients and water: a quantitative review. Aust. J. Plant Physiol. 2000; 27(6): 595-607.\u003c/li\u003e\n \u003cli\u003eSchenk H. J., Jackson R. B. Rooting depths, lateral root spreads and below-ground above-ground allometries of plants in water-limited ecosystems. J. Ecol. 2002; 90(3): 480-494.\u003c/li\u003e\n \u003cli\u003eShipley B., Meziane D. The balanced‐growth hypothesis and the allometry of leaf and root biomass allocation. Funct. Ecol. 2002; 16(3): 326-331.\u003c/li\u003e\n \u003cli\u003eVenable D. L. Bet hedging in a guild of desert annuals. Ecology, 2007; 88(5): 1086-1090.\u003c/li\u003e\n \u003cli\u003eWang C. T., Wang Q. J., Shen Z. X., et al. A preliminary study of the effect of simulated precipitation on an apline Kobresia humilis meadow.\u0026nbsp;Acta Pratacult. Sinica. 2003; 12(2): 19-25.\u003c/li\u003e\n \u003cli\u003eWei J., Chen Q. Research progress on the effects of precipitation changes on grassland shrubification. Chin. Bull. Life Sci. 2025; 32(1): 727-735 (in chinese with English abstract).\u003c/li\u003e\n \u003cli\u003eYang S. L., Zhou Y. P., Shi X. Flowering phenology and reproductive characteristics of the ephemeral plant\u0026nbsp;\u003cem\u003eHypecoum erectum\u003c/em\u003e L. Acta Bot. Boreali-Occident. Sinica. 2016; 36(9): 1855-1863.\u003c/li\u003e\n \u003cli\u003eYang X. Y., Ma L., Zhang Z. H., et al. Relationship between growth and development characteristics of alpine meadow plant communities and climatic factors. Acta Ecol. Sinica. 2021; 41(9): 12-24 (in chinese with English abstract).\u003c/li\u003e\n \u003cli\u003eZhang H., Wang X. P, Zhang Y. F., et al. Responses of plant growth with different life forms to precipitation changes in arid desert areas. Chin. J. Ecol. 2015; 34(7): 1847-1853 (in chinese with English abstract).\u003c/li\u003e\n \u003cli\u003eZhang L. Y., Chen C. D. On the general characteristics of plant diversity in the Gurbantunggut Desert. Acta Ecol. Sinica. 2002; 22(11): 1923-1932 (in chinese with English abstract).\u003c/li\u003e\n \u003cli\u003eZhang L., Zhang L. W., Liu H. L., et al. Effects of increased precipitation on the growth of two ephemeral plants in the Gurbantunggut Desert. Chin. J. Appl. Ecol.2020; 31(1): 9-16 (in chinese with English abstract).\u003c/li\u003e\n \u003cli\u003eZohner C. M., Renner S. S. Common mid-season period of temperature sensitivity across woody species. New Phytol. 2019; 222(1): 176-183.\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":"Climate change, Ephemeral plant life histery, Hypecoum erectum L., Increased precipictation","lastPublishedDoi":"10.21203/rs.3.rs-8417446/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8417446/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003ePrecipitation change is one of the research hotspots in global climate change nowadays and a major environmental factor affecting plant growth and development. In this study, we mainly analyzed the life-history traits of spring-and autumn-germinated seeds of \u003cem\u003eH. erectum\u003c/em\u003e L. By conducting a field control experiment with three precipitation regimes (natural precipitation, 30% water addition, and 50% water addition), we comparatively investigated the phenology, seedling survival rate, plant size, seed yield, and biomass accumulation and allocation of SG and AG plants. The results showed that increased precipitation delayed the phenology of both SG and AG plants, and significantly improved seedling survival rate, with the survival rate of AG plants being remarkably lower than that of SG conspecifics. In addition, increased precipitation significantly increased the leaf number, branch number, branch length and plant height of SG plants, whereas it remarkably decreased the leaf number and root length of AG plants. After water addition, the seed production of both SG and AG plants increased significantly, with the seed yield of AG plants being remarkably higher than that of SG ones. With the increase in precipitation, the proportion of dormant seeds of SG plants increased significantly, whereas the corresponding proportion of AG plants decreased remarkably. The effects of increased precipitation on the life history of \u003cem\u003eH. erectum\u003c/em\u003e L. varied with germination seasons, which is of great significance for predicting its population dynamics under climate change.\u003c/p\u003e","manuscriptTitle":"Effects of increased precipitation and on the life history of spring- and autumn-germinated plants of the annual Hypecoum erectum L.","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-12-30 07:15:19","doi":"10.21203/rs.3.rs-8417446/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":"27cf753c-ea81-4a5e-ba98-b05b06461b82","owner":[],"postedDate":"December 30th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2026-01-28T05:09:57+00:00","versionOfRecord":[],"versionCreatedAt":"2025-12-30 07:15:19","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8417446","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8417446","identity":"rs-8417446","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}