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Seed‐based restoration is dependent on seed germination, and poor germination can cause restoration failure. Many restoration failures can be attributed to a lack of knowledge of germination characteristics, species‐specific seed dormancy, or the effects of widely used herbicides on germination. White penstemon (Penstemon albidus) and Waxleaf penstemon (P. nitidus) are native to the Northern Great Plains region of North America, and increased germination of these species would contribute to improved restoration in the region. We performed two concurrent experiments to determine: (1) the germination requirements and dormancy class of these species; and (2) the effects of herbicides on germination. To determine germination requirements, we applied pretreatments (scarification, smoke, and KNO3) and three durations (2, 4, and 8 weeks) of cold and warm stratification. To test the effects of herbicides on germination, three commonly used herbicides (atrazine, trifluralin, and 2,4‐D) were applied at six concentrations (100, 50, 10, 1, 0.1, and 0% of the recommended field application rate). Germination characteristics indicate both species express physiological dormancy. Physiological dormancy denotes an embryo with low growth potential that is unable to overcome mechanical constraints but can be alleviated with proper temperature cues. Both species required cold stratification, with P. nitidus needing a longer period (8 weeks) than P. albidus (4 weeks). Final germination percentage of P. albidus decreased with higher doses of 2,4‐D but was not affected by atrazine or trifluralin. These experiments help to create protocol for the use of our study species, as well as other species, in restoration plantings. [ABSTRACT FROM AUTHOR]

Understanding the modulating effect of environmental conditions on the germination of seeds constituting a persistent soil seed bank has both theoretical and practical merits. I studied the role of precipitation in the germination of seeds of the imperiled geophyte Iris atrofusca , which exhibits strong seed dormancy and intermittant germination over years. I wanted to know how a single significant rain event in one of the first several seasons after seed maturation and dispersal can affect seed germination and seedling growth in I. atrofusca. This is important because knowing the amount and time of such a rainfall event, one can imitate it by a single watering applied to an artificial soil seed bank, thus initiating or substantially increasing seed germination and improving seedling growth and therefore survival. Overall, the results imply that the most efficient in terms of both seed germination and seedling survival is supplementary irrigation equivalent to 40 mm rainfall applied as a single rain event to the artificial soil seed bank early in the first and second season, plus watering equivalent to 20–40 mm in the months when the amount of precipitation is low (below 20 mm) not only in the first and second, but also in subsequent seasons. [ABSTRACT FROM AUTHOR]

Ornithopus sativus Brot. (French serradella) is a forage legume that is well adapted to acidic coarse textured soils (sands) which are characterized by poor nutrition and an inability to retain water. During the process of domestication of O. sativus, there was an unintentional loss of seed physical dormancy (PY) thus compromising its self‐regeneration after a cropping interval. Through mass screening of seed, we identified for the first time that heritable sources of PY exist in three populations of O. sativus. This rare genetic material was then incorporated into suitable genetic backgrounds of differing maturity through targeted hybridization. We demonstrated that the heritability of PY was dominant in the population of 97ZAF5sat but inconsistently recessive in the population of cv. Emena. Flowering time was variable in each source population, with a large variation in time to emergence of first flowers (95–175 days). Selection for early flowering maturity was heritable and stable. F6 generations selected for PY in different maturity classes were then evaluated in situ to establish whether PY would allow a proportion of seeds to survive in the soil through consecutive seasons exposed to a Mediterranean climate. The breeding lines FHS3, 7 and 23 remained dormant, thus viable, in the soil for up to 3 years, indicating the likelihood that O. sativus with PY could survive and persist in a ley farming system. The de‐domestication program in O. sativus has resulted in commercially successful cultivars (most recently cv. Fran2o) suited to sustainable dryland agriculture in a Mediterranean climate. [ABSTRACT FROM AUTHOR]

Soil seedbanks are particularly important for the resiliency of species living in habitats threatened by climate change, such as alpine meadows. We investigated the germination rate and seedbank potential for the endemic species Dianthus pavonius, a carnation native to the Maritime Alps that is used as model system for disease in natural populations due to its frequent infections by a sterilizing anther-smut pathogen. We aimed to ascertain whether this species can create a persistent reserve of viable seeds in the soil which could impact coevolutionary dynamics. Over three years, we collected data from seeds sown in natural soil and analyzed their germination and viability. We found that D. pavonius seeds are not physiologically dormant and they are able to create a persistent soil seed bank that can store seeds in the soil for up to three years, but lower than the estimated plant lifespan. We conclude that while the seedbank may provide some demographic stability to the host population, its short duration is unlikely to strongly affect the host's ability to respond to selection from disease. Our findings have implications for the conservation of this alpine species and for understanding the evolutionary dynamics between the host and its pathogen. [ABSTRACT FROM AUTHOR]

Rheum pumilum stands as both a quintessential alpine plant and a significant traditional Chinese and Tibetan medicinal herb. Unraveling the molecular intricacies of seed germination in Rh. pumilum not only unveils the genetic foundations of plant seed germination strategies in high-altitude environments but also offers insights for cultivating Rh. pumilum medicinal materials. Employing transcriptome sequencing and the Weighted Gene Co-expression Network Analysis, this study delved into the shifts in gene expression levels across various stages of seed germination in Rh. pumilum. The process of seed germination in Rh. pumilum entails a cascade of complex physiological events. Six hormones (ABA, IAA, ETH, GA, BR, CK) emerged as pivotal players in seeds breaking in shells and the facilitation of rapid seed germination in Rh. pumilum. Fourteen transcription factor families (LOB, GRAS, B3, bHLH, bZIP, EIL, MYB, MYB related, NAC, TCP, WRKY, HSF, PLATZ, and SBP) along with four key genes (E2.4.1.13, EIN3, BZR, and BIN2) were identified that may be associated with both biotic and abiotic environmental stress. The ETR, ACACA and ATPeV0C genes were linked with energy accumulation during the initial stages of seed germination, CYP707A may play an important role in breaking seed dormancy, while the BRI1 gene may be correlated with swift seed germination. Additionally, several unidentified genes were recognized to play key roles in seed germination of Rh. pumilum, warranting further investigation. Moreover, Rh. pumilum demonstrates full activation of crucial physiological functions such as energy metabolism, signal transduction, and responses to biological and abiotic stresses during the seed breaking in shells. This study provides molecular evidence elucidating the swift seed germination strategies adopted by alpine plants to thrive in high-altitude environments. Furthermore, it serves as a foundational reference for enhancing seed germination rates and breeding practices to promote the sustainable development of Rh. pumilum medicinal materials. [ABSTRACT FROM AUTHOR]

High-quality seeds provide valuable nutrients to human society and ensure successful seedling establishment. During maturation, seeds accumulate storage compounds that are required to sustain seedling growth during germination. This review focuses on the epigenetic repression of the embryonic and seed maturation programs in seedlings. We begin with an extensive overview of mutants affecting these processes, illustrating the roles of core proteins and accessory components in the epigenetic machinery by comparing mutants at both phenotypic and molecular levels. We highlight how omics assays help uncover target-specific functional specialization and coordination among various epigenetic mechanisms. Furthermore, we provide an in-depth discussion on the Seed dormancy 4 (Sdr4) transcriptional corepressor family, comparing and contrasting their regulation of seed germination in the dicotyledonous species Arabidopsis and two monocotyledonous crops, rice and wheat. Finally, we compare the similarities in the activation and repression of the embryonic and seed maturation programs through a shared set of cis-regulatory elements and discuss the challenges in applying knowledge largely gained in model species to crops. [ABSTRACT FROM AUTHOR]

Flixweed (Descurainia sophia) is a weed that seriously affects wheat fields in China. Over the past 20 years, it has evolved resistance to the herbicide tribenuron-methyl. In the present study, a resistant D. sophia population with a Pro-197-Thr mutation of acetolactate synthetase (ALS) was found to have a resistance index of 457.37 for tribenuron-methyl. Under the same growth conditions, the seeds of resistant (R) and susceptible (S) populations exhibited similar vitality but the germination rates of R seeds were higher than those of S seeds. This result demonstrated that seed dormancy periods were shorter in the R seeds. RNA-Seq transcriptome analysis was then used to choose candidate genes that could regulate seed dormancy pathways in the R population. A total of 504,976,046 clean reads were selected from nine RNA-Seq libraries and assembled into 79,729 unigenes. Among these, 33,476 unigenes were assigned to 51 GO subgroups, and 26,117 unigenes were assigned to 20 KEGG secondary metabolic pathways. Next, 2473 differentially expressed genes (DEGs) were divided into three groups, as follows: G-24 h (germinating seeds) vs. D (dormant seeds); G-48 h (germinated seeds) vs. D; and G-48 h vs. G-24 h. From these 2473 DEGs, 8 were selected as candidate dormancy unigenes for the R population if their expression levels continuously decreased during the seed germination progress and their functional annotations were related to plant seed dormancy. One candidate unigene was annotated as CYP707A2; two unigenes were annotated as the transcription factors TGA4 and TGA2; one unigene was annotated as the cystathionine beta-synthase gene; and four unigenes could not be annotated as any gene listed in the six public databases. However, qRT-PCR-validated results showed that, during the germination of R seeds, the expression of the three candidate unigenes first decreased and then increased, indicating that they may have other growth-regulating functions in R populations. In brief, the dormancy function of the eight candidate dormancy unigenes needs to be further studied. [ABSTRACT FROM AUTHOR]

Paeonia peregrina Mill. is a protected, herbaceous species native to Southeastern Europe and Turkey. Due to its vulnerability, it has to be protected both in its natural habitats and through cultivation. Peonies are known to have a low potential for natural regeneration due to their seed dormancy, low germination rate, and long germination period. In this study, treatments with gibberellic acid (GA3 150, 200, 250, 300, and 350 mg L−1 GA3) and warm (at 20/16 °C day/night regime) and cold stratification (at 4 °C) were used to accelerate dormancy release and increase the germination rate. The seeds of P. peregrina from four natural habitats in Serbia and the Institute's collection were collected and analyzed. They showed an underdeveloped embryo that needs to grow inside the seed before it can germinate. The application of GA3 accelerated each stage of germination (seed coat rapturing, hypocotyl dormancy release, and epicotyl dormancy release) for approximately 10 days compared to the control. It was also found that two-day imbibition with 200 mg L−1 GA3 significantly accelerated and equalized germination. Higher GA3 concentrations had a more pronounced impact on each stage but also resulted in greater seed infection after the seed coat rupture, elongated and weak seedlings, while lower concentrations did not result in obtaining uniform seedlings. There were no significant differences observed between localities. Restoring P. peregrina through seeds and nursery-produced plants is crucial for conserving the genetic diversity of the tested species. [ABSTRACT FROM AUTHOR]

Purpose: Epimedium brevicornu Maxim. is a perennial persistent C3 plant of the genus Epimedium Linn. in the family Berberaceae that exhibits severe physiological and morphological seed dormancy.We placed mature E. brevicornu seeds under nine stratification treatment conditions and explored the mechanisms of influence by combining seed embryo growth status assessment with related metabolic pathways and gene co-expression analysis. Results: We identified 3.9 °C as the optimum cold-stratification temperature of E. brevicornu seeds via a chilling unit (CU) model. The best treatment was variable-temperature stratification (10/20 °C, 12/12 h) for 4 months followed by low-temperature stratification (4 °C) for 3 months (4-3). A total of 63801 differentially expressed genes were annotated to 2587 transcription factors (TFs) in 17 clusters in nine treatments (0-0, 0-3, 1-3, 2-3, 3-3, 4-3, 4-2, 4-1, 4-0). Genes specifically highly expressed in the dormancy release treatment group were significantly enriched in embryo development ending in seed dormancy and fatty acid degradation, indicating the importance of these two processes. Coexpression analysis implied that the TF GRF had the most reciprocal relationships with genes, and multiple interactions centred on zf-HD and YABBY as well as on MYB, GRF, and TCP were observed. Conclusion: In this study, analyses of plant hormone signal pathways and fatty acid degradation pathways revealed changes in key genes during the dormancy release of E. brevicornu seeds, providing evidence for the filtering of E. brevicornu seed dormancy-related genes. [ABSTRACT FROM AUTHOR]

Preharvest sprouting (PHS) is a serious problem in wheat (Triticum aestivum L.) production areas with rainy harvest conditions. To explore the genetic control of PHS resistance, a population of 166 recombinant inbred lines from a cross between SHA3/CBRD and Naxos was evaluated in a total of eight field trials in Norway and China. PHS resistance was evaluated with both germination index (GI) and falling number (FN). A total of 15 PHS‐related quantitative trait loci (QTLs) were detected at chromosome arms 1RS, 2DL, 3BL, 4AL, 4BS, and 7BL. At 2DL and 3BL, QTLs for both GI and FN were detected in proximity to each other with PHS resistance from SHA3/CBRD, indicating a common genetic control of the two traits at these loci. At 4AL, a significant QTL for GI was detected with seed dormancy contributed by Naxos. Moreover, the Rht‐B1b dwarfing allele contributed by SHA3/CBRD showed a positive association with FN. On the other hand, QFN.nmbu‐1RS, carried by the 1BL.1RS translocation in SHA3/CBRD showed consistent negative effects on FN across all field trials where FN was measured. However, it did not have any notable effect on GI. The negative effect of QFN.nmbu‐1RS on FN was validated on a set of 113 wheat cultivars and breeding lines, where lines carrying the 1BL.1RS translocation showed significantly lower FN in 12 out of 14 independent field trials. The QTL and associated markers identified in this study will aid the breeding of more PHS‐resistant wheat cultivars. [ABSTRACT FROM AUTHOR]

Solanum torvum, a wild relative of eggplant in the Solanaceae family, is widely used as a rootstock to prevent various soil-borne diseases. Despite this valued trait, S. torvum seeds exhibit strong seed dormancy, resulting in low-frequency germination and uneven emergence rates during agricultural production. In this study, exogenous gibberellin (GA) was applied to induce the germination of seeds, thereby enabling the application of transcriptome analysis to explore the effects of exogenous GA on germination. A total of 9723 genes were identified to be involved in GA-induced germination of S. torvum seeds. These GA-associated genes were enriched in amino sugar and nucleotide sugar metabolism, glycolysis, the citrate cycle, pyruvate metabolism, hormone biosynthesis, and signaling transduction. Further analysis of these genes reveals that exogenous GA impaired the endogenous biosynthesis of GA. Analysis of the 285 key genes influenced by GA, auxin, abscisic acid (ABA), and other hormones suggests mutual crosstalk in the signaling of various hormones, enabling the joint regulation of the germination of S. torvum seeds. Additionally, a total of 440 genes encoding transcription factors were identified to be responsible for transcriptional reprogramming during GA-induced seed germination, and putative candidate genes responsible for S. torvum seed dormancy and germination, including ABI5, DOG1, DRM1, LEC1, and PIF, were significantly down-regulated in germinated S. torvum seeds. These findings provide the first insights into transcriptome regulation during GA-induced germination of S. torvum seeds. [ABSTRACT FROM AUTHOR]

In many regions, the climate is changing faster during winter than during the other seasons, and a loss of snow cover combined with increased temperature variability can expose overwintering organisms to harmful conditions. Understanding how species respond to these changes during critical developmental times, such as seed germination, helps us assess the ecological implications of winter climate change. To address this concern, we measured the breaking of seed dormancy and cold tolerance of temperate grassland species in the lab and field. In the lab, we ran germination trials testing the tolerance of 17 species to an extreme cold event. In the field, we deployed seeds of two species within a snow manipulation experiment at three locations and measured germination success biweekly from seeds subjected to ambient and reduced snow cover from winter into spring. From lab trials, cold tolerance varied among species, with seed germination decreasing <10%–100% following extreme cold events. Cold tolerance was related to seed traits, specifically less round seeds, seeds that required cold stratification, and seeds that mature later in the season tended to be more impacted by extreme cold temperatures. This variation in seed cold tolerance may contribute to altered community composition with continued winter climate change. In the field, germination increased through late winter, coinciding with the accumulation of days where temperatures were favorable for cold stratification. Through spring, germination success decreased as warm temperatures accumulated. Collectively, species‐specific seed cold tolerances and mortality rates may contribute to compositional changes in grasslands under continued winter climate change. [ABSTRACT FROM AUTHOR]

The success of plant growth and development in dryland restoration relies on seed germination, seedling development, and establishment. The lack of rainfall and extreme temperature variations in arid regions impede germination and seedling establishment, necessitating new approaches and techniques. The present review summarizes the vital role of seed priming techniques for the sustainable restoration of drylands through their effects on enhancing seed germination, seedling growth and development, plants' nutrient use efficiency, soil fertility, essential enzymes, microbial community, and stress adaptation ability, helping to alleviate the effects of abiotic stresses on plants. The importance of seed priming is discussed in both agricultural and ecological restoration contexts. Priming maximizes crop yields, reduces crop failure, and promotes eco‐friendly farming practices. In ecological restoration, seed priming enhances plant establishment and survival, contributing significantly to the restoration of native vegetation and wildlife habitats. The review categorizes seed priming techniques into six subcategories, highlighting their unique advantages for optimizing restoration efforts. The review highlights the underlying mechanisms of seed priming techniques to improve seed germination and plant development in dryland regions, particularly under salinity and drought constraints. While seed priming has proven effective, it also faces several limitations, such as cost, seed longevity, and environmental concerns. Investigating environmentally friendly priming methods and understanding the prolonged effects of priming on seed viability and the environment is crucial. Further research is needed to find cost‐effective, eco‐friendly seed priming methods, and to explore the genetic and molecular bases of stress tolerance in various plant species across diverse environments. [ABSTRACT FROM AUTHOR]

The use of native plants for arid land restoration requires the application of pre‐germination treatments to alleviate seed dormancy mechanisms. As it is known, scarification allows several valuable species to overcome the primary forms of dormancy. However, supplying large quantities of scarified seeds at a low cost represents a significant challenge. In this context, our objective was to evaluate locally constructed machines accessible to people of degraded lands in a state of poverty. The effectiveness was evaluated by comparing two native shrubs from South American arid lands, Larrea divaricata and L. cuneifolia. Four treatments were applied: control (T0), mechanical scarification with a hand drill equipped with sandpaper on its head (T1), and mechanical scarification for 15 seconds (T2) and 30 seconds (T3) with a self‐constructed machine, capable of regulating pressure and speed. For both species, the germination probability was higher with T2 (0.82 ± 0.02) compared to T0 (0.28 ± 0.03) and T1 (0.65 ± 0.03). T3 presented intermediate values (0.75 ± 0.03) but did not differ significantly from T1 and T2. Our results show the effectiveness of a locally constructed seed scarification tool to upscale seed‐based restoration in arid lands. [ABSTRACT FROM AUTHOR]

Background and Aims Chinese pistachio (Pistacia chinensis), an important horticultural plant species, holds great ornamental value with beautiful leaves and fruits. Seedling propagation of this tree species is restricted by its erratic seed germination; however, the germination mechanism is ambiguous. The aim of this study was to determine the germination mechanism from a novel perspective based on the multi-omics data. Methods The multi-omics technique combined with hormone content measurement was applied to seed germination of Chinese pistachio. Key Results Due to its great accumulation during seed germination, catechin stood out from the identified metabolites in a broadly targeted metabolomic analysis. Exogenous catechin at 10 mg L−1 significantly improved the germination of Chinese pistachio seeds. An interesting result of hormone analysis was that the improving effect of catechin could be attributed to an increase in gibberellic acid 3 (GA3) content rather than a decrease in abscisic acid (ABA) content before germination. Treatments with paclobutrazol (PAC, a GA biosynthesis inhibitor) and PAC + catechin also showed that the promoting effect of catechin on seed germination depends on GA biosynthesis. Transcriptome analysis and qRT‒PCR further revealed that catechin induced the expression of PcGA20ox5 to activate GA biosynthesis. Several transcription factors were induced by catechin and GA treatments, such as TCP, bZIP and C3H, which may play an important regulatory role in GA biosynthesis in a catechin-mediated way. Conclusions Catechin promotes seed germination via GA biosynthesis in Chinese pistachios. This study proposes a novel mechanism by which catechin promotes seed germination via the GA pathway, which provides new insight into a comprehensive understanding of seed dormancy and germination. [ABSTRACT FROM AUTHOR]

Background: Understanding the reproductive biology of weeds is crucial for managing them effectively. Diplachne fusca (Poaceae) is a widely distributed weed species that poses significant challenges to agricultural productivity. Nevertheless, it remains unclear how the soil seed bank of D. fusca responds to environmental shifts, and whether a dormancy cycle is present in this species. Methods: We investigated how seed dormancy in D. fusca is broken and how it responds to natural environmental changes. The impact of incubation temperature, light exposure, cold stratification at 4 °C, and gibberellic acid (GA3) on seed germination/dormancy-break was investigated, along with assessing seasonal changes in germinability through monthly excavation and laboratory incubation of buried seeds over 2 years. Results: Results indicated that newly ripened seeds of D. fusca were dormant, with germination facilitated by GA3, cold stratification, and after-ripening at ambient room conditions. Exposure to darkness inhibited germination. Seasonal patterns of germination were observed, with peak germination occurring in cooler months and a marked decline during the hot summer months. After 2 years of being buried, approximately 40% of the seeds remained viable. Conclusion: In summary, seeds of D. fusca exhibit non-deep physiological dormancy and maintain a persistent soil seed bank. Seeds buried in the soil undergo a yearly dormancy/non-dormancy cycle. This dormancy cycle prevents seed germination and seedling emergence in autumn, which boosts the survival of seedlings in less favorable seasons, yet it also makes it more challenging to eradicate this weed. [ABSTRACT FROM AUTHOR]

Seed physical dormancy (hard-seededness) is an interesting ecological phenomenon and important agronomic trait. The loss of seed coat impermeability/hard-seededness is a key target trait during the domestication of leguminous crops which allows seeds to germinate rapidly and uniformly. In this study, we examined the mutation of quantitative trait locus (QTL) genes, GmHs1-1 and GmqHS1, in 18 wild soybean (G. soja) and 23 cultivated soybean (G. max) accessions. The sequencing results indicate that a G-to-T substitution in GmqHS1 and a C-to-T substitution in GmHs1-1 occurred in all 23 cultivated soybean accessions but not in any of the 18 wild soybean accessions. The mutations in the two genes led to increased seed coat permeability in cultivated soybean. Therefore, we provide evidence that two genes, GmHs1-1 and GmqHS1, simultaneously contribute to the domestication of hard-seededness in soybeans. This finding is of great significance for genetic analysis and improved utilization of the soybean hard-seededness trait. [ABSTRACT FROM AUTHOR]

Abscisic acid (ABA) is a well-known phytohormone that initiates seed dormancy. This is the first study elucidating the variability and relationship in the accumulation of phenolics, melatonin, and momilactones A (MA) and B (MB) during a rice (Oryza sativa L. var. Koshihikari, Akisakari, and Akiroman) seed dormancy process treated by ABA with concentrations of 0 (control), 10, 50, and 100 µM over 8 days. Accordingly, increased concentrations of ABA resulted in an extended dormancy period of rice seeds, along with reducing fresh weight while maintaining stable dry weight in all varieties. ABA treatment elevated total phenolic (TPC) and flavonoid (TFC) contents. Particularly, quantities of ferulic and cinnamic acids were enhanced, in line with the promoted antioxidant capacities of ABA-treated rice seeds. Momilactone contents were increased (3.8% to 32.6% for MA and 16.3% to 31.3% for MB) during the extension of rice seed dormancy regulated by ABA. Notably, the accumulation tendency of MA and MB under ABA effects was consistent with that of melatonin, a phytohormone associated with seed dormancy prolongation. The finding implies that MA and MB may play a role alongside melatonin in signaling the extended dormancy of rice seeds through the ABA pathway. Future research should delve into the molecular mechanisms underlying these observations. [ABSTRACT FROM AUTHOR]

Tulips are among the most famous plants that are used mainly as ornamental cut flowers. Although widely cultivated, they are mainly reproduced asexually, and knowledge of their sexual reproduction is imperfect, especially in regard to botanical tulips. The aim of the present study was to investigate the temperature effect on seed germination of the Near Threatened wild-growing Greek subendemic plant Tulipa saxatilis (Liliaceae) and to define its seed dormancy type. Seed germination was facilitated by bioclimatic profiling generated with R software (version 4.3.3) connecting its natural distribution points with open access precipitation and temperature data, and it was assessed upon incubation in controlled growth chambers at five constant temperatures (5, 10, 15, 20 and 25 °C) under a 12:12 light–dark photoperiod. The seeds were dependent on temperature for germination and germinated only within a very narrow range of relatively low temperatures (5–15 °C) and optimally at 10 °C (93%), corresponding to natural winter temperatures and precipitation profiles. Increase in the incubation temperature at 20 and 25 °C resulted in no germination. The treatment of seeds with gibberellic acid (GA3) at two different concentrations (500, 1000 mg·L−1) did not widen the temperature range for seed germination. The seeds of T. saxatilis initially presented an underdeveloped embryo, and significant embryo development was detected only at low temperatures (10 and 15 °C) with almost triple embryo length after one month, thus confirming the existence of complex morphophysiological seed dormancy. Moreover, germinated seeds (with and without GA3) were planted in small-sized pots under greenhouse conditions, and the growth of bulblets was investigated in response to the application of commercially available chemical fertilizers, an integrated nutrient management scheme, and a biostimulant. The fertilization schemes affected the weight and length of the produced bulblets, whereas initial seed treatment with GA3 negatively affected the growth (weight, length, and width) of the produced bulblets. [ABSTRACT FROM AUTHOR]

Podophyllum hexandrum Royle, also known as Podophyllum emodi Wall, holds significant ecological, ornamental, and medicinal values. However, it has become endangered due to overexploitation, prolonged seed dormancy, slow natural regeneration, and climate change. This study developed an efficient in vitro protocol for callogenesis and micropropagation of P. hexandrum to conserve germplasm in in vitro conditions. Callus formation from various plant parts, including the leaf, stem, rhizome, radicle, and cotyledon, was induced using Murashige and Skoog (MS) medium supplemented with different plant growth regulators. The combination of benzyladenine at 1 mg L−1 and 4-dichlorophenoxy acetic acid at 3 mg L−1 was optimal for biomass production, yielding 215.88 ± 0.31 mg, with growth per gram at 8.32 ± 0.32 and a growth rate of 13.62 ± 0.25 mg/day on MS medium. For shoot proliferation, benzyladenine (3.5 mg L−1) and naphthalene acetic acid (0.5 mg L−1) combined with activated charcoal showed the highest shoot induction percentage per explant. For shoot regeneration from calluses, 6-benzylaminopurine (0.5 mg L−1) and thidiazuron (2 mg L−1) were most effective, producing superior shoot length, number of regenerations, and regeneration percentage. Root induction was successful with α-naphthalene acetic acid supplementation (0.5 to 1.5 mg L−1) in MS medium, resulting in the highest number per explant (4.08 ± 0.08), length (5.45 ± 0.15 cm), and rooting rate (87.00 ± 1.66%) of roots in plantlets. Subculturing for callus culture was performed every 28 days for up to four subcultures to prevent nutrient depletion and toxic metabolite accumulation, ensuring tissue health and viability. Continuous subculturing of callus on MS medium maintained healthy P. hexandrum germplasm in vitro. Overall, this micropropagation protocol provides a rapid system for conserving P. hexandrum germplasm. [ABSTRACT FROM AUTHOR]

Seeds of winter strawberry (Rubus buergeri Miq.) germinate at a low rate over an extended period due to their hard coat and deep dormancy. This study compared the effects of different physicochemical treatments on the germination rate and duration of the germination period of winter strawberry seeds. Seeds were treated by sandpaper scarification, sulfuric acid (H2SO4) scarification, and gibberellic acid (GA3). Of these physicochemical treatments, sandpaper scarification produced the greatest improvement to the germination rate and shortening of the germination period. Treatment with GA3 also produced positive effects, albeit to a lesser level. By contrast, sulfuric acid scarification decreased the germination rate relative to the control group. Although GA3 treatment had positive effects on true leaf formation and subsequent growth of seedlings, sandpaper scarification was the most effective method of inducing true leaf formation within a short period and, subsequently, for ensuring normal growth. Sandpaper scarification of seed resulted in > 90% germination, representing an approximately 80% improvement compared with the control group by week 6. Moreover, true leaves emerged in ~ 70% of seedlings within 6 weeks. Sandpaper scarification was thus a very effective seed treatment, not only for improving the germination rate and shortening the germination period of winter strawberry seeds but also for producing healthy seedlings. [ABSTRACT FROM AUTHOR]

Preharvest sprouting (PHS) is a serious problem in rice production as it leads to reductions in grain yield and quality. However, the underlying mechanism of PHS in rice remains unclear. In this study, we identified and characterized a preharvest sprouting and seedling lethal (phssl) mutant. The heterozygous phssl/+ mutant exhibited normal plant development, but severe PHS in paddy fields. However, the homozygous phssl mutant was seedling lethal. Gene cloning and genetic analysis revealed that a point mutation in OsABA3 was responsible for the mutant phenotypes. OsABA3 encodes a molybdenum cofactor (Moco) sulfurase. The activities of the sulfureted Moco-dependent enzymes such as aldehyde oxidase (AO) and xanthine dehydrogenase (XDH) were barely detectable in the phssl mutant. As the final step of abscisic acid (ABA) de novo biosynthesis is catalyzed by AO, it indicated that ABA biosynthesis was interrupted in the phssl mutant. Exogenous application of ABA almost recovered seed dormancy of the phssl mutant. The knock-out (ko) mutants of OsABA3 generated by CRISPR-Cas9 assay, were also seedling lethal, and the heterozygous mutants were similar to the phssl/+ mutant showing reduced seed dormancy and severe PHS in paddy fields. In contrast, the OsABA3 overexpressing (OE) plants displayed a significant increase in seed dormancy and enhanced plant resistance to PHS. The AO and XDH activities were abolished in the ko mutants, whereas they were increased in the OE plants. Notably, the Moco-dependent enzymes including nitrate reductase (NR) and sulfite oxidase (SO) showed reduced activities in the OE plants. Moreover, the OE plants exhibited enhanced resistances to osmotic stress and bacterial blight, and flowered earlier without any reduction in grain yield. Taken together, this study uncovered the crucial functions of OsABA3 in Moco sulfuration, plant development, and stress resistance, and suggested that OsABA3 is a promising target gene for rice breeding. [ABSTRACT FROM AUTHOR]

Defining the seed dormancy profile (SDP) of plant communities may provide insight into species adaptive mechanisms, community structure, and dynamics. Golestan National Park (GNP) in Iran consists of different types of vegetation, namely deciduous temperate forest, matorral, and steppe in close proximity but with variability of environmental factors. Plant species, life forms, and kinds of seed dormancy were determined in the three vegetation types, and a SDP of types was generated and compared with corresponding ones in the world database. In all GNP vegetation types, 80%–82% and 2%–3% of the species had dormant (D), and nondormant (ND) seeds, respectively, but in 17% the class of dormancy was unknown. Physiological dormancy (PD) was the most abundant followed by physical dormancy (PY). The species percentage with ND seeds in GNP was significantly two or three times lower than that in the world database. The PD percentage in the matorral was significantly higher than that in the world database. The PY percentage was higher in the forests but lower in the matorral and steppe compared with the world database. The morphophysiological (MPD) dormancy percentage was significantly lower in the forests but higher in the matorral and steppe than in the global database. Seed dormancy profiles were not affected by the proximity of vegetation types in the GNP, but they differed from those of the world database for each vegetation type. The past climatic fluctuations associated with the present‐day seasonality of the region might be the selective pressure for the increased percentage of species with D seeds in the GNP. [ABSTRACT FROM AUTHOR]

Wheat is one of the most important food crops globally, and understanding the regulation of grain size is crucial for wheat breeding to achieve a higher grain yield. MicroRNAs (miRNAs) play vital roles in plant growth and development. However, the miRNA-mediated mechanism underlying grain size regulation remains largely elusive in wheat. Here, we report the characterization and functional validation of a miRNA, TamiR397a, associated with grain size regulation in wheat. The function of three TaMIR397 homoeologs was determined through histochemical β-glucuronidase-dependent assay. MiRNA expression was detected using quantitative reverse transcription polymerase chain reaction (qRT-PCR), and the function of TamiR397a was validated through its transgenic overexpression and repression in wheat. It was found that TaMIR397-6A and TaMIR397-6B encode active TamiR397a. The expression profiling indicated that TamiR397a was differentially expressed in various tissues and gradually up-regulated during grain filling. The inhibition of TamiR397a perturbed grain development, leading to a decrease in grain size and weight. Conversely, the overexpression of TamiR397a resulted in increased grain size and weight by accelerating the grain filling process. Transcriptome analysis revealed that TamiR397a regulates a set of genes involved in hormone response, desiccation tolerance, regulation of cellular senescence, seed dormancy, and seed maturation biological processes, which are important for grain development. Among the down-regulated genes in the grains of the TamiR397a-overexpressing transgenic plants, 11 putative targets of the miRNA were identified. Taken together, our results demonstrate that TamiR397a is a positive regulator of grain size and weight, offering potential targets for breeding wheat with an increased grain yield. [ABSTRACT FROM AUTHOR]

SUMMARY: Abscisic acid (ABA) signaling interacts frequently with auxin signaling when it regulates plant development, affecting multiple physiological processes; however, to the best of our knowledge, their interaction during tomato development has not yet been reported. Here, we found that type 2C protein phosphatase (SlPP2C2) interacts with both flavin monooxygenase FZY, an indole‐3‐acetic acid (IAA) biosynthetic enzyme, and small auxin upregulated RNA (SAUR) of an IAA signaling protein and regulates their activity, thereby affecting the expression of IAA‐responsive genes. The expression level of SlPP2C2 was increased by exogenous ABA, IAA, NaCl, or dehydration treatment of fruits, leaves, and seeds, and it decreased in imbibed seeds. Manipulating SlPP2C2 with overexpression, RNA interference, and CRISPR/Cas9‐mediated genome editing resulted in pleiotropic changes, such as morphological changes in leaves, stem trichomes, floral organs and fruits, accompanied by alterations in IAA and ABA levels. Furthermore, the RNA‐seq analysis indicated that SlPP2C2 regulates the expression of auxin‐/IAA‐responsive genes in different tissues of tomato. The results demonstrate that SlPP2C2‐mediated ABA signaling regulates the development of both vegetative and reproductive organs via interaction with FZY/SAUR, which integrates the cross‐talk of ABA and auxin signals during development and affects the expressions of development‐related genes in tomato. Significance Statement: SlPP2C2 regulates tomato development by integrating ABA and auxin signals through interaction with FZY/SAUR. This finding extends our knowledge of ABA signal cross talk in regulation of tomato development. [ABSTRACT FROM AUTHOR]

SUMMARY: Several dwarf and semi‐dwarf genes have been identified in barley. However, only a limited number have been effectively utilized in breeding programs to cultivate lodging resistant varieties. This is due to the common association of dwarf and semi‐dwarf traits with negative effects on malt quality. In this study, we employed gene editing to generate three new haplotypes of sdw1/denso candidate gene gibberellin (GA) 20‐oxidase2 (GA20ox2). These haplotypes induced a dwarfing phenotype and enhancing yield potential, and promoting seed dormancy, thereby reducing pre‐harvest sprouting. Moreover, β‐amylase activity in the grains of the mutant lines was significantly increased, which is beneficial for malt quality. The haplotype analysis revealed significant genetic divergence of this gene during barley domestication and selection. A novel allele (sdw1.ZU9), containing a 96‐bp fragment in the promoter region of HvGA20ox2, was discovered and primarily observed in East Asian and Russian barley varieties. The 96‐bp fragment was associated with lower gene expression, leading to lower plant height but higher germination rate. In conclusion, HvGA20ox2 can be potentially used to develop semi‐dwarf barley cultivars with high yield and improved malt quality. Significance Statement: Gene editing of HvGA20ox2 led to reduced plant height, improved yield potential, and pre‐harvest sprouting in barley. A novel allele sdw1.ZU9 containing a 96‐bp fragment located in the promoter region of HvGA20ox2 results in suppression of the gene expression, leading to reduced plant height and increased germination rate. [ABSTRACT FROM AUTHOR]

[Display omitted] Stem cells remain in a quiescent state for long-term maintenance and preservation of potency; this process requires fine-tuning regulatory mechanisms. In this study, we identified the epigenetic landscape along the developmental trajectory of skeletal stem cells (SSCs) in skeletogenesis governed by a key regulator, Ptip (also known as Paxip1, Pax interaction with transcription-activation domain protein-1). Our results showed that Ptip is required for maintaining the quiescence and potency of SSCs, and loss of Ptip in type II collagen (Col2)+ progenitors causes abnormal activation and differentiation of SSCs, impaired growth plate morphogenesis, and long bone dysplasia. We also found that Ptip suppressed the glycolysis of SSCs through downregulation of phosphoglycerate kinase 1 (Pgk1) by repressing histone H3 lysine 27 acetylation (H3K27ac) at the promoter region. Notably, inhibition of glycolysis improved the function of SSCs despite Ptip deficiency. To the best of our knowledge, this is the first study to establish an epigenetic framework based on Ptip, which safeguards skeletal stem cell quiescence and potency through metabolic control. This framework is expected to improve SSC-based treatments of bone developmental disorders. [ABSTRACT FROM AUTHOR]

Multiple processes control quiescence of muscle stem cells (MuSCs), which is instrumental to guarantee long-term replenishment of the stem cell pool. Here, we describe that the G-proteins G12-G13 integrate signals from different G-protein-coupled receptors (GPCRs) to control MuSC quiescence via activation of RhoA. Comprehensive screening of GPCR ligands identified two MuSC-niche-derived factors, endothelin-3 (ET-3) and neurotensin (NT), which activate G12-G13 signaling in MuSCs. Stimulation with ET-3 or NT prevented MuSC activation, whereas pharmacological inhibition of ET-3 or NT attenuated MuSC quiescence. Inactivation of Gna12-Gna13 or Rhoa but not of Gnaq-Gna11 completely abrogated MuSC quiescence, which depleted the MuSC pool and was associated with accelerated sarcopenia during aging. Expression of constitutively active RhoA prevented exit from quiescence in Gna12-Gna13 mutant MuSCs, inhibiting cell cycle entry and differentiation via Rock and formins without affecting Rac1-dependent MuSC projections, a hallmark of quiescent MuSCs. The study uncovers a critical role of G12-G13 and RhoA signaling for active regulation of MuSC quiescence. [ABSTRACT FROM AUTHOR]

Despite their crucial role in determining the fate of seeds, the type and breaking mode of seed dormancy in peatland plants in temperate Asia with a continental monsoon climate are rarely known. Fifteen common peatland plant species were used to test their seed germination response to various dormancy‐breaking treatments, including dry storage (D), gibberellin acid soaking (GA), cold stratification (CS), warm followed cold stratification (WCS), GA soaking + cold stratification (GA + CS) and GA soaking + warm followed cold stratification (GA + WCS). Germination experiment, viability and imbibition test, and morphological observation of embryos were conducted. Of the 15 species, nine showed physiological dormancy (PD), with non‐deep PD being the dominant type. Four species, Angelica pubescens, Cicuta virosa, Iris laevigata, and Iris setosa exhibited morphophysiological dormancy. Two species, Lycopus uniflorus and Spiraea salicifolia, demonstrated nondormancy. Overall, the effect hierarchy of dormancy‐breaking is: CS > GA > WCS > GA + CS > D > GA + WCS. Principal component analysis demonstrated that seed traits, including embryo length: seed length ratio, seed size, and monocot/eudicot divergence, are more likely to influence seed dormancy than environmental factors. Our study suggests that nearly 90% of the tested peatland plant species in the Changbai Mountains demonstrated seed dormancy, and seed traits (e.g. embryo‐to‐seed ratio and seed size) and abiotic environmental factors (e.g. pH and temperature seasonality) are related to germination behavior, suggesting seed dormancy being a common adaptation strategy for the peatland plants in the temperate montane environment. [ABSTRACT FROM AUTHOR]

Seed germination and dormancy represent critical phases in the life cycle of plants, tightly regulated by endogenous phytochrome levels and environment signals. High temperatures (HT) induce the overaccumulation of reactive oxygen species (ROS) and increase abscisic acid (ABA), thereby inhibiting seed germination. Our previous findings showed that HT induced the burst of reactive nitrogen species (RNS), increasing the S‐nitrosylation modification of HFR1, which effectively blocks seed germination. Importantly, stabilizing HFR1 has been shown to significantly mitigate the inhibitory effect of HT on seed germination. In this study, we reported that HT increased the protein abundance of ABI4, a crucial component in ABA signaling, which in turn activates the expression of RbohD while suppressing the expression of VTC2. This leads to the rapid generation of ROS, thereby inhibiting seed germination. Consistently, the seed germination of abi4 mutant showed insensitivity to HT with lower ROS level during seed germination, whereas transgenic lines overexpressing ABI4 showed reduced germination rates accompanied by elevated ROS levels. Furthermore, we noted that HFR1 interacts with ABI4 to sequester its activity under normal conditions. However, HT‐induced ROS triggered the degradation of HFR1, consequently releasing ABI4 activity. This activation of ABI4 promotes RbohD expression, culminating in a ROS burst that suppresses seed germination. Thus, our study unveils a novel function for ABI4 in regulating ROS level and seed germination under HT stress. Throughout this process, HFR1 plays a critical role in restraining ABI4 activity to maintain an optimal endogenous ROS level, thereby ensuring seed germination under favorable environmental conditions. [ABSTRACT FROM AUTHOR]

Hematopoietic stem cells (HSCs) replenish blood cells under steady state and on demand, that exhibit therapeutic potential for Bone marrow failures and leukemia. Redox signaling plays key role in immune cells and hematopoiesis. However, the role of reactive nitrogen species in hematopoiesis remains unclear and requires further investigation. We investigated the significance of inducible nitric oxide synthase/nitric oxide (iNOS/NO) signaling in hematopoietic stem and progenitor cells (HSPCs) and hematopoiesis under steady-state and stress conditions. HSCs contain low levels of NO and iNOS under normal conditions, but these increase upon bone marrow stress. iNOS-deficient mice showed subtle changes in peripheral blood cells but significant alterations in HSPCs, including increased HSCs and multipotent progenitors. Surprisingly, iNOS-deficient mice displayed heightened susceptibility and delayed recovery of blood progeny following 5-Fluorouracil (5-FU) induced hematopoietic stress. Loss of quiescence and increased mitochondrial stress, indicated by elevated MitoSOX and MMPhi HSCs, were observed in iNOS-deficient mice. Furthermore, pharmacological approaches to mitigate mitochondrial stress rescued 5-FU-induced HSC death. Conversely, iNOS-NO signaling was required for demand-driven mitochondrial activity and proliferation during hematopoietic recovery, as iNOS-deficient mice and NO signaling inhibitors exhibit reduced mitochondrial activity. In conclusion, our study challenges the conventional view of iNOS-derived NO as a cytotoxic molecule and highlights its intriguing role in HSPCs. Together, our findings provide insights into the crucial role of the iNOS–NO–mitochondrial axis in regulating HSPCs and hematopoiesis. [Display omitted] • Under steady-state conditions, HSPCs maintain low levels of NO and iNOS, which increase in response to 5-FU-induced stress. • iNOS deficiency significantly changed the HSPC compartment and caused increased mitochondrial stress, and loss of quiescency. • Loss of iNOS led to delayed hematopoietic recovery, and heightened susceptibility to bone marrow stress. • iNOS-NO signaling is essential for demand-derived mitochondrial activity during hematopoietic recovery. [ABSTRACT FROM AUTHOR]

Breeding high yielding groundnut cultivars with 2–3 weeks of fresh seed dormancy, particularly in Spanish-type cultivars, enhances the sustainability of agriculture in groundnuts. In this context, we conducted a comprehensive phenotypic and genotypic evaluation of advanced breeding lines developed in the genetic background of Spanish types. By employing multi-phenotyping and marker data, we identified PBS 15044, 16004, 16013, 16015, 16016, 16017, 16020, 16021, 16026, 16031, 16035, 16037, 16038, 16039, 16041, and 16042 with 2–3 weeks dormancy (> 90%).The various parametric and non-parametric estimates identified the stable fresh dormant genotypes with one or more superior economic trait. PBS 16021, 15044, 16038, and 16039 identified with high hundred pod weight (HPW) were also reported having high intensity of dormancy (> 90% for up to 3 weeks); PBS 15044, 16016, PBS 16038 and PBS 16039 with high hundred kernel weight (HKW) also reported with up to 3 weeks fresh seed dormancy; and PBS 16013, 16031, and 16038 with up to 3 weeks fresh seed dormancy had high shelling percentage (SP). They can be used to develop lines with the desired level of dormancy, and high yields, by designing appropriate breeding strategies. [ABSTRACT FROM AUTHOR]

Summary: Crops generally have seeds larger than their wild progenitors´ and with reduced dormancy. In wild plants, seed mass and allocation to the seed coat (a proxy for physical dormancy) scale allometrically so that larger seeds tend to allocate less to the coats. Larger seeds and lightweight coats might thus have evolved as correlated traits in crops.We tested whether 34 crops and 22 of their wild progenitors fit the allometry described in the literature, which would indicate co‐selection of both traits during crop evolution. Deviations from the allometry would suggest that other evolutionary processes contribute to explain the emergence of larger, lightweight‐coated seeds in crops.Crops fitted the scaling slope but deviated from its intercept in a consistent way: Seed coats of crops were lighter than expected by their seed size. The wild progenitors of crops displayed the same trend, indicating that deviations cannot be solely attributed to artificial selection during or after domestication.The evolution of seeds with small coats in crops likely resulted from a combination of various pressures, including the selection of wild progenitors with coats smaller than other wild plants, further decreases during early evolution under cultivation, and indirect selection due to the seed coat‐seed size allometry. [ABSTRACT FROM AUTHOR]

Key message: The major QTL Sdp1.1+ controlling seed dormancy in cowpea was finely mapped, and two CCoAOMT1 genes were identified as candidate genes for the dormancy. Seed dormancy in wild cowpea may be useful in breeding cultivated cowpea with pre-harvest sprouting resistance. A previous study identified a major quantitative trait locus (QTL) for seed dormancy, Sdp1.1+ , using the population of the cross between cultivated cowpea 'JP81610' and wild cowpea 'JP89083.' However, the molecular basis of seed dormancy in cowpea is not yet known. In this study, we aimed to finely map the locus Sdp1.1+ and identify candidate gene(s) for it. Germination tests demonstrated that the seed coat is the major factor controlling seed dormancy in the wild cowpea JP89083. Microscopic observations revealed that wild cowpea seeds, unlike cultivated cowpea seeds, possessed a palisade cuticle layer. Fine mapping using a large F2 population of the cross JP81610 × JP89083 grown in Thailand revealed a single QTL, Sdp1.1+ , controlling seed dormancy. The Sdp1.1+ was confirmed using a small F2 population of the same cross grown in Japan. The Sdp1.1+ was mapped to a 37.34-Kb region containing three genes. Two closely linked genes, Vigun03g278900 (VuCCoAOMT1a) and Vigun03g290000 (VuCCoAOMT1b), located 4.844 Kb apart were considered as candidate genes for seed dormancy. The two genes encoded caffeoyl coenzyme A O-methyltransferase 1 (CCoAOMT1). DNA sequencing and alignment of VuCCoAOMT1a and VuCCoAOMT1b between JP89083 and JP81610 revealed a single nucleotide polymorphism (SNP) causing an amino acid change in VuCCoAOMT1a and several SNPs leading to six amino acid changes in VuCCoAOMT1b. Altogether, these results indicate that VuCCoAOMT1a and VuCCoAOMT1b are candidate genes controlling physical seed dormancy in the wild cowpea JP89083. [ABSTRACT FROM AUTHOR]

Plants in habitats with unpredictable conditions often have diversified bet-hedging strategies that ensure fitness over a wider range of variable environmental factors. A striking example is the diaspore (seed and fruit) heteromorphism that evolved to maximize species survival in Aethionema arabicum (Brassicaceae) in which external and endogenous triggers allow the production of two distinct diaspores on the same plant. Using this dimorphic diaspore model, we identified contrasting molecular, biophysical, and ecophysiological mechanisms in the germination responses to different temperatures of the mucilaginous seeds (M+ seed morphs), the dispersed indehiscent fruits (IND fruit morphs), and the bare non-mucilaginous M− seeds obtained by pericarp (fruit coat) removal from IND fruits. Large-scale comparative transcriptome and hormone analyses of M+ seeds, IND fruits, and M− seeds provided comprehensive datasets for their distinct thermal responses. Morph-specific differences in co-expressed gene modules in seeds, as well as in seed and pericarp hormone contents, identified a role of the IND pericarp in imposing coat dormancy by generating hypoxia affecting abscisic acid (ABA) sensitivity. This involved expression of morph-specific transcription factors, hypoxia response, and cell wall remodeling genes, as well as altered ABA metabolism, transport, and signaling. Parental temperature affected ABA contents and ABA-related gene expression and altered IND pericarp biomechanical properties. Elucidating the molecular framework underlying the diaspore heteromorphism can provide insight into developmental responses to globally changing temperatures. Aethionema arabicum is an outstanding model to understand the plastic developmental and environmental control of the dimorphic seed/fruit bet-hedging trait relevant to adaptation to abiotic stress. [ABSTRACT FROM AUTHOR]

Helleborus thibetanus is an endemic species in China with important ornamental and medicinal value. However, the seeds have dormancy, and their germination percentage is low under natural conditions. This research was carried out to determine the seed germination requirements of H. thibetanus and to characterize the type of seed dormancy. The morphological post-ripening process of the seed embryo was studied according to the morphological anatomy, and the effects of temperature and gibberellic acid (GA3) on seed germination were investigated in H. thibetanus. The H. thibetanus seeds had a heart-shaped embryo at maturity. The embryo fully grew within the seed through warm stratification, and the embryo/seed ratio increased from 8.58% to 42.6%. The shortest time for a radicle to emerge (58.33 d) and the highest radicle emergence percentage (84.44%) were obtained at a temperature of 15 °C. The results showed that the H. thibetanus seeds had a morphophysiological dormancy. In addition, 300 mg/L GA3 treatments shortened the time of warm stratification and increased the radicle emergence percentage. Seeds with emerged radicles could not emerge epicotyl–plumule without cold stratification, which showed that the H. thibetanus seeds had epicotyl physiological dormancy. The length of the roots, cold stratification time, and GA3 markedly affected the release of the epicotyl physiological dormancy in H. thibetanus. The seeds with 2.5 cm roots required the shortest time to break their dormancy (50 d), and the epicotyl–plumule emergence percentage was the highest. Additionally, GA3 treatment also shortened the incubation time in cold stratification (5 °C) and successfully broke the epicotyl physiological dormancy. Our study showed that H. thibetanus seeds exhibited deep simple epicotyl morphophysiological dormancy. Temperature, GA3, and duration of stratification played vital roles in the seed germination of H. thibetanus. This research will provide valuable data for seed germination and practical dormancy-breaking techniques and will promote the cultivation and conventional crossbreeding of H. thibetanus. [ABSTRACT FROM AUTHOR]

Abstract Purpose Epimedium brevicornu Maxim. is a perennial persistent C3 plant of the genus Epimedium Linn. in the family Berberaceae that exhibits severe physiological and morphological seed dormancy.We placed mature E. brevicornu seeds under nine stratification treatment conditions and explored the mechanisms of influence by combining seed embryo growth status assessment with related metabolic pathways and gene co-expression analysis. Results We identified 3.9 °C as the optimum cold-stratification temperature of E. brevicornu seeds via a chilling unit (CU) model. The best treatment was variable-temperature stratification (10/20 °C, 12/12 h) for 4 months followed by low-temperature stratification (4 °C) for 3 months (4-3). A total of 63801 differentially expressed genes were annotated to 2587 transcription factors (TFs) in 17 clusters in nine treatments (0-0, 0-3, 1-3, 2-3, 3-3, 4-3, 4-2, 4-1, 4-0). Genes specifically highly expressed in the dormancy release treatment group were significantly enriched in embryo development ending in seed dormancy and fatty acid degradation, indicating the importance of these two processes. Coexpression analysis implied that the TF GRF had the most reciprocal relationships with genes, and multiple interactions centred on zf-HD and YABBY as well as on MYB, GRF, and TCP were observed. Conclusion In this study, analyses of plant hormone signal pathways and fatty acid degradation pathways revealed changes in key genes during the dormancy release of E. brevicornu seeds, providing evidence for the filtering of E. brevicornu seed dormancy-related genes.

Abstract Preharvest sprouting (PHS) is a serious problem in rice production as it leads to reductions in grain yield and quality. However, the underlying mechanism of PHS in rice remains unclear. In this study, we identified and characterized a preharvest sprouting and seedling lethal (phssl) mutant. The heterozygous phssl/+ mutant exhibited normal plant development, but severe PHS in paddy fields. However, the homozygous phssl mutant was seedling lethal. Gene cloning and genetic analysis revealed that a point mutation in OsABA3 was responsible for the mutant phenotypes. OsABA3 encodes a molybdenum cofactor (Moco) sulfurase. The activities of the sulfureted Moco-dependent enzymes such as aldehyde oxidase (AO) and xanthine dehydrogenase (XDH) were barely detectable in the phssl mutant. As the final step of abscisic acid (ABA) de novo biosynthesis is catalyzed by AO, it indicated that ABA biosynthesis was interrupted in the phssl mutant. Exogenous application of ABA almost recovered seed dormancy of the phssl mutant. The knock-out (ko) mutants of OsABA3 generated by CRISPR-Cas9 assay, were also seedling lethal, and the heterozygous mutants were similar to the phssl/+ mutant showing reduced seed dormancy and severe PHS in paddy fields. In contrast, the OsABA3 overexpressing (OE) plants displayed a significant increase in seed dormancy and enhanced plant resistance to PHS. The AO and XDH activities were abolished in the ko mutants, whereas they were increased in the OE plants. Notably, the Moco-dependent enzymes including nitrate reductase (NR) and sulfite oxidase (SO) showed reduced activities in the OE plants. Moreover, the OE plants exhibited enhanced resistances to osmotic stress and bacterial blight, and flowered earlier without any reduction in grain yield. Taken together, this study uncovered the crucial functions of OsABA3 in Moco sulfuration, plant development, and stress resistance, and suggested that OsABA3 is a promising target gene for rice breeding.

Brassinosteroid (BR) is a hormone known for its crucial role in seed germination promotion. However, there is a limited understanding of potential application in tobacco seed. In this study, we investigated various active ingredients for seed coating to enhance tobacco seed germination. It revealed that seed coating with 0.0500 ppm BR and priming with 0.01 ppm BR significantly increased seed germination rates, especially in low-temperature conditions. In addition, the combined use BR with priming and seed coating exhibited a substantial improvement in seed germination rates and promoted seedling growth. Through transcriptional analysis, it found that BR treatment regulates the expression of genes associated with DNA synthesis, cell wall organization and glucan metabolic process involved in seed dormancy and seedling growth. Overall, these results provide valuable insights into the utilization of seed coating and priming techniques, particularly with the inclusion of BR, to enhance tobacco seed germination and facilitate seedling emergence. [ABSTRACT FROM AUTHOR]

Abstract Background Class III peroxidases (PODs) perform crucial functions in various developmental processes and responses to biotic and abiotic stresses. However, their roles in wheat seed dormancy (SD) and germination remain elusive. Results Here, we identified a wheat class III POD gene, named TaPer12-3A, based on transcriptome data and expression analysis. TaPer12-3A showed decreasing and increasing expression trends with SD acquisition and release, respectively. It was highly expressed in wheat seeds and localized in the endoplasmic reticulum and cytoplasm. Germination tests were performed using the transgenic Arabidopsis and rice lines as well as wheat mutant mutagenized with ethyl methane sulfonate (EMS) in Jing 411 (J411) background. These results indicated that TaPer12-3A negatively regulated SD and positively mediated germination. Further studies showed that TaPer12-3A maintained H2O2 homeostasis by scavenging excess H2O2 and participated in the biosynthesis and catabolism pathways of gibberellic acid and abscisic acid to regulate SD and germination. Conclusion These findings not only provide new insights for future functional analysis of TaPer12-3A in regulating wheat SD and germination but also provide a target gene for breeding wheat varieties with high pre-harvest sprouting resistance by gene editing technology.

Suaeda glauca Bunge produces dimorphic seeds on the same plant, with brown seeds displaying non-dormant characteristics and black seeds exhibiting intermediate physiological dormancy traits. Previous studies have shown that black seeds have a very low germination rate under natural conditions, but exogenous GA3 effectively enhanced the germination rate of black seeds. However, the physiological and molecular mechanisms underlying the effects of GA3 on S. glauca black seeds are still unclear. In this study, transcriptomic profiles of seeds at different germination stages with and without GA3 treatment were analyzed and compared, and the TTF, H2O2, O2–, starch, and soluble sugar contents of the corresponding seed samples were determined. The results indicated that exogenous GA3 treatment significantly increased seed vigor, H2O2, and O2– contents but decreased starch and soluble sugar contents of S. glauca black seeds during seed dormancy release. RNA-seq results showed that a total of 1136 DEGs were identified in three comparison groups and were involved mainly in plant hormone signal transduction, diterpenoid biosynthesis, flavonoid biosynthesis, phenylpropanoid biosynthesis, and carbohydrate metabolism pathway. Among them, the DEGs related to diterpenoid biosynthesis (SgGA3ox1, SgKAO and SgGA2ox8) and ABA signal transduction (SgPP2Cs) could play important roles during seed dormancy release. Most genes involved in phenylpropanoid biosynthesis were activated under GA3 treatment conditions, especially many SgPER genes encoding peroxidase. In addition, exogenous GA3 treatment also significantly enhanced the expression of genes involved in flavonoid synthesis, which might be beneficial to seed dormancy release. In accordance with the decline in starch and soluble sugar contents, 15 genes involved in carbohydrate metabolism were significantly up-regulated during GA3-induced dormancy release, such as SgBAM, SgHXK2, and SgAGLU, etc. In a word, exogenous GA3 effectively increased the germination rate and seed vigor of S. glauca black seeds by mediating the metabolic process or signal transduction of plant hormones, phenylpropanoid and flavonoid biosynthesis, and carbohydrate metabolism processes. Our results provide novel insights into the transcriptional regulation mechanism of exogenous GA3 on the dormancy release of S. glauca black seeds. The candidate genes identified in this study may be further studied and used to enrich our knowledge of seed dormancy and germination. [ABSTRACT FROM AUTHOR]

Background: Adult skeletal muscle contains resident muscle stem cells (MuSC) with high myogenic and engraftment potentials, making them suitable for cell therapy and regenerative medicine approaches. However, purification process of MuSC remains a major hurdle to their use in the clinic. Indeed, muscle tissue enzymatic dissociation triggers a massive activation of stress signaling pathways, among which P38 and JNK MAPK, associated with a premature loss of MuSC quiescence. While the role of these pathways in the myogenic progression of MuSC is well established, the extent to which their dissociation-induced activation affects the functionality of these cells remains unexplored. Methods: We assessed the effect of P38 and JNK MAPK induction on stemness marker expression and MuSC activation state during isolation by pharmacological approaches. MuSC functionality was evaluated by in vitro assays and in vivo transplantation experiments. We performed a comparative analysis of the transcriptome of human MuSC purified with pharmacological inhibitors of P38 and JNK MAPK (SB202190 and SP600125, respectively) versus available RNAseq resources. Results: We monitored PAX7 protein levels in murine MuSC during muscle dissociation and demonstrated a two-step decline partly dependent on P38 and JNK MAPK activities. We showed that simultaneous inhibition of these pathways throughout the MuSC isolation process preserves the expression of stemness markers and limits their premature activation, leading to improved survival and amplification in vitro as well as increased engraftment in vivo. Through a comparative RNAseq analysis of freshly isolated human MuSC, we provide evidence that our findings in murine MuSC could be relevant to human MuSC. Based on these findings, we implemented a purification strategy, significantly improving the recovery yields of human MuSC. Conclusion: Our study highlights the pharmacological limitation of P38 and JNK MAPK activities as a suitable strategy to qualitatively and quantitatively ameliorate human MuSC purification process, which could be of great interest for cell-based therapies. [ABSTRACT FROM AUTHOR]

Tree species’ ability to persist within their current distribution ranges is determined by seed germination and seedling growth. Exploring variation in these traits in relation to climatic conditions helps to understand and predict tree population dynamics, and to support species management and conservation under future climate. We analyzed seeds and seedlings of 26 European beech populations from the northeastern boundary of the species range to test whether: 1) adaptation to climatic conditions is reflected in depth of dormancy and germination of seeds; 2) climatic characteristics of origin predictably affect seedling traits. The variation in seed dormancy and germination in a laboratory test, and seedling growth and morphology traits in a nursery common-garden test was examined. Populations originating from warmer and drier sites (mostly from the northern region), compared to those from the opposite end of climatic gradient, germinated later, with a lower success, and produced seedlings with shorter and tougher roots. They had deeper dormancy and poorer seed germination capacity, and are likely more vulnerable to environmental changes. The climatic conditions at the origin shape the intraspecific variation of seed germination and seedling traits, and may limit regeneration from seed and affect adaptation potential of beech to increasing temperatures and decreasing precipitation. [ABSTRACT FROM AUTHOR]

Stewartia ovata (cav.) Weatherby, commonly known as mountain stewartia, is an understory tree native to the southeastern United States (U.S.). This relatively rare species occurs in isolated populations in Virginia, Kentucky, Tennessee, North Carolina, South Carolina, Georgia, Alabama, and Mississippi. As a species, S. ovata has largely been overlooked, and limited information is available regarding its ecology, which presents obstacles to conservation efforts. Stewartia ovata has vibrant, large white flowers that bloom in summer with a variety of filament colors, suggesting potential horticultural traits prized by ornamental industry. However, S. ovata is relatively slow growing and, due to long seed dormancy, propagation is challenging with limited success rates. This has created a need to assess the present genetic diversity in S. ovata populations to inform potential conservation and restoration of the species. Here, we employ a genotyping‐by‐sequencing (GBS) approach to characterize the spatial distribution and genetic diversity of S. ovata in the southern Appalachia region of the eastern United States. A total of 4475 single nucleotide polymorphisms (SNPs) were identified across 147 individuals from 11 collection sites. Our results indicate low genetic diversity (He = 0.216), the presence of population structure (K = 2), limited differentiation (FST = 0.039), and high gene flow (Nm = 6.16) between our subpopulations. Principal component analysis corroborated the findings of STRUCTURE, confirming the presence of two distinct S. ovata subpopulations. One subpopulation mainly contains genotypes from the Cumberland Plateau, Tennessee, while the other consists of genotypes present in the Great Smoky Mountain ranges in Tennessee, North Carolina, and portions of Nantahala, Chattahoochee‐Oconee national forests in Georgia, highlighting that elevation likely plays a major role in its distribution. Our results further suggested low inbreeding coefficient (FIS = 0.070), which is expected with an outcrossing tree species. This research further provides necessary insight into extant subpopulations and has generated valuable resources needed for conservation efforts of S. ovata. [ABSTRACT FROM AUTHOR]

The article discusses the need for mechanistic explanations in seed ecology and highlights the limitations of broad-scale correlative studies that ignore mechanisms. The authors specifically focus on seed dormancy and argue that the current understanding of seed dormancy as an adaptive response to climate seasonality is flawed. They propose that fire regime, rather than climate seasonality, is a more plausible mechanism for selecting prolonged seed dormancy. The article also mentions similar issues in other areas of ecology, such as species diversity and trait ecology, and emphasizes the importance of a mechanistic understanding and hypothesis-driven research. [Extracted from the article]

Paris polyphylla var. yunnanensis, a well-known Chinese medicinal herb, shows a unique physiological trait characterized by the cyclic opening and closing of its anthers after pollen maturation. The aim of this study was to explore the implications of this phenomenon on breeding. RNA sequencing coupled with methylation sequencing was used to scrutinize and compare gene expression profiles and methylation alterations in pollen and seeds during anther opening and closing, along with cold exposure. Genes enriched within Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways were examined to identify gene clusters susceptible to temperature-related methylation changes in both pollen and seeds. Four pollen treatment models, namely, normal control, "pollen protected from low temperatures," "pollen from just-opened anther," and "pollen from close-blocked anther," were used to produce corresponding seeds via artificial pollination. Subsequently, qRT-PCR was used to validate modifications in the expression patterns of marker genes in pollinated seeds under diverse treatment scenarios. Genes exhibiting significant differences in expression between anthers and normal tissues, along with gene regions linked to methylation variations attributed to low-temperature-treated pollen and seeds, were identified through transcriptomic analysis. Convergence was observed in three signaling pathways: oxidative phosphorylation (ko00190), plant hormone signal transduction (Ko04075), and zeatin biosynthesis (ko00908). Notably, gene clusters prone to temperature-induced methylation changes, such as NADH-ubiquinone oxidoreductase chain 5, plasma membrane ATPase 4, cytochrome c oxidase subunit 2, cis-zeatin O-glucosyltransferase, ABSCISIC ACID-INSENSITIVE 5-like protein 4, and indole-3-acetic acid-amido synthetase (IAAS), were identified. Evaluation using various pollen pollination models revealed altered expression patterns of five dormancy-regulating marker genes: IAAS, sucrose synthase (SUS), gibberellin 2-oxidase (GA2ox), ABA INSENSITIVE 2 (ABI2), and auxin-repressed protein (ARP), in seeds pollinated with pollen from close-blocked anthers, cold-protected pollen, and pollen from freshly opened anthers. The close-blocked anther treatment led to significantly upregulated expression of IAAS, SUS, GA2ox, and ABI2, whereas ARP expression decreased markedly, indicating a propensity toward prolonged seed dormancy. Conversely, in the low-temperature-protected anther model, SUS, ARP, GA2ox, and IAAS exhibited reduced expression levels, whereas the expression of ABI2 was upregulated, overall facilitating seed germination. [ABSTRACT FROM AUTHOR]

Rice is a significant staple crop that provides food and livelihoods for millions of people worldwide. However, climate change and frequent cyclonic storms with heavy rains during grain maturation periods have led to a significant reduction in rice yield and quality (20–30%) due to pre-harvest sprouting (PHS) damage. PHS has become a widespread issue globally, resulting in significant economic losses for Indian farmers, amounting to billions of rupees annually and severely impacting the country’s economy. Developing protocol and PHS-resistant rice genotypes is essential to mitigate the significant economic losses experienced by farmers and meet the growing demand for food grain with the increasing population. This study was aimed to developing the efficient protocol to identify PHS-resistant rice genotypes by evaluating 96 genotypes under laboratory and field conditions at 20, 25, 30, 35 and 40 days after flowering (DAF). To evaluate the PHS resistant genotypes we have developed the efficient and standard protocol for the present study. The results showed a positive correlation between phenotypic responses under laboratory and field conditions. Based on the germination percentage exhibited under laboratory and field conditions, the genotypes were grouped into four clusters using K-clustering and dendrogram clustering analysis. Out of 96 genotypes evaluated 19 grouped as highly susceptible (45 to 88%), 14 were moderately susceptible (10 to 45%), 51 were moderately resistant (0.10 to 10.00%), and 12 were highly resistant with zero percent germination at all flowering stages. The study also evaluated the genotypes for days to germination from 20 to 40 DAF. The highly susceptible genotypes germinated earlier (3 days) than moderately susceptible and resistant genotypes (4 to 6 days). Zero days were assigned to highly resistant genotypes since no germination was recorded. In nutshell, the novel PHS-resistant rice genotypes identified in this study could serve as donors for future crop improvement programs. [ABSTRACT FROM AUTHOR]

Summary: Seed dormancy governs germination timing, with both evolutionary and applied consequences. Despite extensive studies on the hormonal and genetic control of these processes, molecular mechanisms directly linking dormancy and germination remain poorly understood.By screening a collection of lines overexpressing Arabidopsis transcription factors, we identified ERF50 as a key gene to control dormancy and germination. To study its regulation, we measured seed‐related physiological parameters in loss‐of‐function mutants and carried out transactivation, protein interaction and ChIP‐PCR analyses.We found direct ERF50‐mediated repression of DOG1 and activation of EXPA2 transcription, which results in enhanced seed germination. Although ERF50 expression is increased by DOG1 in dormant seeds, ERF50 germination‐promoting activity is blocked by RGL2.The physiological, genetic and molecular evidence gathered here supports that ERF50 controls germination timing by regulating DOG1 levels to leverage its role as enhancer of seed germination, via RGL2 antagonism on EXPA2 expression. Our results highlight the central role of ERF50 as a feedback regulator to couple and fine‐tune seed dormancy and germination. [ABSTRACT FROM AUTHOR]

Despite exhibiting intriguing features associated with its multipurpose applications and drought tolerance, Ferula communis remains a wild and uncultivated species, with limited experimental research on its biology, starting from seed germination and extending to its ecology. The purpose of this study was to investigate potential germination and kinetics in F. communis seeds in response to four cold stratification periods (0, 15, 45, and 90 days at a constant temperature of 5 °C) and four temperatures (5, 10, 15, and 20 °C) under continuous darkness. F. communis exhibited a pronounced germination potential exceeding 90%, with the optimal temperature for germination falling within the range of 5 °C to 15 °C, without necessitating cold stratification. A dramatic drop of the germination percentage was observed at 20 °C (<10%), suggesting a form of conditional dormancy attributed to the higher temperature tested. [ABSTRACT FROM AUTHOR]

As differences in seed dormancy between Actinidia species have not been reported previously, in this study we characterized the variation in the dormancy of seeds in 13 kiwifruit species that originated from different regions of China and Taiwan, and for which mature plants are now growing in New Zealand orchards. Dormancy-breaking treatments, including cold-moist stratification, seed coat scarification and soaking in water and gibberellic acid (GA3), were tested for their efficacy in alleviating dormancy and improving final germination and germination rates. In addition, we assessed seed viability using RNA integrity analysis to distinguish dead seeds from dormant seeds. This study identified that dormancy type in Actinidia seeds is species-specific and can be morphological, morphophysiological or a combination of physiological and physical, and that seed RNA integrity is a useful metric to incorporate into seed dormancy studies. Our results also suggest that species originating from colder climates that experience large differences between winter minimum and summer maximum temperatures exhibit physiological dormancy and require cold-moist stratification, contrasting with species originating in milder climates. Interestingly, although not all seeds from all the species were dormant, the proportion of dormant seeds in each species did not correlate to the climatic data of the region from which they originated. These findings provide new insights into mechanisms of seed dormancy in kiwifruit. [ABSTRACT FROM AUTHOR]