Search Results (414)

The “algarrobo” (Neltuma pallida) is a key tree species in the seasonally dry tropical forests in Equatorial Pacific coast of South America, currently at risk. Its regeneration depends on endozoochorous dispersal, in which seeds are ingested and later defecated by animals, helping to release and scarify them. We compared the role of the native white-tailed deer (Odocoileus virginianus peruvianus) and the introduced goat (Capra hircus) in seed dispersal. Seeds were recovered from the dung of both species after experimental feeding and from grazing goats in a fruiting N. pallida forest. Seed recovery was higher in deer dung (9.34%) than in goat dung (3.09%), and retention time was shorter in deer than in goats (peak at 48 and 84 h respectively). Only passage of seeds through the deer’s digestive tract significantly improved cumulative germination (63% vs. 44%) and germination rate (time to reach 25% germination, T25 = 8.98 days). Meanwhile, the passage of seeds through the goat’s digestive system reduced germination rate under experimental conditions (T25 = 19.25 days) but slightly increased it under forest conditions (T25 = 12.81 days), where goats ingest fruits constantly. Differences in seed recovery and germination are explained by the morphophysiological traits of ruminants. In conclusion, both goats and deer contribute to seed dispersal. White-tailed deer enhances seed germination (~66%), whereas goats maintain seed viability (~44%) and exhibit a longer seed retention time. During peak fruiting, alternating grazing between high-fruiting and degraded areas is recommended to maximize seed incorporation into the soil. Full article

The seeds of Polygonatum sibiricum exhibit dormancy, which poses a major challenge for its cultivation. To elucidate the regulatory mechanisms underlying dormancy release, we performed integrated transcriptomic and metabolomic analyses on seeds at 0, 5, 10, and 15 d after seed imbibition. Physiological assays revealed progressive declines in abscisic acid (ABA) and starch levels, alongside increases in gibberellin (GA) and soluble sugar contents, reflecting the metabolic changes accompanying the transition from dormancy to germination. Transcriptomic analysis identified 11,520 expressed genes, with 6753, 7775 and 9387 differentially expressed genes (DEGs) at T5, T10, and T15, respectively. KEGG enrichment highlighted starch and sucrose metabolism and plant hormone signal transduction as key pathways. Notably, the GA biosynthesis gene GA3ox was markedly upregulated, while the DELLA repressor (Isoform0012761) showed sustained downregulation, suggesting relieved GA signaling. In the ABA pathway, CYP707A catabolic genes exhibited biphasic expression, and ABA signaling components (PYL, PP2C, SnRK2) showed stage-specific remodeling. A total of 316, 412, and 479 differentially expressed transcription factors were identified across stages, with the GRAS family being the largest. Co-expression network analysis revealed 19 transcription factors integrating starch/sucrose metabolism with ABA and GA signaling, most of which were downregulated, except one C2H2 member showing sustained upregulation. These findings demonstrate that dormancy release in P. sibiricum is governed by coordinated hormonal reprogramming, metabolic mobilization, and transcription factor-mediated regulation, providing a theoretical foundation for improving seed germination in this medicinal plant. Full article

Seed dormancy is a vital adaptive mechanism regulated by the DELAY OF GERMINATION (DOG) gene family. Here, we present the first systematic genome-wide identification and expression profiling of the DOG gene family (RsDOGs) in radish (Raphanus sativus). Comprehensive analysis of physicochemical properties, chromosomal distribution, and phylogeny revealed strong evolutionary conservation alongside functional divergence. Notably, several RsDOG proteins harbor natural fusions of the DOG1 domain with a bZIP domain, suggesting potential transcription factor activity and novel regulatory functions. Promoter analysis identified abundant ABA-responsive and abiotic stress-responsive cis-acting elements. Quantitative real-time PCR (qRT-PCR) profiling across contrasting cultivars—dormant variety Rs275 and non-dormant variety Rs100—at 4 h and 28 h post-imbibition revealed distinct differential expression patterns. In particular, TRs0x5c022182.1 exhibited high expression levels in dormant seeds, suggesting its potential involvement in seed dormancy regulation in radish. This study provides key insights into the structural evolution and expression dynamics of RsDOG genes, laying a solid foundation for molecular breeding aimed at optimizing seed germination traits. Full article

The genus Astragalus comprises one of the largest and most ecologically diverse groups of flowering plants and includes species of major medicinal, forage, and restoration value, particularly Astragalus membranaceus and allied taxa. However, effective germplasm utilization and large-scale cultivation remain constrained by strong seed dormancy, most commonly expressed as physical dormancy imposed by a water-impermeable seed coat. In some species, this coat-imposed barrier is further complicated by an additional physiological component, resulting in combinational dormancy. This review synthesizes current knowledge on the structural, molecular, and multi-omics basis of seed dormancy and germination in Astragalus, with emphasis on the dormancy-to-germination transition. We first examine the anatomical basis of hardseededness, including the palisade layer, light line, and associated seed-coat barrier domains, and discuss the likely contributions of phenylpropanoid, lignin, suberin, and cutin biosynthesis to the establishment of physical dormancy. We then summarize current understanding of hormone crosstalk, highlighting the central roles of abscisic acid and gibberellins together with ethylene, brassinosteroids, reactive oxygen species, and nitric oxide in regulating post-dormancy germination. Recent transcriptomic, metabolomic, and emerging integrative omics studies reveal that Astragalus germination involves not only reserve mobilization and energy activation but also early induction of characteristic secondary-metabolite pathways, particularly flavonoids and isoflavonoids, which distinguishes medicinal Astragalus seeds from many conventional crop seeds. Finally, we discuss current bottlenecks, including the limited availability of robust functional-genomics tools, and outline future directions involving CRISPR-based validation, epigenetic regulation, and marker-assisted breeding for improved germination uniformity and reduced hardseededness. This review provides a mechanistic framework for unlocking Astragalus seed dormancy and accelerating the conservation, breeding, and medicinal utilization of this important genus. Full article

Seed longevity plays a crucial role in the persistence of plant populations, particularly in short-lived species inhabiting unpredictable environments. However, empirical data on long-term seed viability remain scarce, especially for rare and poorly known taxa. Astragalus contortuplicatus is a threatened annual species of periodically flooded habitats, characterized by sporadic occurrence and limited ecological knowledge; based on its annual life cycle and the temporal unpredictability of its habitat, its long-term population persistence is likely facilitated by persistent seed banks. In a previous study, we demonstrated that seeds of this species stored in herbarium collections can retain the ability to germinate for more than a century. Here, we reassess seed germination capacity after an additional 11.5–12 years of dry storage, using the same germination protocol, and analyse temporal changes based on repeated measurements of the same herbarium specimens. Germination data from 2014 and 2026 were evaluated using binomial models, and the relationship between seed age and germination capacity was examined using linear and non-linear approaches. Paired analyses revealed a significant overall decline in germination probability over time, although responses varied among specimens. Despite this decline, seeds from the oldest available sample (collected in 1883) still retained the ability to germinate, with 20% germination after approximately 142.5 years of storage. Across the full dataset, seed age had a significant negative effect on germination, and non-linear models provided a better fit than simple linear regression, indicating that the loss of germination capacity does not follow a strictly linear pattern. Our results confirm the exceptional longevity of seeds in this rare species while also demonstrating that germination capacity declines over time under continued dry storage. These findings are consistent with the ecological expectation that long-lived, dormant seeds may contribute to population persistence in unpredictable habitats, while underlining the potential of herbarium collections as valuable resources for the conservation and possible restoration of threatened plant species. Notably, seeds in the oldest sample retained the ability to germinate, emphasizing the exceptional longevity of seeds in this species. Full article

In dormant sunflower achenes, several structures—the pericarp, seed coat and embryo—contribute to the repression of germination. Achene dormancy varies widely among cultivated sunflower genotypes, and understanding its transmission to hybrid progeny is important both for hybrid seed production and for clarifying the role of these structures. This study examined the inheritance of dormancy in the F1 progeny, with particular emphasis on thermo-inhibition (inhibition of germination at warm temperatures). Reciprocal crosses were performed using three oilseed inbred lines with contrasting dormancy phenotypes. Germination of achenes, seeds, and embryos was tested at 10 and 30 °C at harvest and during postharvest, together with hormonal responses (abscisic acid, ethylene and gibberellins) and measurements of endogenous ABA levels. Results show that maternally inherited, pericarp-imposed thermo-inhibition depends on the dormancy level of the hybrid embryo, which follows a zygotic pattern with incomplete dominance. While embryo sensitivity to ABA related positively with thermo-inhibition, surprisingly, embryonic ABA content was inversely related to dormancy level across genotypes. These findings provide new insight into physiological control of achene dormancy in sunflower and contribute to improved breeding strategies for high-quality hybrid seed. Full article

Plants have developed several dormancy mechanisms essential for resilience in adverse environments. Understanding these mechanisms allows for the development of weed control strategies and enhances seedling production. This study aimed to investigate the anatomical and ecophysiological mechanisms associated with seed coat impermeability and physical dormancy in Mimosa camporum Benth. and other Amazonian Mimosa L. species, emphasizing their effects on water uptake, germination behavior, and ecological adaptation. For M. camporum, the imbibition curve, seed coat anatomy through scanning electron microscopy, and germination tests of seeds subjected to chemical scarification (H₂SO₄) were determined. Data from 25 Amazonian Mimosa species were compiled for ecological and physiological characterization, with subsequent Multiple Correspondence Analysis. Immersion in H₂SO₄ for 5 min is adequate to break dormancy in Mimosa camporum Benth. seeds. In Mimosa camporum Benth., sulfuric acid scarification effectively promoted water uptake and germination, demonstrating the close relationship between seed anatomy, imbibition behavior, and dormancy regulation. Physical dormancy in Amazonian Mimosa L. species is directly associated with seed coat impermeability, especially the presence of macrosclereids in the palisade layer. In the Amazon, the reproductive success and resilience of Mimosa L. species are related to the physical dormancy and desiccation tolerance of their seeds. Full article

Pre-harvest sprouting (PHS), the premature germination of grains on the mother plant, causes substantial yield loss and grain-quality deterioration in rice under humid conditions. Although seed dormancy and germination are largely controlled by hormonal balance, the transcriptional mechanisms linking hormone signaling with metabolic adaptation during PHS remain unclear. In this study, we investigated the roles of two ethylene-responsive factor transcription factors, OsERF1 and OsERF94, in rice PHS regulation using CRISPR/Cas9-mediated knockout lines, together with physiological, gene-expression, and metabolite analyses. The oserf1-KO mutant showed reduced seed dormancy and increased germination under PHS-inducing conditions, accompanied by altered expression of abscisic acid- and gibberellin-related genes. In contrast, the oserf94-KO mutant exhibited enhanced dormancy and reduced germination, with decreased expression of hypoxia-responsive fermentation genes and impaired carbohydrate mobilization, as indicated by reduced soluble sugar and ethanol accumulation and increased starch content. These results suggest that OsERF1 contributes primarily to hormone-mediated dormancy maintenance, whereas OsERF94 supports metabolic activation required for germination under high-moisture conditions. Collectively, this study proposes a dual regulatory framework in which hormonal control and hypoxia-associated carbon metabolism coordinately determine rice PHS susceptibility. Full article

Eryngium foetidum is classified as a Non-Conventional Food Plant (NCFP) with socioeconomic importance in the Amazon region, whose propagation is limited by low and irregular germination. This study aimed to evaluate methods for overcoming dormancy and promoting the germination of propagules of this species. Treatments consisted of chemical scarification with sulfuric acid (1, 2, and 3 min), mechanical scarification with sandpaper, soaking in water at room temperature, soaking in hot water, and an untreated control. Germination and seed vigor parameters were evaluated. Based on the analyses performed, chemical scarification treatments provided the best results, promoting higher germination and germination speed index, as well as a lower percentage of hard propagules and reduced mean germination time compared with the other treatments. Furthermore, the reduction in the number of hard propagules and their negative association with germination and vigor suggest the possible occurrence of physical dormancy in this species. Therefore, it can be concluded that chemical scarification with sulfuric acid is the most effective method for overcoming dormancy in Eryngium foetidum, contributing to the development of more efficient propagation protocols. Full article

Salvia przewalskii Maxim. is a perennial alpine plant with significant ornamental and medicinal value. However, previous studies have shown that this species has a low germination rate under natural conditions, and its artificial propagation techniques remain unclear. This study aimed to investigate the seed quality and the effects of various pre-sowing treatments (storage, chemical, physical, hormonal, combined) and soil substrates on S. przewalskii germination. The results indicated that S. przewalskii seeds demonstrated high viability (>85%) but exhibited high empty seed rate (45.32%) and physiological dormancy. Compared with the control (20%), dehydration (24.44%), demucilage + dehydration combination (35.56%), storage at 4 °C for 360 (53.33%) and 450 (54.29%) days, and GA₃ (44.44–55.56%) treatments significantly enhanced S. przewalskii germination percentages. Demucilage, H₂SO₄ and KNO₃ treatments had negative effects on seed germination, while 6-BA treatment did not significantly improve seed germination. Among tested soil substrates, S. przewalskii seeds pre-chilled for 450 days showed the highest germination rate (71.11%) and optimal seedling growth in peat:vermiculite (3:1), representing the most suitable soil substrate. These findings demonstrate that understanding germination characteristics of S. przewalskii is crucial for developing protocols to enhance germination efficiency that can improve large-scale propagation capacity through shorter germination periods, ultimately enhancing the species regeneration potential and protecting its stability in nature. Full article

Efficient seed regeneration of woody plants is of practical importance for horticulture and conservation practitioners. Seeds of the genus Viburnum are known to be difficult to germinate, as mechanisms of morphophysiological dormancy breaking can vary significantly among species, necessitating unique treatments to promote embryo growth and overcome physiological dormancy barriers. In this study, our objectives were (1) to characterize the class of seed dormancy for V. lantanoides, and (2) to optimize a protocol for seed-based regeneration for the species. Specifically, we evaluated warm and cold stratification treatments of increasing length and assessed the effectiveness and timing of seed germination. Results indicate that V. lantanoides seeds exhibit deep simple epicotyl morphophysiological dormancy (MPD), for which a sequence of warm–cold–warm temperatures is required to complete germination processes. We further assessed probability and time to emergence for radicles, cotyledons, and true leaves, and found that the combination of 12-week warm stratification followed by 12-week cold stratification resulted in the fastest and most effective method for seedling regeneration. This study represents an initial exploratory report on seed dormancy and regeneration in Viburnum section Pseudotinus and is intended to enhance physiological understanding of V. lantanoides seeds in support of conservation and horticultural efforts. Full article

Halophytes thrive in saline habitats through highly specialized adaptive responses, including seed-based strategies to regulate germination timing and ensure reproductive success under fluctuating environmental conditions. Salt-induced quiescence, structural alteration, and regulatory mechanisms are valuable adaptive strategies that facilitate plant growth under high saline conditions, which are becoming increasingly severe due to global climate change. This review provides an overview of the current understanding of halophyte seed germination, dormancy, and recovery. Low to moderate salt exposure generally causes reversible inhibition of germination; however, prolonged or high-level exposure causes stress-induced seed damage. On the other hand, halophyte seeds exhibit regulatory mechanisms associated with germination inhibition under high salt conditions. Adaptive traits such as seed heteromorphism, protective seed coats, mucilage production, and physiological dormancy enhance survival and establishment in saline soils. The ability of halophyte seeds to maintain viability under high salinity and to germinate rapidly when salt stress is alleviated indicates the preservation of metabolic and cellular integrity. Structural adaptations, regulatory mechanisms that balance germination, and the salt-induced quiescent process are controlled by morphological changes and molecular mechanisms. Furthermore, this review highlights the ecological significance and potential applications of halophyte seeds for crop improvement and the restoration of saline and degraded lands. Therefore, understanding the regulatory mechanisms of halophyte seed behavior is a valuable approach for enhancing plant resilience to salinity stress. Full article

Viola odorata, commonly known as sweet violet, is valued for both its fragrance and medicinal properties. However, seeds of V. odorata exhibit non-deep physiological dormancy, resulting in poor and inconsistent germination. This dormancy can be overcome through physical or chemical treatments, including scarification, stratification, and hormone application. Although mechanical scarification is effective, many commonly used approaches have notable limitations, such as reliance on corrosive chemicals and a lack of uniformity. This study presents a simple and effective mechanical scarification technique using rat-tooth tweezers to gently crack the seed coat tip of V. odorata ‘Empress Augusta’ (EA). This method significantly improved germination. When combined with cold stratification at 4 °C, germination further increased, reaching 70% within 8 weeks. Germination was enhanced even further on Murashige and Skoog (MS) basal salt medium supplemented with 10 mg/L gibberellic acid (GA₃), achieving 97.5% germination by day 54. These findings suggest that this simple mechanical scarification method, when combined with cold stratification and GA₃ treatment, could provide a reliable and practical strategy for breaking dormancy and facilitating seed germination in V. odorata. Full article

Seed germination is a critical determinant of seedling establishment, stress resistance, and final yield. ABA catabolism plays a central role in releasing seed dormancy and promoting germination, and ABA8ox is the key rate-limiting enzyme in this process. In this study, we used wild-type maize B73, and ZmABA8ox1b CRISPR-Cas9 knockout mutant as materials to investigate the biological function of ZmABA8ox1b. Compared with the wild type, the zmaba8ox1b mutant significantly delayed seed germination and enhanced the sensitivity to exogenous ABA. Endogenous ABA content in mutant embryos was drastically increased, indicating that ZmABA8ox1b is essential for ABA degradation during germination. The loss of ZmABA8ox1b function led to the activation of the ABA signaling pathway and severely impaired the responsiveness to exogenous ABA. Moreover, the mutation disturbed the expression and ABA responsiveness of auxin, gibberellin, ethylene, jasmonic acid, and brassinosteroid pathways, leading to a hormonal network imbalance. In conclusion, ZmABA8ox1b positively regulates maize seed germination by coordinating ABA catabolism and multi-hormone signal crosstalk. This study preliminarily clarifies the molecular mechanism of ZmABA8ox1b in germination control and provides important gene resources and theoretical support for breeding maize varieties. Full article