Search Results (70)

Seeds in soil are often exposed to cycles of hydration and dehydration, which can prime them by triggering physiological activation without leading to germination. While this phenomenon has been scarcely studied in wild species, it may play a critical role in enhancing drought resilience and maintaining seed viability under the warmer conditions predicted by climate change. In this study, I investigated the effects of hydration–dehydration cycles on germination response under water stress in eight Cistus species typical of Mediterranean shrublands. First, seeds were exposed to a heat shock to break physical dormancy, simulating fire conditions. Subsequently, they underwent one of two hydration–dehydration treatments (24 or 48 h) and were germinated under a range of water potentials (0, –0.2, –0.4, –0.6, and –0.8 MPa). Six out of eight species showed enhanced germination responses following hydration–dehydration treatments, including higher final germination percentages, earlier germination onset (T₀), or increased tolerance to water stress. These findings highlight the role of water availability as a key factor regulating germination in Cistus species and evidence a hydration memory mechanism that may contribute in different ways to post-fire regeneration in Mediterranean ecosystems. Full article

The hard-seed coat of Ormosia henryi significantly impedes germination efficiency in massive propagation, while conventional physical dormancy-breaking methods often result in compromised seed vigor, asynchronous seedling emergence, and diminished stress tolerance. Seed biopriming, an innovative technique involving the inoculation of beneficial microorganisms onto seed surfaces or into germination substrates, enhances germination kinetics and emergence uniformity through microbial metabolic functions and synergistic interactions with seed exudates. Notably, spermosphere-derived functional bacteria isolated from native spermosphere soil demonstrate superior colonization capacity and sustained bioactivity. This investigation employed selective inoculation of these indigenous functional strains to systematically analyze dynamic changes in endogenous phytohormones, enzymatic activities, and storage substances during critical germination phases, thereby elucidating the physiological mechanisms underlying biopriming-enhanced germination. The experimental results demonstrated significant improvements in germination parameters through biopriming. Inoculation with the Bacillus sp. strain achieved a peak germination rate (76.19%), representing a 16.19% increase over the control (p < 0.05). The biopriming treatment effectively improved the seed vigor, broke the impermeability of the seed coat, accelerated the germination speed, and positively regulated physiological indicators, especially amylase activity and the ratio of gibberellic acid to abscisic acid. This study establishes a theoretical framework for microbial chemotaxis and rhizocompetence in seed priming applications while providing an eco-technological solution for overcoming germination constraints in O. henryi cultivation. The optimized biopriming protocol addresses both low germination rates and post-germination growth limitations, providing technical support for the seedling cultivation of O. henryi. Full article

The genus Rhynchosia includes more than 550 species, some exhibiting invasive behavior. Rynchosia senna var. senna (RS) is a challenging weed to control in its native range; however, its invasive potential remains unknown. The aim of this study was to evaluate RS demographic parameters to determine its invasive potential, including (i) plant fecundity during the first year of young adult and in adult plants, (ii) seed dispersal, (iii) pre- and post-dispersal predation, (iv) soil seedbank persistence, and (v) field emergence patterns. RS fecundity declined in autumn and mainly in early established cohorts. Fecundity was influenced by pre-dispersal predation (Bruchus spp. 12 ± 2%), and post-dispersal removal by birds (66 ± 4%) and arthropods (37 ± 5%). Seed dispersal decreased with distance. Seedling emergence occurred mainly during early summer (75%), and to a lesser extent during late summer (20%) and autumn (5%). Seed physical dormancy loss (~80% in the first year) defines a short persistent seedbank. Under the evaluated conditions (native environment), RS shows a limited invasive potential. However, in non-native environments, in the absence of natural predators, its prolific fecundity and the occurrence of staggered emergence patterns could easily enhance invasiveness, enabling rapid colonization, as observed in Medicago polymorpha L. Full article

The effect of different treatments on the seed quality of crimson clover (Trifolium incarnatum L.) from six localities in eastern Serbia was investigated. The aim of this study was to improve seed quality and seedling growth of T. incarnatum using eco-friendly treatments. Tests were carried out under laboratory and field conditions, using hot water and air-drying temperatures. Seed quality parameters included germinated seeds, dormant seeds, dead seeds, seedling growth, and abnormal seedlings, all expressed as percentages. The water absorption test confirmed the presence of physical seed dormancy in crimson clover. The best results were achieved with a 30-min hot water treatment, which increased water absorption and reduced the percentage of dormant seeds. Longer exposure times increased the percentage of dead seeds and abnormal seedlings, whereas shorter exposure times increased the percentage of dormant seeds and reduced germination. There was strong agreement between the germination results obtained under laboratory and field conditions. These findings illustrate new biotechnological approaches to enhancing seed quality. Full article

Panax ginseng Meyer is one of the most popular traditional medicinal plants in Korea. Since ginseng seeds are morpho-physiologically dormant and have a very short lifespan, the harvested seeds need outdoor warm and cold stratification for 100 days each. The seeds were covered by a fruit coat (endocarp), which opened during warm stratification. Farmers must, therefore, dehisce (open the endocarp) seeds annually. The conditions for embryo growth, dehiscence percentage, and endocarp hardness were temperature, watering, stratification substances, solution scarification, and microbial inoculation of the seed endocarp. Watering, temperature (17.5 °C), and aeration are crucial for embryo growth as a germination condition. Moreover, microbial-mediated endocarp decomposition is necessary for dehiscence and embryonic development. This study suggests that a combination of embryo growth and microbial-mediated decomposition of the endocarp during warm stratification is a prerequisite for the dehiscence of ginseng seeds, implying physical and morpho-physiological dormancy. Any microbes (fungi, actinomycetes, and bacteria) tested with high or low cellulose-decomposing ability increased the dehiscence percentage by 66% compared to the untreated control. Seeds of three varieties of P. ginseng and one variety of P. quinquefolius were successfully dehisced by fungal inoculation of seeds. This approach opens the door for year-round indoor dehiscence of ginseng seeds without substrates, such as sand. Full article

Parrotia subaequalis, an endangered plant unique to China, is highly valued for its significant ecological and ornamental value. The specific type of seed dormancy in this species has not been clearly reported, which limits its natural regeneration and artificial propagation, posing a challenge to its conservation and sustainable use. To address this, we conducted a comprehensive analysis of the seed dormancy mechanism of P. subaequalis and explored various methods to break dormancy, including cold and warm stratification, after-ripening, seed coat removal, and hormone soaking. Our analysis of the seeds’ physical properties, water absorption patterns, seed coat structure, embryo development, and endogenous inhibitors revealed that P. subaequalis seeds exhibit complex characteristics of physical and non-deep physiological dormancy. Experimental results showed that soaking the seeds in gibberellin (GA₃) followed by seed coat removal effectively promoted germination. The optimal GA₃ concentration for germination was 800 mg·L⁻¹. Additionally, cold and warm stratification and after-ripening treatments significantly increased the germination percentage. These findings provide important technical support for dormancy release and seedling growth, which is crucial for the artificial propagation and population recovery of P. subaequalis. Full article

The preservation of biomasses through ensiling has a long history, and its sustainability has many aspects. One that is rarely considered is that the seeds of a wide variety of plants can enter the ensiling process with the plant biomass. This concise review provides an overview of the probability of seed survival in various types of silage since the 1930s. All data extracted from the reviewed studies are made available in a repository. The key finding from the 90 years of research is that ensiling can reduce the viability of plant seeds, but the seeds of some plant species can survive ensiling. Thus, silage production is both (1) a potential tool to ensure the sustainable, i.e., weed-free, use of plant biomass in agricultural production, including animal production chains, and (2) a potential gateway for weed spread, especially with regard to the closed material loops in circular bioeconomy approaches. The search for seed-borne factors and ensiling conditions that promote seed survival or killing is still ongoing and should be the subject of future research. Full article

Seed germination is a complex process involving imbibition, activation and subsequent growth. In addition to re-establishing metabolic activity, water uptake helps stabilize macromolecules and biochemical reactions, resulting in radicle protrusion. Factors affecting water uptake include seed composition, water availability and seed coat permeability. Water entry sites vary with species and occur primarily through the hilum, micropyle or lens. In addition, seed size influences water uptake, where larger seeds are usually less permeable. The seed coat plays a significant role in regulating the water absorption process. Several seed coat characteristics, including color, thickness and differences in the anatomical structure, such as the presence of pores, cuticles and radicle pockets, alter water permeability. Similarly, the presence of either physical or physiological seed dormancy negatively affects water uptake. This review emphasizes that understanding seed characteristics, such as size, shape and seed coat permeability, and their relationships is essential for breeding and selecting seeds with desirable traits, as they directly influence water uptake, leading to improved germination and growth. Full article

Mediterranean climates, characterised by hot and dry summers, have predictable fire regimes, and many species with physical seed dormancy (PY) thrive after wildfires. While it is well known that PY is released after heat shock in these species, intraspecific variation in seed response to heat is less understood. This research explores, for the first time, the variability in the traits of Cistus ladanifer seeds from the same central Spain population over eight years. It examines seed germination and viability under different heat shocks and the relationships among seed traits and climatic variables. While the response to heat shock remained constant over the years studied, achieving the highest germination percentages after heat shock at 100 °C, seed germination varied between years, and environmental conditions affected seed traits. Seed moisture content was negatively correlated with the maximum summer temperatures, and seed viability was positively related to annual precipitation. Germination at 100 °C was lower in warmer years as more seeds did not break their PY. In conclusion, despite the fact that PY appears to be genetically determined, it also depends on the environmental conditions experienced by the mother plant. This interannual phenotypic variability may help Cistus ladanifer to cope with the increasingly unpredictable conditions imposed by climate change. Full article

Onopordum nervosum subsp. platylepis Murb. is an Asteraceae species found in Tunisia, Algeria, and Libya. It has been studied for its potential use as a vegetable rennet alternative to animal-derived rennet, making it important to understand its germination characteristics. This species often shows low germinability due to dormancy, which limits its large-scale cultivation. In preliminary experiments, many factors were analyzed to evaluate the seed germination of this thistle including physical stratification with abrasive paper and high-temperature water, chemical treatments with hydrogen peroxide (H₂O₂) or sulfuric acid (H₂SO₄), and the exogenous use of the growth regulator gibberellic acid (GA₃). Based on the obtained results and subsequent analysis, GA₃ and cold stratification durations were selected for the second experiment, which used a full factorial RSM design with three levels for each factor. Additionally, the total polyphenol content (TPC), total flavonoid content (TFC), condensed tannin content (CTC), and DPPH assay were analyzed during the optimization process and for ungerminated seeds. The findings revealed that 14 days of cold stratification followed by 750 ppm GA₃ was the most efficient method for breaking the dormancy of these thistle seeds. The highest TPC was recorded in ungerminated seeds. However, germinated Onopordum nervosum ssp. platylepis seeds showed higher levels of TFC and CTC (14.83 mg QE/g DW and 6.49 mg EC/g DW, respectively) compared to the non-germinated ones and demonstrated the greatest potency in inhibiting free radicals (DPPH EC₅₀ = 0.018 mg/mL) at the identified optimal germination conditions. Ungerminated seeds indicated significant phenolic content (TPC) and a limited ability to reduce oxidants, which could explain their low germination percentage. Our findings on the seed germination and dormancy characteristics of this endemic thistle will aid in the protection and development of its germplasm. Full article

Schizanthus carlomunozii, S. hookeri, and S. porrigens are herbaceous species native to Chile and Argentina and have high ornamental potential. Their propagation through seeds is challenging due to low and uneven germination percentages. This study aimed to determine the morpho-anatomical characteristics, dormancy, and germination requirements of the seeds of these three species. The seeds from all three species have a flattened and reniform shape with a foveolate testa. However, the seeds of S. hookeri are distinguished by their larger size, more pronounced C-shape, seed coat with more marked prominences, and symmetrically arranged areoles. Histological analysis and imbibition tests with methylene blue revealed that the seeds have well-developed embryos and permeable seed coats, ruling out physical and morphological dormancy. Germination tests under various conditions showed that the seeds of the three species exhibit physiological dormancy. Imbibition in gibberellic acid (200 ppm) proved to be an effective treatment to promote germination. When evaluated in S. hookeri seeds, cold stratification and after-ripening also improved germination. The optimal temperatures for seed germination were calculated to be 26 °C for S. carlomunozii, 19 °C for S. hookeri, and 23 °C for S. porrigens. Full article

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. Full article

Physical dormancy of seeds is a form of dormancy due to the presence of an impermeable seed coat layer, and it represents a feature for plants to adapt to environmental changes over an extended period of phylogenetic evolution. However, in agricultural practice, physical dormancy is problematic. because it prevents timely and uniform seed germination. Therefore, physical dormancy is an important agronomical trait to target in breeding and domestication, especially for many leguminous crops. Compared to the well-characterized physiological dormancy, research progress on physical dormancy at the molecular level has been limited until recent years, due to the lack of suitable research materials. This review focuses on the structure of seed coat, factors affecting physical dormancy, genes controlling physical dormancy, and plants suitable for studying physical dormancy at the molecular level. Our goal is to provide a plethora of information for further molecular research on physical dormancy. Full article

Understanding the relationships between seed traits and germination responses is crucial for assessing natural regeneration, particularly in threatened ecosystems like the seasonally dry tropical forest (SDTF). This study explored links between seed traits (mass, volume, moisture content, and dispersal type), germination responses (germinability, germination speed ($\overline{v}$), time to 50% of germination (T50), synchrony, and photoblastism), and physical dormancy (PY) in 65 SDTF species under experimental laboratory conditions. We found that species with smaller seeds (low mass and volume) had higher $\overline{v}$ and reached T50 faster than species with larger seeds. For moisture content, species with lower moisture content had higher germinability and reached the T50 faster than seeds with high moisture content. Abiotic dispersed species germinated faster and reached the T50 in fewer days. Most of the SDTF species (60%) did not present PY, and the presence of PY was associated with seeds with lower moisture content. As for photoblastism (germination sensitivity to light), we classified the species into three ecological categories: generalists (42 species, non-photoblastic), heliophytes (18 species, positive photoblastic, germination inhibited by darkness), and sciadophytes (5 species, negative photoblastic, light inhibited germination). This study intends to be a baseline for the study of seed ecophysiology in the SDTF. Full article

The excavation and utilization of dormancy loci in breeding are effective endeavors for enhancing the resistance to pre-harvest sprouting (PHS) of wheat varieties. CH1539 is a wheat breeding line with high-level seed dormancy. To clarify the dormant loci carried by CH1539 and obtain linked molecular markers, in this study, a recombinant inbred line (RIL) population derived from the cross of weak dormant SY95-71 and strong dormant CH1539 was genotyped using the Wheat17K single-nucleotide polymorphism (SNP) array, and a high-density genetic map covering 21 chromosomes and consisting of 2437 SNP markers was constructed. Then, the germination percentage (GP) and germination index (GI) of the seeds from each RIL were estimated. Two QTLs for GP on chromosomes 5A and 6B, and four QTLs for GI on chromosomes 5A, 6B, 6D and 7A were identified. Among them, the QTL on chromosomes 6B controlling both GP and GI, temporarily named QGp/Gi.sxau-6B, is a major QTL for seed dormancy with the maximum phenotypic variance explained of 17.66~34.11%. One PCR-based diagnostic marker Ger6B-3 for QGp/Gi.sxau-6B was developed, and the genetic effect of QGp/Gi.sxau-6B on the RIL population and a set of wheat germplasm comprising 97 accessions was successfully confirmed. QGp/Gi.sxau-6B located in the 28.7~30.9 Mbp physical position is different from all the known dormancy loci on chromosomes 6B, and within the interval, there are 30 high-confidence annotated genes. Our results revealed a novel QTL QGp/Gi.sxau-6B whose CH1539 allele had a strong and broad effect on seed dormancy, which will be useful in further PHS-resistant wheat breeding. Full article