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Sonchus oleraceus L. is an invasive species that negatively affects the quality and yield of different crops. This research aimed to evaluate the physiological behavior of seeds from the weed S. oleraceus L., which were subjected to different treatments in three experiments. In experiment 1, different gibberellic acid (GA) concentrations were applied (0, 200, 400, and 600 mg L-1). In the second experiment, apical, basal, and apical-basal cut treatments were carried out on the seeds. In a third experiment, seeds were placed at different sowing depths (0.5, 1, 2, 5, and 10 cm) in peat as the substrate. The results indicated that GA at concentrations higher than 200 mg L-1 inhibited seed germination and, consequently, seedling growth. Germination was similar between the 200 mg L-1 GA treatment and the control, but germination occurred faster in the control. The apical-basal cut in the seeds generated the highest percentage of germination, the highest average speed of germination, and a significantly lower time of germination than the control; however, the longest shoot was observed in the seeds without a cut, and the longest root was detected in the seeds with the basal cut. Seedling emergence was affected by sowing depth, where it was significantly greater at 0.5, lesser at 2 cm, and, at greater depths, seedlings did not emerge. [ABSTRACT FROM AUTHOR]

Torreya grandis, a dioecious Taxaceae species of significant economic value in southeast China, presents challenges for natural pollination due to asynchronous maturation of its sex organs and low pollen vitality. In order to enhance fertilization success through artificial pollination of T. grandis, this study investigated the optimal conditions for in vitro pollen germination and pollen tube growth of T. grandis. The optimal in vitro growth medium was found to contain 29 mM sucrose, 0.8 mM H 3 BO 3 , 0.72 mM CaCl 2 , and 0.32 mM MgSO 4 , supplemented with 4 μM NAA, 2 μM GA 3 , and 5 μM 2,4-D at pH=5.6. Under these conditions, we achieved a maximum pollen germination ratio of 69.99 ± 5.17 % and a pollen tube length of 34.38 ± 6.04 µm after 6 days germination at 28°C. FM4-64 dye and Mitotracker Red staining revealed highly dynamics of vesicles and mitochondria during germination, which were accumulated at the tip of pollen tube and exhibited biphasic movement patterns. The total number, motion rate, and movement velocity of vesicles as well as mitochondria showed an initially increase followed by a gradual decrease pattern. The presence of sucrose in the medium significantly increased the dynamics and metabolic activity of both vesicles and mitochondria, which may relate with higher pollen germination ratio and faster pollen tube growth compared to sucrose-depleted conditions. Thus, these findings shed light on the physiological characteristics of Torreya pollen germination and provide scientific information for improving Torreya fruit yield through artificial pollination., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Dormancy in seeds is a key persistence mechanism for many flowering plants. Physically dormant (PY) seeds have water impermeable seed coats, and in fire-prone systems a common mechanism for dormancy release is fire-induced soil heating. However, the thermal thresholds innate to seeds with PY may be influenced by vegetation, climate, and fire regimes, varying substantially between populations of the same species. To investigate intraspecific variation of thermal thresholds in PY seeds, we sampled obligate seeding Acacia pulchella (Fabaceae) which produces PY seeds. Sampling was undertaken from 13 populations across a climate gradient of rainfall and temperature, and between two vegetation communities in fire-prone Mediterranean-type ecosystems of south-west Western Australia. To test a range of weather and fire-induced soil heating dormancy-break scenarios, we conducted dry heat shock experiments between 40 and 140 °C for 10 min and scored germination for 16 weeks. We created population-specific thermal performance curves and extracted the dormancy release temperature at which 50 % of the seeds had germinated (DRT 50 ), the optimum dormancy-breaking temperature to stimulate maximum germination (T 0 ), and the lethal temperature at which 50 % of the seeds were killed (LT 50 ). Generalised linear models were used to examine relationships between thermal thresholds and possible vegetation, climate, and fire regime drivers of intraspecific variation in seed traits. We found that thermal thresholds differed between vegetation communities, with thresholds consistently higher in forest-type ecosystems compared to open woodland, and the influence of climate varied significantly between the two communities. Seeds from Jarrah Forest populations had a DRT 50 16.0 °C higher, a T 0 9.7 °C higher, and LT 50 7.8 °C higher than seeds from Banksia woodlands. A high rate of non-dormancy was identified in one population that had lost fire in its system and displayed significant germination after both summer and fire-related temperatures. The PY thermal thresholds modelled here provide insight into the strong influence of variable soil heating as a function of vegetation and fuel dynamics in fire-prone environments. Our findings highlight the significant intraspecific variation for this species and suggest that fire-induced soil heating generated by vegetation characteristics may be an overlooked element of fire regimes shaping seed traits., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Plant quiescence and seed dormancy can be triggered by reduced oxygen availability. Under water, oxygen depletion caused by flooding can culminate in a quiescent state, which is a plant strategy for energy preservation and survival. In adult plants, a quiescent state can be activated by sugar starvation, leading to metabolic depression. In seeds, secondary dormancy can be activated by reduced oxygen availability, which creates an unfavourable state for germination. The physical dormancy of some seeds and buds includes barriers to external conditions, which indirectly results in hypoxia. The molecular processes that support seed dormancy and plant survival through quiescence under hypoxia include the N-degron pathway, which enables the modulation of ethylene-responsive factors of group VII and downstream targets. This oxygen- and nitric oxide-dependent mechanism interacts with phytohormone-related pathways to control growth., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

The amount of total polyphenol content (TPC) in the grain could provide insights into the conditions during maturation and might also serve as an indicator of the grain's ability to germinate in the malting process or as seeds in the field. Varieties with higher natural TPC content might exhibit better germination parameters both in the field and in the malt house. This study investigates the relationship between TPC and seed germination characteristics i.e. seed vigour in four spring barley varieties over two years, considering diverse environmental conditions and exposure to drought conditions. The evaluation of seed germination characteristics in barley, with a focus on the root length and average diameter under drought conditions (-0.5 MPa) and suboptimal temperature (10 °C), was conducted. Drought conditions were induced using polyethylene glycol (PEG 6000). After durations of seven and fourteen days, the germinated seeds from the Petri dishes were scanned and subjected to analysis using WinRHIZO software following the metrics: Len 7, Len 14 (root length after seven and fourteen days in cm) and AvgD 7, AvgD 14 (root diameter after seven and fourteen days in mm). The findings support our initial hypothesis, indicating a variety-specific relationship between seed germination characteristics and increased TPC, where higher germination parameters might be associated with elevated TPC levels in some barley varieties., (© 2024. The Author(s).)

Premise: Seed germination involves risk; post-germination conditions might not allow survival and reproduction. Variable, stressful environments favor seeds with germination that avoids risk (e.g., germination in conditions predicting success), spreads risk (e.g., dormancy), or escapes risk (e.g., rapid germination). Germination studies often investigate trait correlations with climate features linked to variation in post-germination reproductive success. Rarely are long-term records of population reproductive success available., Methods: Supported by demographic and climate monitoring, we analyzed germination in the California winter-annual Clarkia xantiana subsp. xantiana. Sowing seeds of 10 populations across controlled levels of water potential and temperature, we estimated temperature-specific base water potential for 20% germination, germination time weighted by water potential above base (hydrotime), and a dormancy index (frequency of viable, ungerminated seeds). Mixed-effects models analyzed responses to (1) temperature, (2) discrete variation in reproductive success (presence or absence of years with zero seed production by a population), and (3) climate covariates, mean winter precipitation and coefficient of variation (CV) of spring precipitation. For six populations, records enabled analysis with a continuous metric of variable reproduction, the CV of per-capita reproductive success., Results: Populations with more variable reproductive success had higher base water potential and dormancy. Higher base water potential and faster germination occurred at warmer experimental temperatures and in seeds of populations with wetter winters., Conclusions: Geographic variation in seed germination in this species suggests local adaptation to demographic risk and rainfall. High base water potential and dormancy may concentrate germination in years likely to allow reproduction, while spreading risk among years., (© 2024 Botanical Society of America.)

Poterium spinosum L. is a key plant species forming typical shrub communities, distributed across the Mediterranean eastern coasts. The conservation of P. spinosum is thus of the utmost importance, especially due to the ever-increasing environmental pressures like climate changes and habitat fragmentation. This study, in particular, investigated for the first time the germination variability of P. spinosum at intrapopulation level, by analysing the germination behavior of five different subpopulations growing along the coasts of Sicily. For a more exhaustive picture of the main drivers of biodiversity loss affecting the distributional area of P. spinosum, the trends of climate and land-cover changes were also studied over the periods 1931-2020 and 1958-2018, respectively. The results found significant intrapopulation variability in P. spinosum, whose germination parameters showed that fruits and seeds from distinct subpopulations respond differently to diverse temperatures. Seeds showed generally higher values of final germination percentage (FGP) compared to fruits, and at higher temperatures: the highest FGP in seeds was 70% at 20 °C, whereas in fruits was 58.2% at 15 °C. The environmental threats showed worrying trends across the study area: during 1931-2020, the average temperature increased by 1.5 °C, whereas the average rainfall declined from 710 to 650 mm. Similarly, in the period 1958-2018, the analysis of the CORINE land-cover changes showed a highly fragmented agricultural landscape, where natural areas were reduced to 2.5-5.0%. Germination variability at intrapopulation level should be considered as a fundamental adaptation strategy, which can increase the reproductive success of P. spinosum under climate and land-cover changes., (© 2024. The Author(s).)

The microhardness of individual morphological structures of the hard coat of the seed of Gleditsia triacanthos L. was measured. Measurements were made on the transverse and frontal planes. Based on the differences in the hardness of the two planes, the anisotropy of the seed coat was revealed. The entire seed coat has a special hardness which can be compared with the hardness of hardwood like oat wood. An interesting feature was the hardness of the endosperm, comparable to the hardness of the epidermis. Further study of the processes that occur in seeds during imbibition is based on the obtained data. Mathematical modeling methods are the most promising for these tasks; they will help to identify the points of fragility and the points of the greatest tension in the seed coat. These results will allow us to find the best ways to destroy the seed coat and to accelerate the germination. Research of physical properties of the seed coat is of practical importance in the fact that in the future it will allow reducing of the hard-seeding and increasing the germination of seeds. The obtained data allows us to represent the initial hardness of the seed coat.

Euphorbia resinifera O. Berg is a prickly, leafless and succulent, Moroccan endemic shrub. Field data indicate that the plant faces many challenges related to its natural regeneration and its gradual decline that can lead to a probability of extinction, at least in some areas. Successful seed germination and survival of E. resinifera seedlings during the dry period is one of the main obstacles encountered in establishing natural seedlings. With this in mind, 3080 seeds of two morphotypes of E. resinifera (M1 and M2) were harvested in the Atlas of Beni Mellal to study their germinative potential and determine suitable conditions for growth and development of the seedlings. In the laboratory, five temperatures (10 °, 15 °C, 18 °C, 25 °C, and 35 °C) and two photoperiods (12 h light/12 h dark and 24 h dark) were tested. Whereas in field research, two factors were considered: the availability of water and the type of substrate (clay, peat, and limestone). Results show a maximum germination rate of around 52% for M2 at 15 °C and 48% for M1 at 18 °C. The Monitoring of plant seedling establishment and growth revealed a high vulnerability to prolonged periods of drought. However, consolidated soil is more conducive to seedling establishment. For this species, it is therefore essential to conserve the habitat within the karst geosystem. Furthermore, the variability of this species' morphotypes and their growth form architecture shows a tendency to favor the dwarf, cushion-shaped morphotype, which is the most widespread in the study area.

Seed priming with biostimulant for soybean is a promising practice contributing positively to the physiological quality and vigor of seedlings, but there are little studies regarding protocols of bioinputs, such as Ascophyllum nodosum L. seaweed extract. We aimed to evaluate the effect of doses of A. nodosum macroalgae in seed priming and its impact on germination and seedling vigor of soybean. Seeds were subjected to priming with A. nodosum extract (ANE) at doses of 0, 1, 2, 3, 4, and 5 mL kg seed-1 during 15 min. Priming with ANE did not influence the first count and seed germination. Soybean seedlings from priming with 5 mL kg-1 ANE showed higher growth and shoot and root dry biomass. We observed increase 18% for shoot dry matter with priming of 5 mL kg-1 ANE compared to untreated seeds. The responses were variable for the emergence speed index in function ANE and did not influence the photochemical processes in photosystem II. Seed priming with ANE contributed in higher chlorophyll index. ANE showed a biostimulant effect on soybean seedlings, providing better growth and biomass characteristics, being promising in seed priming, but further studies are suggested in order to increase information regarding its use protocol for soybean.

Salinity limits the growth and productivity of crops, to reverse these effects, natural pigments with antioxidant bioactivity can be studied, such as turmeric (Curcuma longa L.) and paprika (Capsicum annum L.). Therefore, it aimed to evaluate turmeric and paprika as possible saline stress attenuators and biostimulants during germination and initial development of smooth lettuce seedlings. In the laboratory, the seeds were treated for 1 hour with a solution of paprika and turmeric at doses 0 (negative control), 1, 2, 3 and 4 g L-1, and placed on a substrate with saline solution of sodium chloride 4 g L-1 (-0,4 Mpa), and a positive control, composed of dry seeds arranged in a substrate moistened with distilled water. Physiological quality analysis were carried out, and for the dose that showed the best result (4 g L-1), the treated seeds were grown in a greenhouse, and received weekly applications via foliar with a 4 g L-1 solution for turmeric and paprika. After the crop cycle, morphometric analyzes were performed. The turmeric and paprika solutions were analyzed by High-Performance Liquid Chromatography (HPLC) to identify the presence of bioactive substances. The turmeric doses were not efficient in overcoming the effects of salinity on seeds and seedlings, which was attributed to the low solubility of turmeric in water. Paprika, although it did not provide the biostimulant effect, was efficient in attenuating the effects of excess salt, at a concentration of 4 g L-1, promoting increases in physiological quality. In HPLC, a very low signal response was noted in relation to samples composed of turmeric and paprika solutions, indicating a low percentage of soluble compounds, which compromises bioactivity, and leads to the need for further analyses using surfactants and/or other solvents with which there is greater affinity.

This experiment was carried out to provide a comprehensive insight into the protein activities involved in dormancy establishment in seeds of common cocklebur (Xanthium strumarium), an annual plant with two dimorphic seeds contained in one casing known as a burr. These consist of a smaller dormant seed and a larger non-dormant seed. The proteome profile was compared between developing dormant and non-dormant seeds of Xanthium strumarium at five consecutive stages including three, 10, 20, 30, and 45 days after burr emergence (stages 1 to 5). We identified 6524 proteins in total, and approximately 3.6% of these were differentially abundant proteins (DAPs) between the two seed types. Both seed types showed fundamental changes in developmental programs during the examined stages. More than 38% of all DAPs were observed at the first stage, supporting the importance of the early developmental stage in seed fate determination. The detected DAPs at stage 1 were mainly associated with the cell division phase, which showed a delay in the dormant seeds. Over-representation of proteins responsible for cell wall biosynthesis, cytokinesis, and seed development were detected for non-dormant seeds at the first stage, while dormancy-associated proteins showed less abundance. Stage 3 was the critical stage for switching processes toward seed maturation and abscisic acid (ABA) signaling. Interestingly, higher abundance proteins in the mature non-dormant seed were mainly involved in the facilitation of seed germination. Taken together, the temporal pattern of the accumulated proteins in developing dormant seeds demonstrated a delay in the initiation of active cell division, enriched response to ABA, and defects in seed maturation. Moreover, stored proteins in the mature dormant seed delay germination but not dormancy induction. Finally, our results suggest that dormancy may be established at a stage of seed development earlier than previously thought., (© 2024 Scandinavian Plant Physiology Society.)

In the realm of plant biology and agriculture, seed germination serves as a fundamental process with far-reaching implications for crop production and environmental health. This comprehensive review seeks to unravel the intricate web of interactions between some biotic stressors and seed germination, addressing the pertinent issue of how these stressors influence seed germination. Different chemicals produced by interacting plants (different parts), fungi, bacteria, or insects can either promote or inhibit seed germination. Releasing chemicals that modulate signaling pathways and cellular processes significantly disrupt essential cellular functions. This disruption leads to diverse germination outcomes, introducing additional layers of complexity to this regulatory landscape. The chemicals perturb enzyme activity and membrane integrity, imposing unique challenges on the germination process. Understanding the mechanisms- how allelochemicals, mycotoxins, or bacterial toxins affect seed germination or the modes of action holds promise for more sustainable agricultural practices, enhanced pest control, and improved environmental outcomes. In sum, this review contributes to a fundamental exposition of the pivotal role of biotic stressors in shaping the germination of seeds., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Reproductive isolation is one of the mechanisms of speciation. The two currently accepted subspecies of Parodia haselbergii (P. haselbergii subsp. haselbergii and P. haselbergii subsp. graessneri) were studied regarding flower traits, phenology, breeding systems and pollination. In addition, a principal component analysis with 18 floral characters and germination tests under controlled conditions were performed for both taxa. Pollination was studied in the field, in two localities of Southern Brazil. Pollinators were recorded through photos and film. Breeding system experiments were performed by applying controlled pollinations to plants excluded from pollinators. Both taxa mostly differ in asynchronous flowering periods, floral traits (including floral part measurements and nectar concentration) and pollinators. The flowers of both subspecies are functionally protogynous and perform remarkably long lifespans (≥ 15 days), both traits being novelties for Cactaceae. Whereas the reddish flowers of P. haselbergii subsp. haselbergii (nectar concentration: ca. 18%) are pollinated by hummingbirds of Thalurania glaucopis, the greenish flowers of P. haselbergii subsp. graessneri (nectar concentration: ca. 29%) are pollinated by Augochlora bees (Halictidae). Both subspecies are self-compatible, yet pollinator-dependent. The principal component analysis evidenced that both subspecies are separated, regarding flower traits. The seeds of both subspecies performed differently in the germination tests, but the best results were recovered at 20 °C and germination considerably decreased around 30 °C. In conclusion, all these results support that both taxa are in reproductive isolation, and can be treated as different species., (© 2024. The Author(s) under exclusive licence to The Botanical Society of Japan.)

Nanopriming, an advanced seed priming technology, is highly praised for its environmental friendliness, safety, and effectiveness in promoting sustainable agriculture. Studies have shown that nanopriming can enhance seed germination by stimulating the expression of aquaporins and increasing amylase production. By applying an appropriate concentration of nanoparticles, seeds can generate reactive oxygen species (ROS), enhance their antioxidant capacity, improve their response to oxidative stress, and enhance their tolerance to both biotic and abiotic stresses. This positive impact extends beyond the seed germination and seedling growth stages, persisting throughout the entire life cycle. This review offers a comprehensive overview of recent research progress in seed priming using various nanoparticles, while also addressing current challenges and future opportunities for sustainable agriculture., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Masson SAS.. All rights reserved.)

ANOVA-simultaneous component analysis (ASCA) was applied to short-wave infrared spectral fingerprints of 5 malting barley varieties collected using a hyperspectral imaging system to determine the effect of germination, the influence of time and the influence of barley by means of a full factorial experimental design. ASCA indicated that there was a significant (p < 0.0001) effect of the germination status, the germination time and interaction on the spectral data for all varieties. The biochemical and physiological modification of the samples were characterised by visualisation of the longitudinal scores obtained from simultaneous component analysis for the germination time factor. This resulted in the visualisation and explanation of biochemical change over the course of barley germination as a factor of time. The relevant loadings indicated a significant change to the proteome, lipid and starch structure as driven by the uptake of water over time. The ASCA model were extrapolated to include the effect of barley variety to the already mentioned germination status and germination time factors, resulting once again in all the effects being significant (p < 0.0001). Here it was shown that all the barley varieties are significantly different from one another pre- and post-modification, based on the molecular vibrations observed in the short wave-infrared (SWIR) spectra, suggesting that the detection of biotic stress factors, such as pre-harvest germination, also differ for each variety, by indicating that the germination profile of each barley variety varies as a function of germination time. Thus, also the malting performance, germinative energy and chemical profile of each barley variety tested will vary before, during and after imbibition and germination - indicating the importance of malting commercial barley malt true to variety. These results indicate that (SWIR) spectral imaging instrumentation can possibly be used to monitor controlled germination of barley grain. Due to the shown ability of SWIR spectral imaging to detect small biochemical changes over time of barley grain during germination., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Stefan Hayward reports financial support was provided by Anheuser-Busch Inc. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier B.V. All rights reserved.)

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 (GA 3 ) 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 GA 3 , 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., Competing Interests: Shuai Gong and Wenya Hao are employed by Sinochem Agriculture Holdings Co. Ltd., (© 2024 Song et al.)

Background and Aims: Some plants germinate their seeds enclosed by a pericarp, whereas others lack the outer packaging. As a maternal tissue, the pericarp might impart seeds with different germination strategies. Plants in a community with different flowering times might separately disperse and germinate their seeds; therefore, flowering time can be considered as one manifestation of maternal effects on the offspring. The mass of the seed is another important factor influencing germination and represents the intrinsic resource of the seed that supports germination. Using seeds from a species-rich alpine meadow located in the Hengduan Mountains of China, a global biodiversity hotspot, we aimed to illustrate whether and how the type of seed (with or without a pericarp) modulates the interaction of flowering time and seed mass with germination., Methods: Seeds were germinated in generally favourable conditions, and the speed of germination [estimated by mean germination time (MGT)] was calculated. We quantified the maternal conditions by separation of flowering time for 67 species in the meadow, of which 31 produced seeds with pericarps and 36 yielded seeds without pericarps. We also weighed 100 seeds of each species to assess their mass., Key Results: The MGT varied between the two types of seeds. For seeds with pericarps, MGT was associated with flowering time but not with seed mass. Plants with earlier flowering times in the meadow exhibited more rapid seed germination. For seeds without a pericarp, the MGT depended on seed mass, with smaller seeds germinating more rapidly than larger seeds., Conclusions: The distinct responses of germination to flowering time and seed mass observed in seeds with and without a pericarp suggest that germination strategies might be mother-reliant for seeds protected by pericarps but self-reliant for those without such protection. This new finding improves our understanding of seed germination by integrating ecologically mediated maternal conditions and inherent genetic properties., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

To gain a deeper understanding of the flowering pattern and reproductive characteristics of Epimedium sagittatum, to enrich the research on the flower development of E. sagittatum and its reproductive regulation, and to screen the methods suitable for the rapid detection of pollen viability of E. sagittatum and to promote its cross-breeding. The characteristics of its flower parts were observed, recorded and measured, and the pollen viability of E. sagittatumwas determined by five methods, including TTC staining, I 2 -KI staining, red ink staining, peroxidase method and in vitro germination method. The flowering process of E. sagittatum can be divided into five stages: calyx dehiscence, bract spathe, petal outgrowth, pollen dispersal, and pollination and withering. The results of I 2 -KI staining and peroxidase method were significantly higher than those of other methods; the in vitro germination method was intuitive and accurate, but the operation was complicated and time-consuming; the red ink staining method was easy to operate and had obvious staining effect, and the results were the closest to those of the in vitro germination method; and it was found that the pollen of E. sagittatum was not as effective as the in vitro germination method at the bud stamen stage, the flower stigma and the flower bud. It was also found that the pollen viability and germination rate of E. sagittatum pollen were higher in the three periods of bud spitting, petal adductor and pollen dispersal. Comparing the five methods, the red ink staining method was found to be a better method for the rapid detection of pollen viability; the best pollination periods of E. sagittatum were the bud stamen stage, petal adductor stage, and pollen dispersal stage of flowers at the peak of bloom. This study on the flowering and fruiting pattern of E. sagittatum, and the related mechanism of sexual reproduction, can be used as a reference for the next step of research on the breeding of E. sagittatum., (© 2024. The Author(s).)

The floral microenvironment impacts gametophyte viability and plant-pollinator interactions. Plants employ mechanisms to modify floral temperature, including thermogenesis, absorption of solar radiation, and evaporative cooling. Whether floral thermoregulation impacts reproductive fitness, and how floral morphological variation mediates thermoregulatory capacity are poorly understood. We measured temperature of the floral microenvironment in the field and tested for thermogenesis in the lab in early spring flowering Hexastylis arifolia (Aristolochiaceae). We evaluated whether thermoregulatory capacity was associated with floral morphological variation. Finally, we experimentally determined the thermal optimum and tolerance of pollen to assess whether thermoregulation may ameliorate thermal stress to pollen. Pollen germination was optimal near 21 °C, with a 50% tolerance breadth of ~18 °C. In laboratory conditions, flowers exhibited thermogenesis of 1.5-4.8 °C for short intervals within a conserved timeframe (08:00-09:00 h). In the field, temperature inside the floral tube often deviated from ambient - floral interiors were up to 4 °C above ambient when it was cold, but some fell nearly 10 °C below ambient during peak heat. Flowers with smaller openings were cooler and more thermally stable than those with larger openings during peak heat. Thermoregulation maintained a floral microenvironment within the thermal tolerance breadth of pollen. Results suggest that H. arifolia flowers have a stronger capacity to cool than to warm, and that narrower floral openings create a distinct floral microenvironment, enhancing floral cooling effects. While deviation of floral temperature from ambient conditions maintains a suitable environment for pollen and suggests an adaptive role of thermoregulation, we discuss adaptive and nonadaptive mechanisms underlying floral warming and cooling., (© 2024 The Authors. Plant Biology published by John Wiley & Sons Ltd on behalf of German Society for Plant Sciences, Royal Botanical Society of the Netherlands.)

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., (© 2024 The Ecological Society of America.)

Given their critical role in plant reproduction and survival, seeds demand meticulous regulatory mechanisms to effectively store and mobilize reserves. Within seeds, the condition of storage reserves heavily depends on environmental stimuli and hormonal activation. Unlike non-protein reserves that commonly employ dedicated regulatory proteins for signaling, proteinaceous reserves may show a unique form of 'self-regulation', amplifying efficiency and precision in this process. Proteins rely on stability to carry out their functions. However, in specific physiological contexts, particularly in seed germination, protein instability becomes essential, fulfilling roles from signaling to regulation. In this study, the elongation factor 1-alpha has been identified as a main proteinaceous reserve in Nicotiana tabacum L. seeds and showed peculiar changes in stability based on tested chemical and physical conditions. A detailed biochemical analysis followed these steps to enhance our understanding of these protein attributes. The protein varied its behavior under different conditions of pH, temperature, and salt concentration, exhibiting shifts within physiological ranges. Notably, distinct solubility transitions were observed, with the elongation factor 1-alpha becoming insoluble upon reaching specific thresholds determined by the tested chemical and physical conditions. The findings are discussed within the context of seed signaling in response to environmental conditions during the key transitions of dormancy and germination., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Global climate change has already brought noticeable alterations to multiple regions of our planet, including increased CO2 concentrations and changes in temperature. Several important steps of plant growth and development, such as embryogenesis, can be affected by such environmental changes; for instance, they affect how stored nutrients are used during early stages of seed germination during the transition from heterotrophic to autotrophic metabolism-a critical period for the seedling's survival. In this article, we briefly describe relevant processes that occur during embryo maturation and account for nutrient accumulation, which are sensitive to environmental change. Most of the nutrients stored in the seed during its development-including carbohydrates, lipids, and proteins, depending on the species-accumulate during the seed maturation stage. It is also known that iron, a key micronutrient for various electron transfer processes in plant cells, accumulates during embryo maturation. The existing literature indicates that climate change can not only affect the quality of the seed, in terms of total nutritional content, but also affect seed production. We discuss the potential effects of temperature and CO2 increases from an embryo-autonomous point of view, in an attempt to separate the effects on the parent plant from those on the embryo., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

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., Competing Interests: Conflict of interest statement. None declared., (© The Author(s) 2024. Published by Oxford University Press on behalf of American Society of Plant Biologists.)

The pollen viability directly affects the pollination process and the ultimate grain yield of rice. Here, we identified that the MORN motif-containing proteins, OsMORN1 and OsMORN2, had a crucial role in maintaining pollen fertility. Compared with the wild type (WT), the pollen viability of the osmorn1 and osmorn2 mutants was reduced, and pollen germination was abnormal, resulting in significantly lower spikelet fertility, seed-setting rate, and grain yield per plant. Further investigation revealed that OsMORN1 was localized to the Golgi apparatus and lipid droplets. Lipids associated with pollen viability underwent alterations in osmorn mutants, such as the diacylglyceride (18:3&#95;18:3) was 5.1-fold higher and digalactosyldiacylglycerol (18:2&#95;18:2) was 5.2-fold lower in osmorn1, while the triacylglycerol (TG) (16:0&#95;18:2&#95;18:3) was 8.3-fold higher and TG (16:0&#95;18:1&#95;18:3) was 8.5-fold lower in osmorn2 than those in WT. Furthermore, the OsMORN1/2 was found to be associated with rice cold tolerance, as osmorn1 and osmorn2 mutants were more sensitive to chilling stress than WT. The mutants displayed increased hydrogen peroxide accumulation, reduced antioxidant enzyme activities, elevated malondialdehyde content, and a significantly decreased seedling survival rate. Lipidomics analysis revealed distinct alterations in lipids under low temperature, highlighting significant changes in TG (18:2&#95;18:3&#95;18:3) and TG (18:4&#95;18:2&#95;18:2) in osmorn1, TG (16:0&#95;18:2&#95;18:2) and PI (17:2&#95;18:3) in osmorn2 compared to the WT. Therefore, it suggested that OsMORN1 and OsMORN2 regulate both pollen viability and cold tolerance through maintaining lipid homeostasis., (© 2024 Society for Experimental Biology and John Wiley & Sons Ltd.)

To germinate in nature, orchid seeds strictly rely on seed germination-promoting orchid mycorrhizal fungi (sgOMFs) for provision of carbon nutrients. The underlying delivery pathway, however, remains elusive. We develop here a plausible model for sugar transport from sgOMFs to orchid embryonic cells to fuel germination. Orchids exploit sgOMFs to induce the formation of pelotons, elaborate intracellular hyphal coils in orchid embryos. The colonized orchid cells then obtain carbon nutrients by uptake from living hyphae and peloton lysis, primarily as glucose derived from fungal trehalose hydrolyzed by orchid-specific trehalases. The uptake of massive fungally derived glucose is likely to be mediated by two classes of membrane proteins, namely, sugars will eventually be exported transporters (SWEETs) and H + -hexose symporters. The proposed model serves as a launch pad for further research to better understand and improve orchid seed germination and conservation., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

The survival and growth of young plants hinge on various factors, such as seed quality and environmental conditions. Assessing seedling potential/vigor for a robust crop yield is crucial but often resource-intensive. This study explores cost-effective imaging techniques for rapid evaluation of seedling vigor, offering a practical solution to a common problem in agricultural research. In the first phase, nine lettuce ( Lactuca sativa ) cultivars were sown in trays and monitored using chlorophyll fluorescence imaging thrice weekly for two weeks. The second phase involved integrating embedded computers equipped with cameras for phenotyping. These systems captured and analyzed images four times daily, covering the entire growth cycle from seeding to harvest for four specific cultivars. All resulting data were promptly uploaded to the cloud, allowing for remote access and providing real-time information on plant performance. Results consistently showed the 'Muir' cultivar to have a larger canopy size and better germination, though 'Sparx' and 'Crispino' surpassed it in final dry weight. A non-linear model accurately predicted lettuce plant weight using seedling canopy size in the first study. The second study improved prediction accuracy with a sigmoidal growth curve from multiple harvests ( R 2 = 0.88, RMSE = 0.27, p < 0.001). Utilizing embedded computers in controlled environments offers efficient plant monitoring, provided there is a uniform canopy structure and minimal plant overlap.

Salinity stress is a common challenge in plant growth, impacting seed quality, germination, and general plant health. Sodium chloride (NaCl) ions disrupt membranes, causing ion leakage and reducing seed viability. Gibberellic acid (GA 3 ) treatments have been found to promote germination and mitigate salinity stress on germination and plant growth. 'Bauer' and 'Muir' lettuce ( Lactuca sativa ) seeds were soaked in distilled water (control), 100 mM NaCl, 100 mM NaCl + 50 mg/L GA 3 , and 100 mM NaCl + 150 mg/L GA 3 in Petri dishes and kept in a dark growth chamber at 25 °C for 24 h. After germination, seedlings were monitored using embedded cameras, capturing red, green, and blue (RGB) images from seeding to final harvest. Despite consistent germination rates, 'Bauer' seeds treated with NaCl showed reduced germination. Surprisingly, the 'Muir' cultivar's final dry weight differed across treatments, with the NaCl and high GA 3 concentration combination yielding the poorest results ( p < 0.05). This study highlights the efficacy of GA 3 applications in improving germination rates. However, at elevated concentrations, it induced excessive hypocotyl elongation and pale seedlings, posing challenges for two-dimensional imaging. Nonetheless, a sigmoidal regression model using projected canopy size accurately predicted dry weight across growth stages and cultivars, emphasizing its reliability despite treatment variations ( R 2 = 0.96, RMSE = 0.11, p < 0.001).

The decline in seed quality over time due to natural aging or mishandling requires assessing seed vigor for resilience in adverse conditions. Accelerated aging (AA) methods simulate seed deterioration by subjecting seeds to high temperatures and humidity. Saturated salt accelerated aging (SSAA) is an AA method adopted for small seeds like lettuce ( Lactuca sativa ). In this study, we subjected seeds of two lettuce cultivars ('Muir' and 'Bauer') to SSAA by sealing them in a box containing 40 g/100 mL of a sodium chloride (NaCl) solution in a dark growth chamber at 41 °C for 24, 48, and 72 h with a control. We monitored their vigor using embedded computer cameras, tracking the projected canopy size (PCS) daily from sowing to harvest. The cultivar 'Muir' exhibited consistent PCS values across the treatments, while 'Bauer' showed PCS variations, with notable declines after prolonged aging. The germination rates dropped significantly after 48 and 72 h of SSAA. A nonlinear regression model revealed a strong relationship between PCS and shoot dry weight across harvests and cultivars ( R 2 = 0.93, RMSE = 0.15, p < 0.001). The research found that the projected canopy size and shoot dry weight increased over time with significant differences in treatments for the cultivar 'Bauer' but not for 'Muir,' with the canopy size being a strong predictor of dry weight and no significant impact from the SSAA treatments. This study highlights cultivar-specific responses to aging and demonstrates the efficacy of our imaging tool in predicting lettuce dry weight despite treatment variations. Understanding how aging affects different lettuce varieties is crucial for seed management and crop sustainability.

Flowering plants rely on the polarized growth of pollen tubes to deliver sperm cells (SCs) to the embryo sac for double fertilization. In pollen, the vegetative nucleus (VN) and two SCs form the male germ unit (MGU). However, the mechanism underlying directional transportation of MGU is not well understood. In this study, we provide the first full picture of the dynamic interplay among microtubules, actin filaments, and MGU during pollen germination and tube growth. Depolymerization of microtubules and inhibition of kinesin activity result in an increased velocity and magnified amplitude of VN's forward and backward movement. Pharmacological washout experiments further suggest that microtubules participate in coordinating the directional movement of MGU. In contrast, suppression of the actomyosin system leads to a reduced velocity of VN mobility but without a moving pattern change. Moreover, detailed observation shows that the direction and velocity of VN's movement are in close correlations with those of the actomyosin-driven cytoplasmic streaming surrounding VN. Therefore, we propose that while actomyosin-based cytoplasmic streaming influences on the oscillational movement of MGU, microtubules and kinesins avoid MGU drifting with the cytoplasmic streaming and act as the major regulator for fine-tuning the proper positioning and directional migration of MGU in pollen., (© 2024. The Author(s).)

Background and Aims: Seed heteromorphism is a plant strategy that an individual plant produces two or more distinct types of diaspores, which have diverse morphology, dispersal ability, ecological functions and different effects on plant life history traits. The aim of this study was to test the effects of seasonal soil salinity and burial depth on the dynamics of dormancy/germination and persistence/depletion of buried trimorphic diaspores of a desert annual halophyte Atriplex centralasiatica., Methods: We investigated the effects of salinity and seasonal fluctuations of temperature on germination, recovery of germination and mortality of types A, B, C diaspores of A. centralasiatica in the laboratory and buried diaspores in situ at four soil salinities and three depths. Diaspores were collected monthly from the seedbank from December 2016 to November 2018, and the number of viable diaspores remaining (not depleted) and their germinability were determined., Results: Non-dormant type A diaspores were depleted in the low salinity "window" in the first year. Dormant diaspore types B and C germinated to high percentages at 0.3 and 0.1 mol L -1 soil salinity, respectively. High salinity and shallow burial delayed depletion of diaspore types B and C. High salinity delayed depletion time of the three diaspore types and delayed dormancy release of types B and C diaspores from autumn to spring. Soil salinity modified the response of diaspores in the seedbank by delaying seed dormancy release in autum and winter and by providing a low-salt concentration window for germination of non-dormant diaspores in spring and early summer., Conclusions: Buried trimorphic diaspores of annual desert halophyte A. centralasiatica exhibited diverse dormancy/germination behavior in respond to seasonal soil salinity fluctuation. Prolonging persistence of the seedbank and delaying depletion of diaspores under salt stress in situ primarily is due to inhibition of dormancy-break. The differences in dormancy/germination and seed persistence in the soil seedbank may be a bet-hadging strategy adapted to stressful temporal and spatial heterogeneity, and allows A. centralasiatica to persist in the unpredictable cold desert enevironment., (© 2024. The Author(s).)

One of the major limitations to proper weed management is the lack of knowledge about the biology of the species. The aim of this study was to understand the influence of temperature and light on the germination and emergence of Commelina benghalensis and Richardia brasiliensis, as well as the influence of burial depth in the soil and the presence of mulch. The experiment regarding the influence of light and temperature on germination was conducted using a 2x4 factorial design, with two light conditions (presence for 12 hours and absence for 24 hours) and four temperature alternations every 12 hours (20-25 ºC, 20-30 ºC, 20-35 ºC, and 15-35 ºC), with four replications. The second experiment was conducted in a completely randomized design with four replications, testing seven sowing depths (0.0; 0.5; 1.0; 2.0; 4.0; 6.0; 10.0 cm) in clay-textured soil. In the third experiment, millet, black oat, and sun hemp straw were placed on the surface of the pot where the weeds were sown. R. brasiliensis showed high germination rates at 15°-35°C and in the presence of light, indicating positive photoblastism, as the germination percentage was 63.50% in the presence of light and 1% without light. C. benghalensis showed higher germination rates at 20-35ºC, with a germination percentage of 46.5% under light treatment and 44% in the absence of light. R. brasiliensis exhibited the highest germination percentage at a depth of 0.5 cm, with 72.50%. C. benghalensis showed better germination at depths of 1 and 4 cm, with 48.33% and 49.16%, respectively. Both crotalaria and millet caused significant inhibition of germination in both weed species. R. brasiliensis and C. benghalensis exhibit higher seed germination under alternating temperatures, with R. brasiliensis displaying positive photoblastism and C. benghalensis being neutral. Greater seeding depths negatively influence germination, and cover crops such as crotalaria and millet can be used to suppress these weeds.

Background: Seed aging, a natural and inevitable process occurring during storage. Oats, an annual herb belonging to the Gramineae family and pooideae. In addition to being a healthy food, oats serve as ecological pastures, combating soil salinization and desertification. They also play a role in promoting grassland agriculture and supplementing winter livestock feed. However, the high lipid and fat derivatives contents of oat seeds make them susceptible to deterioration, as fat derivatives are prone to rancidity, affecting oat seed production, storage, development, and germplasm resource utilization. Comparative studies on the effects of aging on physiology and cytological structure in covered and naked oat seeds are limited. Thus, our study aimed to determine the mechanism underlying seed deterioration in artificially aged 'LongYan No. 3' (A. sativa) and 'BaiYan No. 2' (A. nuda) seeds, providing a basis for the physiological evaluation of oat seed aging and serving as a reference for scientifically safe storage and efficient utilization of oats., Results: In both oat varieties, superoxide dismutase and catalase activities in seeds showed increasing and decreasing trends, respectively. Variance analysis revealed significant differences and interaction in all measured indicators of oat seeds between the two varieties at different aging times. 'LongYan No. 3' seeds, aged for 24-96 h, exhibited a germination rate of < 30%, Conductivity, malondialdehyde, soluble sugar, and soluble protein levels increased more significantly than the 'BaiYan No. 2'. With prolonged aging leading to cell membrane degradation, reactive oxygen species accumulation, disrupted antioxidant enzyme system, evident embryo cell swelling, and disordered cell arrangement, blocking the nutrient supply route. Simultaneously, severely concentrated chromatin in the nucleus, damaged mitochondrial structure, and impaired energy metabolism were noted, resulting in the loss of 'LongYan No. 3' seed vitality and value. Conversely, 'BaiYan No. 2' seeds showed a germination rate of 73.33% after 96 h of aging, consistently higher antioxidant enzyme activity during aging, normal embryonic cell shape, and existence of the endoplasmic reticulum., Conclusions: ROS accumulation and antioxidant enzyme system damage in aged oat seeds, nuclear chromatin condensation, mitochondrial structure damage, nucleic acid metabolism and respiration weakened, oat seed vigor decreased. 'LongYan No. 3' seeds were more severely damaged under artificial aging than 'BaiYan No. 2' seeds, highlighting their heightened susceptibility to aging effects., (© 2024. The Author(s).)

Several herbaceous species exhibit mass flowering after fires in Neotropical savannas. However, unequivocal evidence of fire dependency and the consequences for plant reproduction are lacking. In nutrient-poor fire-prone savannas, the damage caused by fire and by other means (e.g., leaf removal, but not necessarily having a negative impact) constrains the maintenance and expansion of plant population by affecting the ability of individuals to recover. Therefore, the compensatory responses of plants to both damages should be convergent in such environments. Using Bulbostylis paradoxa-reported to be fire-dependent to flower-as a model, we investigated the role of fire and leaf removal in anticipating the flowering and reproduction periods, and its possible consequences on seedling establishment. We monitored 70 burned individuals, 70 damaged/clipped, and 35 without damage to estimate time for flowering, seed quality and germination parameters. To expand our sampling coverage, we examined high-resolution images from herbarium collections in the SpeciesLink database. For each herbarium image, we recorded the presence or absence of a fire scar, the month of flowering, and the number of flowering stalks. Bulbostylis paradoxa was fire-stimulated but not dependent on fire to flower, with 65.7% of the individuals flowering in the burned area, 48.6% in the clipped, and 11.4% in the control. This was consistent with the analysis of the herbarium images in which 85.7% of the specimens with flowers had fire scars and 14.3% did not. Burned individuals synchronized flowering and produced more viable seeds. However, the seeds might face a period of unsuitable ecological conditions after early to mid-dry season fires. Flowering of unburned plants was synchronized with the onset of the rainy season. Flexibility in flowering and vegetative reproduction by fragmentation confer to this species, and most likely other plants from the herbaceous layer, the capability of site occupation and population persistence in burned and unburned savanna sites., Competing Interests: NO authors have competing interests., (Copyright: © 2024 Miranda et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Background: Lentil is a significant legume that are consumed as a staple food and have a significant economic impact around the world. The purpose of the present research on lentil was to assess the hydrothermal time model's capacity to explain the dynamics of Lens culinaris L. var. Markaz-09 seed germination, as well as to ascertain the germination responses at various sub-optimal temperatures (T) and water potentials (Ψ). In order to study lentil seed germination (SG) behavior at variable water potentials (Ψs) and temperatures (Ts). A lab experiment employing the hydrothermal time model was created. Seeds were germinated at six distinct temperatures: 15 0 С, 20 0 С, 25 0 С, 30 0 С, 35 0 С, and 40 0 С, with five Ψs of 0, -0.3, -0.6, -0.9, and - 1.2 MPa in a PEG-6000 (Polyethylene glycol 6000) solution., Results: The results indicated that the agronomic parameters like Germination index (GI), Germination energy (GE), Timson germination index (TGI), were maximum in 25 0 C at (-0.9 MPa) and lowest at 40 0 C in 0 MPa. On other hand, mean germination time (MGT) value was highest at 15 0 C in -1.2 MPa and minimum at 40 0 C in (-0.6 MPa) while Mean germination rate (MGR) was maximum at 40 0 C in (0 MPa) and minimum at 15 0 C in (-0.6 MPa)., Conclusions: The HTT model eventually defined the germination response of Lens culinaris L. var. Markaz-09 (Lentil) for all Ts and Ψs, allowing it to be employed as a predictive tool in Lens culinaris L. var. Markaz-09 (Lentil) seed germination simulation models., (© 2024. The Author(s).)

Arthraxon hispidus is an introduced, rapidly spreading, and newly invasive grass in the eastern United States, yet little is known about the foundational biology of this aggressive invader. Germination responses to environmental factors including salinity, pH, osmotic potential, temperature, and burial depth were investigated to better understand its germination niche. Seeds from six populations in the Mid-Atlantic US germinated 95% with an average mean time to germination of 3.42 days of imbibition in the dark at 23°C. Germination occurred across a temperature range of 8-37°C and a pH range of 5-10 (≥83%), suggesting that neither pH nor temperature will limit germination in many environments. Arthraxon hispidus germination occurred in high salinity (342 mM NaCl) and osmotic potentials as low as -0.83MPa. The NaCl concentration required to reduce germination by 50% exceeded salinity concentrations found in soil and some brackish water saltmarsh systems. While drought adversely affects A. hispidus, 50% germination occurred at osmotic potentials ranging from -0.25 to -0.67 MPa. Given the climatic conditions of North America, drought stress is unlikely to restrict germination in large regions. Finally, emergence greatly decreased with burial depth. Emergence was reduced to 45% at 1-2 cm burial depths, and 0% at 8 cm. Emergence depths in concert with adequate moisture, germination across a range of temperatures, and rapid germination suggests A. hispidus' seed bank may be short-lived in moist environments, but further investigation is warranted. Given the broad abiotic tolerances of A. hispidus and a widespread native range, A. hispidus has the potential to germinate in novel territories beyond its currently observed invaded range., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Beall et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

The ability to germinate, develop, and thrive underwater is key to efficient rice cultivation. In this issue of Developmental Cell, Wang et al. (2024) illuminate a hormone synthesis and inactivation cascade that promotes germination of submerged rice seeds and may allow improved germination in the field., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2024 Elsevier Inc. All rights reserved.)

The mechanism underlying the ability of rice to germinate underwater is a largely enigmatic but key research question highly relevant to rice cultivation. Moreover, although rice is known to accumulate salicylic acid (SA), SA biosynthesis is poorly defined, and its role in underwater germination is unknown. It is also unclear whether peroxisomes, organelles essential to oilseed germination and rice SA accumulation, play a role in rice germination. Here, we show that submerged imbibition of rice seeds induces SA accumulation to promote germination in submergence. Two submergence-induced peroxisomal Oryza sativa cinnamate:CoA ligases (OsCNLs) are required for this SA accumulation. SA exerts this germination-promoting function by inducing indole-acetic acid (IAA) catabolism through the IAA-amino acid conjugating enzyme GH3. The metabolic cascade we identified may potentially be adopted in agriculture to improve the underwater germination of submergence-intolerant rice varieties. SA pretreatment is also a promising strategy to improve submerged rice germination in the field., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2024 Elsevier Inc. All rights reserved.)

To facilitate the study of learning in plants, we share our experiences of trying to replicate the pea plant experiment of Gagliano et al. In the course of our efforts, we identified 11 issues that must be addressed when attempting to replicate these experiments. The issues range from germination and transplantation of seedlings to experimental design and apparatus issues. We propose a number of solutions to overcome these hurdles., Competing Interests: Declaration of conflicting interestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Background: Horsfieldia hainanensis Merr., an indicator species of China's humid tropical rainforests, is endangered due to difficulties with population regeneration. In this study, the biological characteristics and germination adaptability of the seeds were studied for the first time, in order to provide a basis for analyzing the causes of endangerment and strategies for the artificial cultivation of H. hainanensis. The effects of biological characteristics (population, arils, seed coat, seed weight, seed moisture content) and environmental factors (temperature, light, drought, substrate, burial depth) on seed germination and seedling growth of H. hainanensis were studied., Results and Discussion: The fruits were found to be capsules containing seeds wrapped in a pericarp and fleshy aril, which provide protection and assist in seed dispersal, but also pose risks to the seeds, as the peel and fleshy aril can become moldy under high temperature and humidity conditions. There were significant differences in fruit morphology and germination characteristics among different populations, and the seed quality of populations in Niandian village, Daxin County, Chongzuo City, Guangxi Zhuang Autonomous Region was better. The arils significantly inhibited seed germination, the germination of large seeds was better, and seedling growth from medium seeds was superior. H. hainanensis seeds were sensitive to dehydration, and intolerant to drought and low temperature, which is typical of recalcitrant seeds. The seeds are suitable for germination on a moist substrate surface with good water retention and breathability at 30-35℃., (© 2024. The Author(s).)

Agricultural management using technologies that help farmers increase productivity and reduce production costs must be promoted to ensure agricultural sustainability. The objective of the study was to achieve the pH effect of growth solution, chemical treatment, use of osmoprotector additive and mineral nitrate presence, on the activity of growth promoting bacteria, Azospirillum brasilense, and its effects on the physiological quality of seeds and wheat seedling growth. The first experiment evaluated the physiological quality of seeds and the second experiment was divided into four, evaluating the growth of wheat seedling in a hydroponic system. The experiments were prolonged in a very randomized design, with four replications. The physiological quality of the seeds was evaluated by germination tests, first germination count, length of the shoot and root and dry mass of the shoot and root. Initial growth was evaluated by quantifying the dry mass of the leaf shoot and root and the root system intervals. The pH of the solution and the presence of nitrogen did not influence the effects of inoculation of the A. brasilense bacteria. With the use of chemical treatment and osmoprotective additive, A. brasilense had no effect on the growth of wheat seedlings.

Cold stratification is known to affect the speed of seed germination; however, its regulation at the molecular level in Ferula assa-foetida remains ambiguous. Here, we used cold stratification (4 °C in the dark) to induce germination in F. assa-foetida and adopted a proteomic and metabolomic approach to understand the molecular mechanism of germination. Compared to the control, we identified 209 non-redundant proteins and 96 metabolites in germinated F. assa-foetida seed. Results highlight the common and unique regulatory mechanisms like signaling cascade, reactivation of energy metabolism, activation of ROS scavenging system, DNA repair, gene expression cascade, cytoskeleton, and cell wall modulation in F. assa-foetida germination. A protein-protein interaction network identifies 18 hub protein species central to the interactome and could be a key player in F. assa-foetida germination. Further, the predominant metabolic pathways like glucosinolate biosynthesis, arginine and proline metabolism, cysteine and methionine metabolism, aminoacyl-tRNA biosynthesis, and carotenoid biosynthesis in germinating seed may indicate the regulation of carbon and nitrogen metabolism is prime essential to maintain the physiology of germinating seedlings. The findings of this study provide a better understanding of cold stratification-induced seed germination, which might be utilized for genetic modification and traditional breeding of Ferula assa-foetida. SIGNIFICANCE: Seed germination is the fundamental checkpoint for plant growth and development, which has ecological significance. Ferula assa-foetida L., commonly known as "asafoetida," is a medicinal and food crop with huge therapeutic potential. To date, our understanding of F. assa-foetida seed germination is rudimentary. Therefore, studying the molecular mechanism that governs dormancy decay and the onset of germination in F. assa-foetida is essential for understanding the basic principle of seed germination, which could offer to improve genetic modification and traditional breeding., Competing Interests: Declaration of competing interest The authors declare no conflict of interest., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Background and Aims: Orchid seeds are reputed to be short lived in dry, cold storage conditions, potentially limiting the use of conventional seed banks for long-term ex situ conservation. This work explores whether Cattleya seeds are long lived or not during conventional storage (predried to ~12 % relative humidity, then stored at -18 °C)., Methods: We explored the possible interaction of factors influencing seed lifespan in eight species of the genus Cattleya using physiological (germination and vigour), biochemical (gas chromatography), biophysical (differential scanning calorimetry) and morphometric methods. Seeds were desiccated to ~3 % moisture content and stored at -18 °C for more than a decade, and seed quality was measured via three in vitro germination techniques. Tetrazolium staining was also used to monitor seed viability during storage. The morphometric and germination data were subjected to ANOVA and cluster analysis, and seed lifespan was subjected to probit analysis., Key Results: Seeds of all Cattleya species were found to be desiccation tolerant, with predicted storage lifespans (P50y) of ~30 years for six species and much longer for two species. Cluster analysis showed that the three species with the longest-lived seeds had smaller (9-11 %) airspaces around the embryo. The post-storage germination method impacted the quality assessment; seeds equilibrated at room temperature for 24 h or in 10 % sucrose solution had improved germination, particularly for the seeds with the smallest embryos. Chromatography revealed that the seeds of all eight species were rich in linoleic acid, and differential scanning calorimetry identified a peak that might be auxiliary to selecting long-lived seeds., Conclusions: These findings show that not all orchids produce seeds that are short lived, and our trait analyses might help to strengthen prediction of seed longevity in diverse orchid species., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Soybean is grown worldwide for its high protein and oil content. Weeds compete fiercely for resources, which affects soybean yields. Because of the progressive enhancement of weed resistance to herbicides and the quickly increasing cost of manual weeding, mechanical weed control is becoming the preferred method of weed control. Mechanical weed control finds it difficult to remove intra-row weeds due to the lack of rapid and precise weed/soybean detection and location technology. Rhodamine B (Rh-B) is a systemic crop compound that can be absorbed by soybeans which fluoresces under a specific excitation light. The purpose of this study is to combine systemic crop compounds and computer vision technology for the identification and localization of soybeans in the field. The fluorescence distribution properties of systemic crop compounds in soybeans and their effects on plant growth were explored. The fluorescence was mainly concentrated in soybean cotyledons treated with Rh-B. After a comparison of soybean seedlings treated with nine groups of rhodamine B solutions at different concentrations ranging from 0 to 1440 ppm, the soybeans treated with 180 ppm Rh-B for 24 h received the recommended dosage, resulting in significant fluorescence that did not affect crop growth. Increasing the Rh-B solutions reduced crop biomass, while prolonged treatment times reduced seed germination. The fluorescence produced lasted for 20 days, ensuring a stable signal in the early stages of growth. Additionally, a precise inter-row soybean plant location system based on a fluorescence imaging system with a 96.7% identification accuracy, determined on 300 datasets, was proposed. This article further confirms the potential of crop signaling technology to assist machines in achieving crop identification and localization in the field.

Environmental factors, such as temperature and moisture, and plant factors, such as seed position on the mother plant, can affect seed viability and germination. However, little is known about the viability and germination of seeds in different positions on the mother plant after burial in soil under natural environmental conditions. Here, diaspores from three positions on a compound spike and seeds from two/three positions in a diaspore of the invasive diaspore-heteromorphic annual grass Aegilops tauschii were buried at four depths for more than 2 years (1-26 months) under natural conditions and viability and germination monitored monthly. Viability of seeds in each diaspore/seed position decreased as burial depth and duration increased and was associated with changes in soil temperature and moisture. Germination was highest at 2 cm and lowest at 10 cm soil depths, with peaks and valleys in autumn/spring and winter/summer, respectively. Overall, seeds in distal diaspore and distal seed positions had higher germination percentages than those in basal diaspore and basal seed positions, but basal ones lived longer than distal ones. Chemical content of fresh diaspores/seeds was related to diaspore/seed position effects on seed germination and viability during burial. We conclude that seeds in distal diaspores/seed positions have a 'high risk' strategy and those in basal positions a 'low risk' strategy. The two risk strategies may act as a bet-hedging strategy that spreads risks of germination failure in the soil seed bank over time, thereby facilitating the survival and invasiveness of A. tauschii., (© 2024 Scandinavian Plant Physiology Society.)

The measurement of germination index (GI) in composting is a time-consuming and laborious process. This study employed four machine learning (ML) models, namely Random Forest (RF), Artificial Neural Network (ANN), Support Vector Regression (SVR), and Decision Tree (DT), to predict GI based on key composting parameters. The prediction results showed that the coefficient of determination (R 2 ) for RF (>0.9) and ANN (>0.9) was higher than SVR (<0.6) and DT (<0.8), suggesting that RF and ANN displayed superior predictive performance for GI. The SHapley additive exPlanations value result indicated that composting time, temperature, and pH were the important features contributing to GI. Composting time was found to have the most significant impact on GI. Overall, RF and ANN were suggested as effective tools for predicting GI in composting. This study offers the reliable approach of accurately predicting GI in composting processes, thereby enabling intelligent composting practices., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

One of the most vulnerable phases in the plant life cycle is sexual reproduction, which depends on effective pollen transfer, but also on the thermotolerance of pollen grains. Pollen thermotolerance is temperature-dependent and may be reduced by increasing temperature associated with global warming. A growing body of research has focused on the effect of increased temperature on pollen thermotolerance in crops to understand the possible impact of temperature extremes on yield. Yet, little is known about the effects of temperature on pollen thermotolerance of wild plant species. To fill this gap, we selected Lotus corniculatus s.l. (Fabaceae), a species common to many European habitats and conducted laboratory experiments to test its pollen thermotolerance in response to artificial increase in temperature. To test for possible local adaptation of pollen thermal tolerance, we compared data from six lowland (389-451 m a.s.l.) and six highland (841-1,030 m a.s.l.) populations. We observed pollen germination in vitro at 15 °C, 25 °C, 30 °C, and 40 °C. While lowland plants maintained a stable germination percentage across a broad temperature range (15-30 °C) and exhibited reduced germination only at extremely high temperatures (40 °C), highland plants experienced reduced germination even at 30 °C-temperatures commonly exceeded in lowlands during warm summers. This suggests that lowland populations of L. corniculatus may be locally adapted to higher temperature for pollen germination. On the other hand, pollen tube length decreased with increasing temperature in a similar way in lowland and highland plants. The overall average pollen germination percentage significantly differed between lowland and highland populations, with highland populations displaying higher germination percentage. On the other hand, the average pollen tube length was slightly smaller in highland populations. In conclusion, we found that pollen thermotolerance of L. corniculatus is reduced at high temperature and that the germination of pollen from plant populations growing at higher elevations is more sensitive to increased temperature, which suggests possible local adaptation of pollen thermotolerance., Competing Interests: The authors declare that they have no competing interests., (© 2024 Jackwerth et al.)

Salinity reduces feijão-caupi production, and the search for tolerant varieties becomes important within the agricultural context, as, in addition to being used in the field, they can be used in genetic improvement. The objective was to for a identify variety that is tolerant to salinity considering the physiological quality of seeds and seedling growth. A 2 × 4 factorial scheme was used, referring to the varieties Pingo-de-ouro and Coruja, and four electrical conductivities of water (0; 3.3; 6.6 and 9.9 dS m-1). The physiological quality of seeds and the growth of seedlings were analyzed, in addition to the cumulative germination. The Pingo-de-ouro variety showed no germination, length of the shoot and root, dry mass of the shoot and root compromised up to electrical conductivity of 6 dS m-1 in relation to 0.0 dS m-1. On the other hand, the Coruja variety showed reduced germination, increased shoot and root length. The creole variety Pingo-de-ouro proved to be tolerant to salinity.

This study investigated the germination capacity (endogenous factor) of Petagnaea gussonei (Spreng.) Rauschert, an endemic monospecific plant considered as a relict species of the ancient Mediterranean Tertiary flora. This investigation focused also on the temporal trends of soil-use, climate and desertification (exogenous factors) across the natural range of P. gussonei. The final germination percentage showed low values between 14 and 32%, the latter obtained with GA 3 and agar at 10 °C. The rising temperatures in the study area will further increase the dormancy of P. gussonei, whose germination capacity was lower and slower at temperatures higher than 10 °C. A further limiting factor of P. gussonei is its dormancy, which seems to be morpho-physiological. Regarding climate trends, in the period 1931-2020, the average temperature increased by 0.5 °C, from 15.4 to 15.9 °C, in line with the projected climate changes throughout the twenty-first century across the Mediterranean region. The average annual rainfall showed a relatively constant value of c. 900 mm, but extreme events grew considerably in the period 1991-2020. Similarly, the land affected by desertification expanded in an alarming way, by increasing from 21.2% in 2000 to 47.3% in 2020. Soil-use changes created also a complex impacting mosaic where c. 40% are agricultural areas. The effective conservation of P. gussonei should be multilateral by relying on germplasm banks, improving landscape connectivity and vegetation cover, and promoting climate policies., (© 2024. The Author(s).)