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Incorporating native shrubs into restoration projects can improve biodiversity conservation and enhance the sustainability of ecosystem functions. Shrubs grow under different forest canopy structures, having varied microclimatic conditions according to forest type and composition. Currently, there is a lack of information on propagation from seed and planting material availability for the utilization of shrubs in forest restoration.In the present study, we evaluated the effects of temperature and light on germination of ten shrub species (Ardisia japonica, Callicarpa cathayana, Callicarpa giraldii var. subcanescens, Deutzia schneideriana, Fraxinus sieboldiana, Hydrangea chinensis, Maesa japonica, Rhododendron simsii, Spiraea japonica var. fortunei and Weigela japonica var. sinica) occurring in subtropical forests in China.No seeds of any species germinated in the coolest thermal regime (5/10 °C), while optimal temperature requirements varied from 10/20 °C to 25/35 °C. Seeds of small‐seeded species had higher germination percentages in the light treatments, while larger seeds were not photoblastic. There was no relationship between germination in the light and the seed shape index.Our results may assist in identification of seed traits and suitable shrub species for restoration in specific forest types, thus aiding native forest recovery of structure and composition. Successful recovery leads to enhanced biodiversity, reestablishment of microhabitats and ecological interactions in the forest understorey. [ABSTRACT FROM AUTHOR]

In degraded karst ecosystem, vegetation restoration efforts almost exclusively rely on planted seedlings, but this is not effective to maintain community diversity and resilience. As seed functional traits, seed dormancy and germination are key to community assembly. Unfortunately, these elements are commonly overlooked in restoring degraded ecosystems.This work classifies seed dormancy of 27 species with different life forms that are common on a degraded karst mountain. We examined the effects of temperature regime and light conditions on percentage germination and assessed the relationships between seed traits and germination index using a partial least squares regression (PLSR).Approximately 48% of the investigated species had physiological dormancy, 37% were non‐dormant, 7% had morphophysiological dormancy, 4% had morphological dormancy and 4% had physical dormancy. We found that 94% (15 out of 16) species had maximum germination in warm temperature regimes (20/13 and 25/18 °C), while the remaining species required cool temperatures (10/4 °C). PLSR analysis indicated a significant positive correlation between seed mass and T50m (time to 50% final germination), and a negative correlation between seed moisture content and percentage germination.Our findings indicate that seed traits are important factors in seed‐based restoration practice. F. esculentum, O. opipara, P. fortuneana and S. salicifolia are recommended for direct seeding during the early rainy season to restore seriously degraded lands in subtropical karst regions. [ABSTRACT FROM AUTHOR]

Loss of sexual reproductive capacity has been proposed as a syndrome of domestication in vegetatively propagated crops, but there are relatively few examples from agricultural systems. In this study, we compare sexual reproductive capacity in wild (sexual) and domesticated (vegetative) populations of enset (Ensete ventricosum (Welw.) Cheesman), a tropical banana relative and Ethiopian food security crop.We examined floral and seed morphology and germination ecology across 35 wild and domesticated enset. We surveyed variation in floral and seed traits, including seed weight, viability and internal morphology, and germinated seeds across a range of constant and alternating temperature regimes to characterize optimum germination requirements.We report highly consistent floral allometry, seed viability, internal morphology and days to germination in wild and domesticated enset. However, seeds from domesticated plants responded to cooler temperatures with greater diurnal range. Shifts in germination behaviour appear concordant with a climatic envelope shift in the domesticated distribution.Our findings provide evidence that sexual reproductive capacity has been maintained despite long‐term near‐exclusive vegetative propagation in domesticated enset. Furthermore, certain traits such as germination behaviour and floral morphology may be under continued selection, presumably through rare sexually reproductive events. Compared to sexually propagated crops banked as seeds, vegetative crop diversity is typically conserved in living collections that are more costly and insecure. Improved understanding of sexual propagation in vegetative crops may have applications in germplasm conservation and plant breeding. [ABSTRACT FROM AUTHOR]

Meaningful conservation techniques for the endangered Morus boninensis require seed production and storage, since in situ purebred seed production is infrequent in Ogasawara Islands (World Natural Heritage Site) in Japan.Ex situ living M. boninensis specimens produced seeds by open‐ and artificial‐pollination in a greenhouse. Seed desiccation tolerance and storage characteristics were examined. Open‐pollinated seeds were dried at 75, 33 and 8% relative humidity (RH) for 5 days then cryopreserved at −170 °C. Artificially pollinated seeds were dried at 8% RH then stored cryogenically at −170 °C and in freezers at −80 or −20 °C for 6 months. Germination rates were compared among seeds before and after drying and storage.Germination rates of undried seeds were 83% for open‐pollinated seeds and 65% for artificially pollinated seeds. M. boninensis seeds exhibited the characteristic high desiccation tolerance of orthodox seeds and maintained a high germination rate after drying to a moisture content of approximately 4%. Cryopreservation of open‐pollinated dry seeds with moisture contents of ca. 12, 7 and 4% maintained germination rates, while cryopreservation of undried seeds (moisture content ca. 44%) resulted in no germinability. Cryogenic and freezer storage of artificially pollinated dry seeds for 6 months resulted in maintenance of germination rates comparable to undried seeds before storage.Seed production was enabled by ex situ M. boninensis collection. The present study also developed a method for low temperature seed storage. Ex situ living tree collection represents a feasible seed resource for reintroduction and restoration programmes for M. boninensis. [ABSTRACT FROM AUTHOR]

Available studies are far from giving a complete figure for the germination requirements of many Mediterranean Basin species.In this study, we investigated the germination properties of Lavandulastoechas L. (Lamiaceae) in response to different light and temperature regimes. We performed comprehensive experiments to test the effect of fixed and alternating temperatures, dark versus light conditions, and thermodormancy or thermoinhibition on several germination properties in three populations of L. stoechas from southwestern Turkey.Germination patterns showed a substantial variation among populations. Germination percentage was higher in the light conditions than in the dark at most temperatures, and alternating temperatures substituted light for the germination. The requirement of L. stoechas seeds to light for germination gradually increased through lower and higher temperatures than 15 °C. High temperature (30 °C) reduced the germination percentage to zero. However, in the presence of light, seeds were able to germinate after transferring to the optimum temperature (thermoinhibition), but this was not the case in darkness (thermodormancy). Seed germination in L. stoechas was stimulated by light, suggesting that germination has a phytochrome‐mediated response.Our study makes an inference to the fire‐environment interactions in the germination of Mediterranean seeder species by showing that both light and alternating temperatures stimulate germination in L. stoechas, a species well‐known with its fire‐related germination. Comprehensive germination studies are required for a better understanding of the early life‐stage adaptations of plants to Mediterranean conditions, and for developing more robust strategies for conservation and ecosystem restoration. [ABSTRACT FROM AUTHOR]

We investigated how developmental stage affects seed traits, including the relative level of desiccation tolerance of Quercus serrata. We tested the hypothesis that the relative level of desiccation tolerance is a quantitative trait associated with seed development and that a maximum relative level of desiccation tolerance is reached during development.Seed growth and physiological traits of Q. serrata from a subtropical forest were examined in detail during the developmental process.During seed development, the relative level of desiccation tolerance and other seed traits of Q. serrata varied. Dry matter accumulation in seed components increased rapidly beginning in mid‐August, and moisture content declined. At the peak period of seed dispersal in late September, seeds were fully mature, with 100% germination. Relative level of desiccation tolerance increased up to the point of peak dispersal; however, at this time seeds were still recalcitrant. Post‐mature development was accompanied by further increases in seed dry matter and decreases in moisture content, which led to a decrease in seed germination and relative level of desiccation tolerance.Our results suggest that in species with recalcitrant seeds, the relative level of desiccation tolerance and other seed traits are quantitative at the intraspecific level. The relative level of desiccation tolerance for recalcitrant seeds does not increase infinitely during phase II of development. There is a maximum relative level of desiccation tolerance in recalcitrant seeds within a species. [ABSTRACT FROM AUTHOR]

To mitigate anthropogenic impacts on plant diversity in tropical montane grasslands, one of the most threatened ecosystems in Brazil, it will be essential to develop ex situ conservation strategies to preserve wild species. The lack of basic research on the seed storage behaviour of grassland species may, however, limit their use for reintroduction and restoration projects.We investigated seed storage behaviour at the community level by comparing the effects of cold–low RH (10 °C; 10% RH) and freezing–low RH (20 °C; 10% RH) conditions on seed viability, germination and dormancy of 47 species.Fresh seeds of 43% of the species showed primary dormancy. More than half of the species showed high seed survival responses (viability >60%) under both storage temperatures. Despite a variety of dormancy responses among the different species, the low RH storage conditions tested released dormancy for most species during 12‐ and 30‐month storage times. Multivariate analysis of the best (freezing–low RH, 30 months) storage condition evidenced the formation of five distinct groups, three with species having high conservation potential in seed banks.Although further studies are needed to test dormancy‐breaking treatments and improve seed conservation practices, this first approach to assessing seed banking techniques could contribute to demand for locally adapted seeds for ecological restoration projects in tropical montane grasslands. [ABSTRACT FROM AUTHOR]

Hydrothermal time (HTT) and halothermal time (HaloTT) models were used to quantitatively characterize the combined effects of temperature (T), water potential (ψ) and NaCl concentration on seed germination of canola after different accelerated ageing periods (AAP) at 42 °C and 100% humidity.Seed germination time courses were observed and electrical conductivities of seed leachates were measured in all experiments.The cardinal temperatures estimated by both models were 4.6, 28 and 35 °C for the base (Tb), optimum (To) and ceiling (Tc) temperatures in water (0 MPa), respectively, when the seeds were not aged. The Tb increased with AAP, while the Tc decreased and the To remained constant at all AAP. Below To, the median base water potentials (ψb(50)) were −1.07, −0.73, −0.48 and −0.39 MPa for the AAP levels of 0, 24, 36 and 48 h, respectively. These values were more negative when germination occurred in salt solutions (the base NaCl concentrations converted to ψ were −1.25, −0.81, −0.51 and −0.41 MPa, respectively), due to uptake of salt ions. Thresholds became more positive above To and reached zero at Tc in all AAP.Seed osmotic adjustment capacity declined linearly with increasing AAP while the conductivity of seed leachates increased in association with the loss of seed vigour. Significant correlations between conductivity results and the parameters of HTT and HaloTT models suggest that they could be considered as effective descriptors of canola seed vigour. [ABSTRACT FROM AUTHOR]

Long‐term forest dynamics monitoring plots provide information on number of individual species in the plot, allowing us for the first time to construct seed dormancy profiles at the species and individual levels for a specific site.Focusing on the Xishuangbanna tropical season rainforest plot (XTRDP), we used data from nine forest dynamics plots (two for tropical, four for subtropical and three for temperate) and information on kind of seed dormancy to generate seed dormancy profiles for communities across tropical to temperate latitudes at the species and individual levels. Seed dormancy information was collected from previous publications, and some data were provided by two germplasm banks that test seed germination of wild plants in China.In XTRDP, 35% of the species and 58% of individuals have non‐dormant seeds; the dominant species have non‐dormant seeds. In all plots, the most common kind of dormancy among species and individuals with dormant seeds was physiological dormancy. At the species level, the profile for tropical, subtropical and temperate plots was similar to profiles for each of these vegetation regions. In all plots, except one subtropical plot, the percentage of species versus individuals with dormant seeds differed. All temperate plots had a higher percentage of individuals than species with dormant seeds, but this pattern was not consistent for tropical or subtropical plots.We show that dormancy increases with latitude at both the species and individual levels. Dormancy profiles at the individual tree level provide new insight into seed dormancy relationships within plant communities. [ABSTRACT FROM AUTHOR]

Disjunct species in the same genus are a common feature of the flora in the temperate forests of East Asia and eastern North America. This study aimed to evaluate whether the kind of seed dormancy was maintained after species in the genus Asarum (Aristolochiaceae) were separated from their common ancestor.We classified the seed dormancy of Asarum sieboldii, an East Asian species, based on a phenology study and experiments in controlled temperature conditions, and then compared it to that of the previously studied A. canadense, an eastern North American species.The underdeveloped embryo of A. sieboldii grew and germinated (radicle emergence) in autumn but shoot emergence did not occur until the following spring. The seeds of A. sieboldii had deep simple epicotyl morphophysiological dormancy because the seeds with emerged radicle required a relatively long period of cold stratification to break epicotyl dormancy and produce a shoot.Although the seed of A. sieboldii had weaker radicle dormancy and stronger epicotyl dormancy compared to A. canadense, the kind of seed dormancy was the same for the two species. The trait of seed dormancy was inherited from a shared common ancestor and maintained in populations well after the two species (or their ancestors) separated. However, quantitative differences in temperature requirements for radicle and shoot emergence suggest the possibility of adaptation to the environment. [ABSTRACT FROM AUTHOR]

Community‐level seed dormancy studies are important in understanding the dynamics of plant communities and adaptations of species to their habitat. Our aim was to develop a seed dormancy profile for tropical montane forests of Sri Lanka, which are a global biodiversity hotspot, and compare it to the profile made using a world database for this vegetation type.Germination, imbibition and embryo length : seed length ratio of seeds were determined for 80 Sri Lankan montane forest species.Seeds of 31 species were fast‐germinating with a median length of germination (MLG) <30 days and the remaining 49 were slow‐germinating with MLG >30 days. Embryos of six fast‐germinating species grew prior to radicle emergence, indicating morphological dormancy (MD). The other 25 fast‐germinating species had non‐dormant (ND) seeds. Manually scarified seeds of two species imbibed significantly more water than non‐scarified seeds, revealing physical dormancy (PY). Embryos of 20 slow‐germinating species grew prior to radicle emergence, confirming morpho‐physiological dormancy (MPD). The remaining slow‐germinating species had a fully developed embryo and thus physiological dormancy (PD). The percentage of species with ND seeds and with MD, MDP, PD and PY was 31, 7.5, 25, 34 and 2.5, respectively.Species with dormant seeds (70%) dominate the Sri Lankan montane forest community similar to the world database, with 85% dormant seeds. Seed dormancy may be an adaptation that prevents seeds from germinating during the Sri Lankan dry season from December to March when conditions are unfavourable for seedling growth due to low water availability. [ABSTRACT FROM AUTHOR]

Dormancy cycling is a key mechanism that contributes to the maintenance of long‐term persistent soil seed banks, but has not been recorded in long‐lived woody shrub species from fire‐prone environments. Such species rely on seed banks and dormancy break as important processes for post‐fire recruitment and recovery.We used germination experiments with smoke treatments on fresh seeds and those buried for 1 year (retrieved in spring) and 1.5 years (retrieved the following late autumn) to investigate whether Asterolasia buxifolia, a shrub from fire‐prone south‐eastern Australia with physiologically dormant seeds, exhibited dormancy cycling.All seeds had an obligation for winter seasonal temperatures and smoke to promote germination, even after ageing in the soil. A high proportion of germination was recorded from fresh seeds. but germination after the first retrieval was significantly lower, despite high seed viability. After the second retrieval, germination returned to the initial level. This indicates a pattern of annual dormancy cycling; one of the few observations, to our knowledge, for a perennial species. Additionally, A. buxifolia's winter temperature and smoke requirements did not change over time, highlighting the potential for seeds to remain conditionally dormant (i.e. restricted to a narrow range of germination conditions) for long periods.For physiologically dormant species, such as A. buxifolia, we conclude that dormancy cycling is an important driver of successful regeneration, allowing seed bank persistence, sometimes for decades, during fire‐free periods unsuitable for successful recruitment, while ensuring that a large proportion of seeds are available for recruitment when a fire occurs. [ABSTRACT FROM AUTHOR]

To understand how adaptive evolution in life-cycle phenology operates in plants, we need to unravel the effects of geographic variation in putative agents of natural selection on life-cycle phenology by considering all key developmental transitions and their co-variation patterns. We address this goal by quantifying the temperature-driven and geographically varying relationship between seed dormancy and flowering time in the annual Arabidopsis thaliana across the Iberian Peninsula., We used data on genetic variation in two major life-cycle traits, seed dormancy ( DSDS50) and flowering time ( FT), in a collection of 300 A. thaliana accessions from the Iberian Peninsula. The geographically varying relationship between life-cycle traits and minimum temperature, a major driver of variation in DSDS50 and FT, was explored with geographically weighted regressions ( GWR). The environmentally varying correlation between DSDS50 and FT was analysed by means of sliding window analysis across a minimum temperature gradient., Maximum local adjustments between minimum temperature and life-cycle traits were obtained in the southwest Iberian Peninsula, an area with the highest minimum temperatures. In contrast, in off-southwest locations, the effects of minimum temperature on DSDS50 were rather constant across the region, whereas those of minimum temperature on FT were more variable, with peaks of strong local adjustments of GWR models in central and northwest Spain. Sliding window analysis identified a minimum temperature turning point in the relationship between DSDS50 and FT around a minimum temperature of 7.2 °C. Above this minimum temperature turning point, the variation in the FT/ DSDS50 ratio became rapidly constrained and the negative correlation between FT and DSDS50 did not increase any further with increasing minimum temperatures., The southwest Iberian Peninsula emerges as an area where variation in life-cycle phenology appears to be restricted by the duration and severity of the hot summer drought. The temperature-driven varying relationship between DSDS50 and FT detected environmental boundaries for the co-evolution between FT and DSDS50 in A. thaliana. In the context of global warming, we conclude that A. thaliana phenology from the southwest Iberian Peninsula, determined by early flowering and deep seed dormancy, might become the most common life-cycle phenotype for this annual plant in the region. [ABSTRACT FROM AUTHOR]