Soil salinity regulates spatial-temporal heterogeneity of seed germination and seedbank persistence of an annual diaspore-trimorphic halophyte in northern China.

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.

Evolutionary reversal of physical dormancy to nondormancy: evidence from comparative seed morphoanatomy of Argyreia species (Convolvulaceae).

Argyreia is the most recently evolved genus in the Convolvulaceae, and available information suggests that most species in this family produce seeds with physical dormancy (PY). Our aim was to understand the evolution of seed dormancy in this family via an investigation of dormancy, storage behaviour, morphology and anatomy of seeds of five Argyreia species from Sri Lanka. Imbibition, germination and dye tracking of fresh intact and manually scarified seeds were studied. Scanning electron micrographs and hand sections of the hilar area and the seed coat away from the hilar area were compared. Scarified and intact seeds of A. kleiniana, A. hirsuta and A. zeylanica imbibed water and germinated to a high percentage, but only scarified seeds of A. nervosa and A. osyrensis did so. Thus, seeds of the three former species are non-dormant (ND), while those of the latter two have physical dormancy (PY); this result was confirmed by dye-tracking experiments. Since >90% of A. kleiniana, A. hirsuta and A. zeylanica seeds survived desiccation to 10% moisture content (MC) and >90% of A. nervosa and A. osyrensis seeds with a dispersal MC of ~12% were viable, seeds of the five species were desiccation-tolerant. A. nervosa and A. osyrensis have a wide geographical distribution and PY, while A. kleiniana, A. hirsuta and A. zeylanica have a restricted distribution and ND. Although seeds of A. kleiniana are ND, their seed coat anatomy is similar to that of A. osyrensis with PY. These observations suggest that the ND of A. kleiniana, A. hirsuta and A. zeylanica seeds is the result of an evolutionary reversal from PY and that ND may be an adaptation of these species to the environmental conditions of their wet aseasonal habitats.

Environmental and seed-position effects on viability and germination of buried seeds of an invasive diaspore-heteromorphic annual grass.

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.

A long-term experiment reveals no trade-off between seed persistence and seedling emergence.

Information on seed persistence and seedling emergence from the soil seed bank is critical for understanding species coexistence and predicting community dynamics. However, quantifying seed persistence in the soil is challenging; thus, its association with other life-history traits is poorly known on a broad scale. Using germination phenology for 349 species in a 42-yr experiment, we quantified the persistence-emergence correlations and their associations with intrinsic regeneration traits using Bayesian phylogenetic multilevel models. We showed no trade-off between seed persistence and seedling emergence. Physically dormant seeds were more persistent but exhibited lower emergence than nondormant seeds. Monocarpic species had both higher persistence and emergence than polycarpic species. Seed mass posed a marginal proxy for persistence, while emergence almost doubled from the smallest to the largest seeds. This study challenges the traditional assumption and is the first demonstration of noncorrelation between persistence and emergence, probably owing to the complexity of regenerative strategies. Species with short persistence and low emergence would be the most vulnerable for in situ conservation. Our analyses of this unique, long-term dataset provide a strong incentive for further experimental studies and a rich data resource for future syntheses.

Trade-offs between diaspore dispersal and dormancy within a spike of the invasive annual grass Aegilops tauschii.

MAIN CONCLUSION: Differences in dispersal and dormancy of heteromorphic diaspores of Aegilos tauschii may increase its flexibility to invade/occupy weedy unpredictable habitats by spreading risk in space and time. In plant species that produce dimorphic seeds, there often is a negative relationship between dispersal and dormancy, with high dispersal-low dormancy in one morph and low dispersal-high dormancy in the other, which may function as a bet-hedging strategy that spreads the risk of survival and ensures reproductive success. However, the relationship between dispersal and dormancy and its ecological consequences in invasive annual grasses that produce heteromorphic diaspores is not well studied. We compared dispersal and dormancy responses of diaspores from the basal (proximal) to the distal position on compound spikes of Aegilops tauschii, an invasive grass with heteromorphic diaspores. Dispersal ability increased and degree of dormancy decreased as diaspore position on a spike increased from basal to distal. There was a significant positive correlation between length of awns and dispersal ability, and awn removal significantly promoted seed germination. Germination was positively correlated with GA concentration and negatively correlated with ABA concentration, and the ABA: GA ratio was high in seeds with low germination/high dormancy. Thus, there was a continuous inverse-linear relationship between diaspore dispersal ability and degree of dormancy. This negative relationship between diaspore dispersal and degree of dormancy at different positions on a spike of Aegilops tauschii may facilitate seedling survival in space and time.

Burning lignin: overlooked cues for post-fire seed germination.

Information about smoke cues for seed germination is fundamental to understanding fire adaptation. Recently, lignin-derived syringaldehyde (SAL) was identified as a new smoke cue for seed germination, which challenges the assumption that cellulose-derived karrikins are the primary smoke cues. We highlight the overlooked association between lignin and the fire adaptation of plants.

Seed dormancy and germination of the endangered exceptional Hawaiian lobelioid Brighamia rockii.

Premise: The Campanulaceae (Lobelioideae) is the Hawaiian plant family with the most endangered and extinct species. Although seeds of Hawaiian lobelioids are desiccation tolerant, the species are exceptional (i.e., they present challenges at various stages of the conventional ex situ conservation chain) due to their generally poor seed survival at the conventional seed-banking temperature (-18°C). Both morphological dormancy (MD) and morphophysiological dormancy (MPD) have been identified in the seeds of other Hawaiian lobelioids; however, the class of dormancy and germination requirements of the Critically Endangered genus Brighamia have not yet been determined. Methods: We measured the embryonic growth in 12-week-old seeds of B. rockii and tested their germination at three temperature regimes (15/5°C, 20/10°C, and 25/15°C) in light and at 25/15°C in darkness. Results: The embryos grew prior to radicle emergence, and the seeds germinated rapidly to high percentages in all tested conditions. Discussion: Whether fresh B. rockii seeds have MD or MPD still needs to be determined; nevertheless, 12-week-old seeds germinated well in light and darkness, and thus the seeds can be used for conservation purposes. Germination in the dark suggests that the species may not form a long-lived soil seed bank in its native habitat.

Seed germination thermal niche differs among nine populations of an annual plant: A modeling approach.

Germination timing is an important determinant of survival and niche breadth of plants. The annual plant Nigella sativa occurs in diverse environments along a steep temperature gradient and thus is a suitable model for the study of germination behavior in response to temperature. We used a modeling approach to compare the germination thermal niche of seeds of nine populations of N. sativa produced in a common garden. Germination time courses were obtained by a newly developed process-based model, and thermal niche was visualized by plotting germination breadth as a function of after-ripening time. Seeds were sampled five times: immature (2 weeks before maturity), mature, and afterripened for 1, 2, and 5 months. Immature and mature seeds had a greater depth of dormancy than afterripened seeds, as estimated by lower values of high-limit temperatures (T h). Afterripening increased germination percentage, synchrony, and thermal niche breadth of all nine populations. The highest asynchrony was for immature and mature seeds, and afterripening enhanced synchrony. Based on the new graphical method, N. sativa has Type 1 nondeep physiological dormancy, and thus, the germination niche is narrow at seed maturity, leading to a delayed germination strategy that is highly dependent on thermal time accumulated during afterripening. Our findings show that there is considerable variation in the germination thermal niche among populations. Temperature regimes in the natural habitats of N. sativa have played a significant role in shaping variation in thermal niche breadth for seed germination of this annual species. The models used in our study precisely predict germination behavior and thermal niche under different environmental conditions. The germination synchrony model also can estimate germination pattern and degree of dormancy during the year, suggesting a useful method for quantification of germination strategies.

Seed position in spikelet as a contributing factor to the success of the winter annual invasive grass Aegilops tauschii.

Seed position - dependent effects on seed dormancy/germination are well documented at the inflorescence/infructescence level, but less is known about seeds at different positions within a dispersal unit. For the invasive winter annual grass Aegilops tauschii, we quantified morphology, mass and dormancy/germination of seeds from basal (1), middle (2), and distal (3) positions in two spikelet types (Left and Right). We also investigated seedling emergence, survival, plant size and seed production of plants from seeds in different spikelet positions of two spikelet types under different soil nutrient and water conditions. We found that these seed, seedling and plant traits performed as mirror images between the Left and Right spikelet types. The middle seed was significantly the longest and had the maximum mass, while the basal seed was the shortest and had medium mass. Middle seeds had the highest increase in mass during imbibition and the highest germination percentages and rates, while basal seeds had the lowest. Seedling emergence and survival, plant size and seed production for each position of seeds were highest in the added fertilizer combined with regular watering treatment and lowest in the no fertilizer combined with natural moisture, while height of plants derived from the middle and the distal seeds was significantly higher than that of plants derived from the basal seeds under all soil nutrient and water conditions. Seedling survival, number of tillers per plant and seed production per plant from the middle and distal seeds were significantly lower than those from basal seeds under all soil nutrient and water treatments. The considerable variation in seedling emergence and survival, plant size and seed production between seeds in different positions in the spikelet results in much flexibility in all stages of the life cycle, thereby likely contributing to the invasiveness of A. tauschii.

Germination of Seeds from Flowers along a Continuum of Long to Short Styles in the Cold Desert Perennial Herb Ixiolirion songaricum.

We compared seed set, mass, and dormancy/germination of seeds from flowers at three points on the style-length continuum [long (LS), intermediate (IS), and short (SS) styles] in Ixiolirion songaricum. The effects of open and hand pollination (self and cross with pollen from upper and lower-level stamens) on seed set, mass, and dormancy/germination were assessed. Most freshly-matured seeds from LS, IS, and SS flowers were dormant, and dormancy was broken under laboratory and field conditions. After-ripened seeds from LS and IS flowers germinated to significantly higher percentages than those from SS flowers. In all pollination treatments, seed set and mass were significantly higher for LS and IS than for SS flowers. Seed set, mass, and germination for LS, IS, and SS flowers were significantly higher in open-pollinated and in cross-pollinated with pollen from upper and lower-level stamens than in self-pollination with pollen from upper- and lower-level stamens. These differences in offspring reproductive traits may be adaptive for I. songaricum in its rainfall-unpredictable environment. This is the first study to demonstrate the association between style length and germination in a species with continuous variation in style length.

Seed dormancy in space and time: global distribution, paleoclimatic and present climatic drivers, and evolutionary adaptations.

Seed dormancy is an important life history state that increases survival and fitness of seed plants, and thus it has attracted much attention. However, global biogeography, effects of paleoenvironment, evolutionary roles of dormancy transitions, and differences in adaptations of seed dormancy between life-forms are poorly understood. We compiled global distribution records for seed dormancy of 12 743 species and their phylogeny to explore the biogeographic patterns, environmental drivers, and evolutionary transitions between seed dormancy and nondormancy. Biogeographic patterns reveal a low proportion of dormancy in tropical rainforest regions and arctic regions and a high proportion of dormancy in remaining tropical, subtropical, and temperate regions for all species and woody species. Herbaceous plants show a greater proportion of dormancy in most global regions except arctic regions. Seasonal environments have a consistent positive influence on the dormancy pattern for both life-forms, but precipitation and temperature were important driving factors for woody and herbaceous plants, respectively. Seed dormancy was the dominating state during the evolutionary history of seed plants, and dormancy transitions had a significant relationship with paleotemperatures. Dormancy and nondormancy transitions in response to fluctuating environments during long-term evolutionary history may have played important roles in the diversification of seed plants. Our results add to the current knowledge about seed dormancy from macro-adaptive perspectives and the potential adaptive mechanisms of seed plants.

Plant canopy may promote seed dispersal by wind.

Seed dispersal has received much research attention. The plant canopy can intercept diaspores, but the effect of the plant canopy (the aboveground portion of a plant consisting of branches and leaves) on dispersal distance has not been explored empirically. To determine the effect of plant canopy on seed dispersal distance, a comparison of diaspores falling through open air and through plant canopy was made in a wind tunnel using three wind speeds and diaspores with various traits. Compared with diaspores falling through open air, the dispersal distance of diaspores falling through plant canopy was decreased or increased, depending on wind speed and diaspore traits. When falling through a plant canopy, dispersal distance of diaspores with thorns or those without appendages was promoted at low wind speed (2 m s-1), while that of diaspores with low wing loading (0.5 mg mm-2) and terminal velocity (2.5 m s-1) was promoted by relatively high (6 m s-1) wind speed. A plant canopy could increase seed dispersal distance, which may be due to the complicated updraft generated by canopy. The effect of maternal plants on seed dispersal regulates the distribution pattern and the species composition of the community.

Seed development in Paeonia ostii (Paeoniaceae), with particular reference to embryogeny.

BACKGROUND: Seeds of Paeonia ostii have been proposed as a source of raw material for the production of edible oil; however, lack of information about the developmental biology of the seeds hampers our ability to use them. Our aim was to investigate development of the seed coat, endosperm and embryo of P. ostii in relation to timing of accumulation of nutrient reserves from pollination to seed maturity. Ovules and developing seeds of P. ostii were collected at various stages of development from zygote to maturity. Seed fresh mass, dry mass, germination, moisture, soluble sugars, starch, protein and oil content were determined. Ontogeny of seeds including embryo, endosperm and seed coat were analyzed histologically. RESULTS: The ovule of P. ostii is anatropous, crassinucellate and bitegmic. The zygote begins to divide at about 5 days after pollination (DAP), and the division is not accompanied by cell wall formation. By 25 DAP, the proembryo begins to cellularize. Thereafter, several embryo primordia appear at the surface of the cellularized proembryo, but only one matures. Endosperm development follows the typical nuclear type. The seed coat is derived from the outer integument. During seed development, soluble sugars, starch and crude fat content increased and then decreased, with maximum contents at 60, 80 and 100 DAP, respectively. Protein content was relatively low compared with soluble sugars and crude fat, but it increased throughout seed development. CONCLUSIONS: During seed development in P. ostii, the seed coat acts as a temporary storage tissue. Embryo development of P. ostii can be divided into two stages: a coenocytic proembryo from zygote (n + n) that degenerates and a somatic embryo from peripheral cells of the proembryo (2n → 2n). This pattern of embryogeny differs from that of all other angiosperms, but it is similar to that of gymnosperms.

Global patterns of potential future plant diversity hidden in soil seed banks.

Soil seed banks represent a critical but hidden stock for potential future plant diversity on Earth. Here we compiled and analyzed a global dataset consisting of 15,698 records of species diversity and density for soil seed banks in natural plant communities worldwide to quantify their environmental determinants and global patterns. Random forest models showed that absolute latitude was an important predictor for diversity of soil seed banks. Further, climate and soil were the major determinants of seed bank diversity, while net primary productivity and soil characteristics were the main predictors of seed bank density. Moreover, global mapping revealed clear spatial patterns for soil seed banks worldwide; for instance, low densities may render currently species-rich low latitude biomes (such as tropical rain-forests) less resilient to major disturbances. Our assessment provides quantitative evidence of how environmental conditions shape the distribution of soil seed banks, which enables a more accurate prediction of the resilience and vulnerabilities of plant communities and biomes under global changes.

Is the Life History Flexibility of Cold Desert Annuals Broad Enough to Cope with Predicted Climate Change? The Case of Erodium oxyrhinchum in Central Asia.

Interannual seasonal variability in precipitation may strongly affect the life history and growth of desert annual plants. We compared the effects of dry and wet springs and dry and wet autumns on growth and F2 seed dormancy of plants from spring (SG)- and autumn (AG)-germinated seeds of the cold desert annual Erodium oxyrhinchum. Vegetative and reproductive growth and F2 seed dormancy and germination were monitored from September 2016 to November 2020 in the sandy Gurbantunggut Desert in NW China in Central Asia. Dry autumns decreased the density of AG plants, and dry springs decreased the density of SG plants and growth of SG and AG plants. In dry springs, SG plants were more sensitive to precipitation than AG plants, while in wet springs SG and AG plants had similar responses to precipitation. During growth in both dry and wet springs, most morphological characters of SG and AG plants initially increased rapidly in size/number and then plateaued or decreased, except for SG plants in dry springs. In dry springs, most morphological characters of AG plants were larger or more numerous than those of SG plants, and they were larger/more numerous for SG plants in wet than in dry springs. The percentage biomass allocated to reproduction in SG plants was slightly higher in a wet than in a dry spring. A much higher proportion of dormant seeds was produced by AG plants in a wet spring than in a dry spring. Projected changes in precipitation due to climate change in NW China are not likely to have much of an effect on the biology of this common desert annual plant.

Effect of Nitrogen Addition on Selection of Germination Trait in an Alpine Meadow on the Tibet Plateau.

Seed germination requirements may determine the kinds of habitat in which plants can survive. We tested the hypothesis that nitrogen (N) addition can change seed germination trait-environmental filter interactions and ultimately redistribute seed germination traits in alpine meadows. We determined the role of N addition on germination trait selection in an alpine meadow after N addition by combining a 3-year N addition experiment in an alpine meadow and laboratory germination experiments. At the species level, germination percentage, germination rate (speed) and breadth of temperature niche for germination (BTN) were positively related to survival of a species in the fertilized community. In addition, community-weighted means of germination percentage, germination rate, germination response to alternating temperature and BTN increased. However, germination response to wet-cold storage (cold stratification) and functional richness of germination traits was lower in alpine meadows with high-nitrogen addition than in those with no, low and medium N addition. Thus, N addition had a significant influence on environmental filter-germination trait interactions and generated a different set of germination traits in the alpine meadow. Further, the effect of N addition on germination trait selection by environmental filters was amount-dependent. Low and medium levels of N addition had less effect on redistribution of germination traits than the high level.

A Seed Mucilage-Degrading Fungus From the Rhizosphere Strengthens the Plant-Soil-Microbe Continuum and Potentially Regulates Root Nutrients of a Cold Desert Shrub.

Seed mucilage plays important roles in the adaptation of desert plants to the stressful environment. Artemisia sphaerocephala is an important pioneer plant in the Central Asian cold desert, and it produces a large quantity of seed mucilage. Seed mucilage of A. sphaerocephala can be degraded by soil microbes, but it is unknown which microorganisms can degrade mucilage or how the mucilage-degrading microorganisms affect rhizosphere microbial communities or root nutrients. Here, mucilage-degrading microorganisms were isolated from the rhizosphere of A. sphaerocephala, were screened by incubation with mucilage stained with Congo red, and were identified by sequencing and phylogenetic analyses. Fungal-bacterial networks based on high-throughput sequencing of rhizosphere microbes were constructed to explore the seasonal dynamic of interactions between a mucilage-degrading microorganism and its closely related microorganisms. The structural equation model was used to analyze effects of the mucilage-degrading microorganism, rhizosphere fungal-bacterial communities, and soil physicochemical properties on root C and N. The fungus Phanerochaete chrysosporium was identified as a mucilage-degrading microorganism. Relative abundance of the mucilage-degrading fungus (MDF) was highest in May. Subnetworks showed that the abundance of fungi and bacteria closely related to the MDF also were highest in May. Interactions between the MDF and related fungi and bacteria were positive, which might enhance mucilage degradation. In addition, the MDF might regulate root C and N by affecting rhizosphere microbial community structure. Our results suggest that MDF from the rhizosphere strengthens the plant-soil-microbe continuum, thereby potentially regulating microbial interactions and root nutrients of A. sphaerocephala.[Formula: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

The pleurogram, an under-investigated functional trait in seeds.

BACKGROUND: A structure called the pleurogram makes up a large part of the seed coat of some species in subfamilies Caesalpinioideae and Mimosoideae of Fabaceae, but little is known about its function. It has been hypothesized that this structure acts as a hygroscopic valve during the maturation drying of seeds. However, a new hypothesis has recently emerged that proposes a distinct function for the pleurogram. SCOPE: Here, we provide an overview of the structure and function of the pleurogram, which is diverse and complex. This large structure can be dislodged, thereby creating a pathway for water entry into water-impermeable seeds. However, the pleurogram is non-functional as a pathway of water into the seed of some species. Thus, the evolutionary history of species with a pleurogram may be related to a loss/gain in its function. A complete model for the function of the pleurogram is proposed. CONCLUSIONS: The pleurogram may act on several stages of the seed, from maturation to germination. As a hygroscopic valve, it regulates dehydration of the seed during maturation. As a pathway for water entry into the seed, the pleurogram acts as a water gap in seeds with physical dormancy, thereby regulating dormancy break/germination. The occurrence of a pleurogram in several genera of legumes and Cucurbitaceae is confirmed. Single or multiple pleurograms can serve as (the) point(s) of water entry into seeds that do not otherwise have a hilar water gap.

Dormancy and germination of the trimorphic achenes of a cold desert annual: spreading the risk over time.

Many studies have been done on the relationship between variation in morphology, dispersal ability and degree of dormancy of heterocarpic species with dimorphic diaspores. However, there are far fewer such studies on species that produce trimorphic diaspores. Our aim was to compare dormancy and germination of achenes from peripheral, intermediate and central positions in the capitulum of the diaspore-trimorphic cold desert annual Asteraceae species Heteracia szovitsii, an important component of plant communities in the cold deserts of NW China. Dormancy breaking/germination responses of the three achene morphs and of seeds isolated from the pericarp were tested in the laboratory using standard procedures, and seedling emergence phenology of the achene morphs was monitored under natural cold desert temperature conditions in an experimental garden with and without supplemental watering. Depth of dormancy of the three achene morphs was peripheral > intermediate > central. Seedlings from the three morphs emerged in spring and in autumn. Cumulative seedling emergence percentage from achenes during 47 months of burial was central > intermediate > peripheral. Central achene morphs emerged over a period of ~12 months after sowing, while intermediate and peripheral achene morphs did so for ~40 and 47 months, respectively. Thus, H. szovitsii exhibits a temporal dispersal strategy. No viable central or intermediate achene morphs were present after 16 and 40 months, respectively, but ~60 % of the non-emerged peripheral achenes morphs were viable after 47 months. Based on our results on diaspore dormancy and those of a previous study of diaspore spatial dispersal of H. szovitsii, we conclude that this species has a high-intermediate-low risk diaspore dispersal/dormancy strategy that likely increases the chances for population persistence over time and space.