AoB Plants最新文献

Habitat variability critically influences plant reproductive strategies and pollinator attributes. However, studies on intraspecific variation in vegetative and floral traits, pollinator attributes, and seed traits remain limited in the context of small-scale habitat heterogeneity, particularly meadows interspersed with sandy patches. On the Tibetan Plateau, discrete sandy patches (some as small as 10 m²) occur within alpine meadows. We hypothesized that distinct plant reproductive strategies and pollinator attributes exist between meadows and sandy habitats at a microhabitat scale. To test this hypothesis, we conducted a field experiment to investigate variation in floral traits, pollinator attributes, and seed traits in a Tibetan alpine herb (Astragalus purpurinus) across meadow and sandy habitats. Our results show that meadow populations produced fewer nectar-enriched flowers with high sugar concentrations, fewer and larger seeds, and were pollinated primarily by bumble bees. In contrast, sandy-habitat populations produced numerous nectar-poor flowers with low sugar concentrations, more numerous small seeds, and relied on mason bees for pollination. Our results demonstrate that micro-scale habitat heterogeneity drives divergent plant reproductive strategies and pollinator attributes within a single species. These findings reveal novel mechanisms by which small-scale environmental variation shapes reproductive adaptation in alpine ecosystems.

Leaf traits are crucial to seedling growth and survival, and their plasticity can influence seedling fitness in changing environments. Seedlings of Artemisia tridentata, a keystone shrub of the western North American sagebrush steppe, show heteromorphic leaf development. Early leaves are larger and less pubescent than those produced later, suggesting a shift from characteristics favouring rapid growth to those increasing drought tolerance. To investigate this hypothesis, we determined the specific leaf area (SLA) and the osmotic potential at full turgor (π₀) of early and late leaves, and measured their stomatal conductance and photosynthetic rates as leaf water potential (Ψ_l) declined under imposed drought. We also examined whether water stress could trigger late leaf development. At high Ψ_l and per area, early and late leaves had similar photosynthetic rates. However, the SLA of early leaves was three times higher than that of late leaves, yielding higher photosynthetic rates per unit mass in the former. Late leaves had lower π₀ and were less sensitive to drought, exhibiting a lower Ψ_l at 50% of maximum photosynthesis than early leaves. Drought triggered the shedding of early leaves and the initiation of late-like leaves. Formation of these leaves continued upon return to well-watered conditions, possibly indicating stress memory. The overall results suggest that early leaves enhance growth during wet springs following germination, while late leaves prolong photosynthesis as water potentials decline during summer drought. The adaptive value of early leaves may be diminishing due to changing environmental conditions that are accelerating the onset of drought.

Understanding how leaf morphology mediates plant responses to environmental variability is critical for predicting species adaptability under climate change. This study examines whether intraspecific variation in leaf shape among Chenopodium hircinum populations is linked to physiological and functional trait differences and whether such variation reflects adaptive responses to source climate. We cultivated 11 populations of C. hircinum from diverse climatic origins in a common garden experiment. Leaf shape was quantified using descriptors (aspect ratio, circularity, solidity), landmarks, and Elliptical Fourier Descriptors. Physiological traits (stomatal conductance, leaf temperature, chlorophyll content) and functional traits (leaf area, leaf dry weight and leaf mass per area) were measured and analysed in relation to shape and environmental data. Leaf morphology varied significantly among populations and was associated with climatic conditions at origin, especially mean summer temperature. Functional and physiological traits were not directly correlated with environmental variables but showed strong associations with leaf shape. Landmark-based PC2 (lobed vs. rounded forms) and aspect ratio emerged as key predictors of trait variation. Most trait variation occurred at the individual level rather than among populations. Our findings highlight leaf shape as a central mediator linking environmental heterogeneity to physiological function. This suggests that morphology-driven trait integration may enhance adaptability in C. hircinum. Intraspecific diversity in shape and associated traits could serve as a reservoir of resilience under climate change, reinforcing the evolutionary and applied significance of wild relatives in crop improvement.

Climate warming threatens plant sexual reproduction, and plants with extended flowering can experience distinct biotic and abiotic environments across the season. Therefore, responses and adaptations of plant reproduction to warming may vary across the season. Our aim was to examine how climate warming affects plant floral traits and reproductive success across different phenological stages within a single flowering season. In this study, infrared heaters were used to simulate warming (+1.5°C) during the growing season of Impatiens oxyanthera. Flowering was divided into early, middle, and late time-periods based on the flowering onset and end dates of the experimental population. The changes in floral and reproductive characteristics, as well as their relationships across these three time periods, were investigated under warming conditions. Our study on I. oxyanthera demonstrates that warming significantly delayed flowering onset, reduced the number of flowers per plant, and decreased both the length and curvature of nectar spurs. Warming also disrupted correlations between floral traits to some extent compared with the control. Flowers that opened during the late period were smaller, had fewer ovules but more nectar, and produced fewer filled seeds. Warming exerted period-specific impacts on nectar spur length, reducing it during the late flowering period compared with the control treatment but not during the early or middle periods. However, the changes in floral traits caused by the interaction of warming and flowering period did not significantly affect reproductive success at the single-fruit level. These findings highlight the temporal heterogeneity of plant responses to climate warming and suggest that potential buffering mechanisms might contribute to maintaining reproductive outcomes under moderate warming conditions.

Soil nutrient heterogeneity has generally been shown to benefit alien plants more than native ones. However, whether drought, an important aspect of climate change, alters these effects remains an open question. We used a greenhouse experiment with two alien and two native herbaceous plants. Plants were grown either alone or in a mixture (one alien plant and one native plant) in homogeneous and heterogeneous soils, with or without drought. We found that shoot mass of the native plant Alternanthera sessilis and the alien plant Celosia argentea were 27.4% and 76.6% lower in heterogeneous soils than homogenous soils, respectively, indicating a negative effect of soil nutrient heterogeneity. However, these negative effects were eliminated when the plants were grown alone in drought conditions. In contrast, soil nutrient heterogeneity, drought, and competition had little effect on the growth of the native plant Achyranthes bidentata and the alien plant Amaranthus retroflexus. These results suggest that plant species differ in their growth responses to complex environmental changes. These results may have implications for understanding plant invasion outcomes in heterogeneous environments under global climate changes.

Wheat is the most cultivated crop worldwide, and Australia consistently ranks among the top wheat-exporting countries. Although modern technology has expanded the speed and accuracy of conventional breeding, progress is constrained by limited genetic diversity and linkage drag, with new wheat varieties often taking 8-12 years to reach the market. Biotech methods involving the transformation of foreign DNA into genomes [genetic modification (GM)], or editing of native DNA [genome editing (GEd)], provide novel opportunities to efficiently improve traits alongside conventional breeding. In 2020, the world's first GM drought-tolerant bread wheat (HB4) hit the market in Argentina. The USA recently approved HB4 wheat for commercial cultivation, and human consumption of HB4 wheat has been approved by nine countries, including Australia. Currently, 25 countries, Australia included, have deregulated GEd crops in some form, and many other countries have indicated that they will follow suit. As of March 2025, no GM or GEd wheat is commercially grown in Australia. The rate at which private industry integrates GM and GEd into wheat breeding programmes will depend on several factors, including the regulatory consistency governing GM and GEd crops within Australia and among international trading partners, the return on investments relative to deregulation costs including licensing, the level of acceptance amongst growers and consumers, and technical considerations including wheat's amenability to tissue culture. This review contextualizes GM and GEd applications in wheat, often drawing on examples from crop species where biotechnology has been more widely employed, and considers the key stakeholders that will shape the future of GM and GEd wheat in Australia.

Plasticity in resource allocation can be beneficial for plants under stress. In savannas, tree-grass competition forces tree saplings growing in the grass layer to compete for water, nutrients, and light. Savanna tree saplings are also vulnerable to fire and herbivory, which may favour investment in storage belowground to support regrowth aboveground. It is unclear whether carbon (C) limitation from grass shading similarly favours allocation belowground. Further, investigating how light reduction changes allocation by juvenile trees to above- and belowground biomass, storage, and defence can help us understand juvenile tree allocation strategies during ubiquitous C limitation. Using a screenhouse experiment, we evaluated the effects of shade on carbon allocation and leaf physiology in saplings of a dominant ant-acacia, Acacia (Vachellia) drepanolobium. We hypothesized that shade would induce greater belowground allocation by saplings to root growth and storage. Indeed, we found that shaded saplings had higher root mass fractions and higher concentrations of starch in their roots than plants in full sunlight. Plants in full sunlight, meanwhile, invested more in aboveground growth, with higher stem mass fractions than shaded plants. Shade did not affect leaf mass fraction, but plants in the shade had a lower leaf mass per area, higher stomatal conductance, and a higher maximum photosynthetic rate, indicating leaf-level adjustments that increased carbon capture under light limitation. These responses are consistent with possible adaptive allocation strategies that buffer the impacts of fire and herbivory, underscoring the essential role of belowground reserves for regrowth.

Wild barley (Hordeum vulgare subsp. spontaneum), the progenitor of cultivated barley, is an invaluable genetic resource for enhancing crop resilience, particularly in drought-prone regions. Its natural adaptation to water-limited environments makes it an ideal candidate for studying mechanisms of drought tolerance. This study aims to investigate the genetic basis of drought tolerance by examining the correlation between molecular markers and root traits across a diverse collection of wild barley genotypes. This study evaluated the relationship between molecular markers and root traits in 114 wild barley genotypes collected from the natural distributional range in western Iran. The genotypes were subjected to normal (90%-95% field capacity) and water-stress (50%-55% field capacity) conditions. Root, physiological and seedling traits were carefully measured, and the genotypes were analyzed using 35 molecular markers, including simple sequence repeats (SSRs) and expressed sequence tag-SSRs (EST-SSRs). Statistical association analyses were performed to assess the correlation between markers and root traits. The study revealed significant genetic diversity among the 114 wild barley genotypes, reflecting distinct environmental pressures in their regions of origin. Several molecular markers, especially BMAG0603 and GBM1126, consistently exhibited strong associations with desirable root traits, such as increased root length, root density, and seedling vigor under both normal and water-stressed conditions. These markers are valuable for marker-assisted selection (MAS) in breeding programs aimed at improving drought tolerance. Specific chromosomal regions critical for root trait development were identified, offering insights into the genetic control of drought tolerance in barley. The results highlight the importance of using molecular markers to enhance drought tolerance in barley. The identification of key markers associated with beneficial root traits offers a valuable resource for breeding programs focused on drought resilience. Further research should explore marker-trait associations under various stress conditions to optimize the genetic potential of wild barley for crop improvement strategies.

Drought stress can affect the growth of soybean seedlings because soybeans require a large amount of water for growth and development. However, the storage and redistribution of water in the soil are related to the soil's texture. This experiment used the soybean varieties hefeng46 and heinong84, and studied the effects of four moisture conditions on the content of membrane lipid peroxides, the activities of enzymes and non-enzymatic antioxidants the content, and also the key enzymes of carbon and nitrogen metabolism in soybean seedlings under loamy sand and sandy loam soil conditions. The results suggested that as the duration of drought increased, in loamy sand, under serious drought (SD), the contents of malondialdehyde and proline, as well as the activities of superoxide dismutase and glutamine synthetase, in hefeng46 and heinong84 were significantly increased by 160% and 146%, 1431% and 1924%, 167% and 282%, and 64% and 69%, respectively, compared to the normal water (CK). However, in sandy loam, the hydrolytic direction activity of sucrose synthase in intermediate drought treated hefeng46 and heinong84 was significantly increased by 1247% and 169% compared to the CK, and the content of reduced glutathione was dramatically raised. In contrast, the synthetic direction activity of sucrose synthase in SD treated hefeng46 and heinong84 was significantly decreased by 69% and 70% compared to the CK. The combined results indicated that under drought stress, soybean in sandy loam soil exhibited stronger drought resistance.

Hybrid speciation is increasingly being recognized as an important driver in diversification. Of the two forms of hybrid speciation, polyploid hybrid speciation is considered more common as it provides instant reproductive isolation either completely or partially, due to meiotic incompatibilities with the parental species. Homoploid hybrid speciation is considered rare, as it lacks the instant reproductive isolation conferred by polyploidy, though there are an increasing number of examples in the literature. Reproductive isolation in the nascent homoploid hybrid species is commonly achieved by niche divergence, often into territory with one or more forms of abiotic stress unsuitable for parental species. However, reproductive isolation may be due to factors beyond mere niche divergence. In this paper, I examine the pollen fertility of hybrids compared with their parental species. Using a dataset of over 2000 observations, I compared F1 and F2 hybrids to members of the same genus and family. F1 hybrids universally have lower mean fertility than good species in their group at both the genus and family levels, and most of those differences are significant. Data for F2 hybrids are limited and conflicting, but there may be a path to restored fertility across multiple generations such as through fertility restoration genes or selection for increased fertility. Alternatively, homoploid hybrids may rely on forms of asexual reproduction. Examples exist to support both alternatives. While pollen fertility is a useful metric, other metrics of plant fertility could also throw light on the difficulty of forming a homoploid hybrid species in plants.