Speciation arises from multifaceted factors, making phenotype-based classifications unreliable. Integrative taxonomy has advanced significant breakthroughs in taxonomically challenging groups like Apiaceae, which is characterized by highly convergent morphological traits across species. The genus Eriocycla (Apiaceae) has long presented persistent taxonomic uncertainties. While morphological similarities initially supported Eriocycla as Seseli sect. Eriocycla, phylogenetic studies consistently resolve Eriocycla within the tribe Echinophoreae, contrasting with Seseli (tribe Selineae). Integrated morphological and molecular analyses were conducted here to resolve this taxonomic conflict. Phylogenetic reconstructions based on nuclear ribosomal DNA and plastomes all supported that Seseli delavayi and Seseli nortonii formed a stable monophyletic group with Eriocycla nuda and Eriocycla pelliotii within Echinophoreae, separate from Seseli. Plastome comparisons across 14 taxa revealed structural conservation in E. nuda, E. pelliotii, S. delavayi, and S. nortonii, particularly in inverted-repeat and single-copy regions, distinct from that of other Seseli species. A unique inversion involving the trnY–GUA, trnD–GUC, and trnE–UUC genes was detected in E. nuda and E. pelliotii but absent in S. delavayi and S. nortonii. Shared morphological characteristics, including glabrous stem bases, basally free bracteoles, and prominent calyx teeth, further support their affinity with Eriocycla. We therefore propose to recognize Eriocycla as a separate genus rather than as Seseli sect. Eriocycla and reclassifying S. delavayi and S. nortonii into it. In conclusion, this study not only revealed the phylogenetic position of the tribe Echinophoreae but also resolved the long-standing taxonomic controversy surrounding Eriocycla and Seseli.

High-temperature events are projected to increase in frequency under future climate scenarios, threatening rice yields globally. This study investigated the physiological and molecular responses of two Brazilian flooded rice varieties, IRGA 428 and BR-IRGA 409, during the anthesis stage under high-temperature stress, aiming to uncover mechanisms of heat tolerance. Plants were exposed to a daytime temperature of 38°C for 7 h across 3, 5, or 7 days. Prolonged heat stress led to a significant reduction in filled grain in both cultivars, although BR-IRGA 409 demonstrated greater heat tolerance, particularly under 3 days of stress, as it maintained higher spikelet fertility compared to IRGA 428. Comparative transcriptome analysis revealed that BR-IRGA 409 had more differentially expressed genes in response to heat stress, including a significant upregulation of canonical heat-responsive genes such as heat shock factors, heat shock proteins, and peptidyl-prolyl isomerase FK506-binding proteins (FKBPs). Furthermore, BR-IRGA 409 displayed enhanced modulation of the mitochondrial electron transport pathway, which is crucial for adenosine triphosphate (ATP) synthesis and cellular energy production. Interestingly, while photosynthetic performance varied between cultivars, only a few genes associated with photosynthesis were significantly altered in response to heat stress. Instead, BR-IRGA 409 displayed a higher basal expression of photosynthesis-related genes, suggesting that this pre-adaptation might mitigate heat stress impacts on photosynthesis. The ability to preserve functional photosynthetic activity is critical for sustaining the energy-intensive process required to cope with heat stress. This study highlights the difference between the varieties in their response to heat stress and identifies candidate molecular and physiological mechanisms that contribute to maintaining cellular energy homeostasis and heat tolerance in Brazilian rice, providing valuable insights for crop improvement strategies.

Woody plants with green stems may have advantages over non-green-stemmed plants in that extra photosynthetic carbon gain has the potential to improve plant drought tolerance and aid drought recovery. However, most studies relating to green stem photosynthesis and drought tolerance have been conducted on non-horticultural plants under natural growing conditions. We investigated whether avocado green stem photosynthesis enhances drought tolerance and recovery. We applied light exclusion and drought treatments to 3-year-old potted trees of cultivars ‘Hass’ and ‘Fuerte’. Measurements of soil moisture, midday stem water potential, stem photosynthesis, bark chlorophyll concentration, concentration of sugars + starch and stem hydraulic conductivity were conducted before, during, and 3 weeks after rewatering. Green stems of avocado re-assimilate CO2, but values did not significantly differ between cultivars. We also found that light exclusion reduced stem photosynthesis by 65% in ‘Fuerte’ and 30% in ‘Hass’ although bark chlorophyll concentration was unchanged. Drought reduced stem photosynthesis by 60%. Following drought recovery, there were neither treatment nor cultivar effects on stem photosynthesis. We also observed no effect of light treatment on hydraulic conductivity, such that there is no clear effect of stem photosynthesis on drought tolerance of these avocado trees. However, we observed an increase in hydraulic conductivity during the drought period with an increase in the concentration of sugars in the sapwood and a decrease in the concentration of starch, suggesting osmotic adjustment. Nonetheless, the contribution of carbon gain through stem photosynthesis may not play a significant role in hydraulic functioning of avocado under these 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.

To cope with heat and water stress, evergreen and deciduous species from hot and arid deserts should adjust their stomatal conductance (gs) and leaf water potential (Ψleaf) regulation in response to changes in soil water availability, high temperatures, and vapour pressure deficits (VPDs). To test whether phenology induces changes in gs–Ψleaf coordination, we tested for associations between 14 leaf traits involved in leaf economics, hydraulics, and stomatal regulation, including minimum seasonal water potential (Ψmin) and maximum gs (gsmax), turgor loss point (Ψtlp), osmotic potential (Ψo), leaf area (LA), and specific leaf area (SLA), across 12 tree species from the Sonoran Desert with contrasting phenology. We found that foliar phenology, leaf hydraulics, and leaf economic traits are coordinated across species and organized along the axis of physiological efficiency and safety in response to temperature and VPD. Evergreens were more drought-tolerant and more restrictive in water use than deciduous species, maintaining lower gs during the rainy season and lower Ψmin, Ψo, and Ψtlp. In contrast, deciduous species were less drought-tolerant, shedding their leaves during the dry season. During the rainy season, they exhibit higher gs than evergreens, enhancing water transpiration. Moreover, deciduous species, as isohydric plants, showed stricter control over gs and finer regulation of leaf water potential (Ψleaf). Due to their remarkable physiological diversity, desert trees can endure extreme environmental conditions by employing contrasting hydrological strategies.

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.

Cowpea [Vigna unguiculata (L.) Walp] is more drought tolerant than other legumes, although drought still limits its productivity. Under drought stress, cowpea closes its stomata more rapidly to maintain its plant water content than soybean. The rapidly stomatal closure under drought stress in cowpea is mediated by abscisic acid (ABA), but the details of the mechanism are not yet clear. We examined the expression of an ABA-biosynthesis-related gene encoding 9-cis-epoxycarotenoid dioxygenase (NCED) and ABA content in roots of cowpea and soybean under drought stress. Following an analysis of each NCED gene's promoter, we investigated the expression of the genes for WRKY transcription factors VuWRKY57 and GmWRKY32. NCED gene expression conformed with VuWRKY57 and GmWRKY32 expression, and VuWRKY57 bound to the VuNCED1 promoter. Overexpression of VuWRKY57 in Arabidopsis confirmed the drought stress tolerance. Thus, under drought stress, VuWRKY57 expression is rapidly induced in cowpea roots; ABA content increased via the induction of VuNCED1 leads to stomatal closure; and drought tolerance is conferred.

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.

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.