Gene-editing tools enable precise, targeted genome modifications, providing new approach for the rapid and sustainable improvement of tea plant (Camellia sinensis (L.) Kuntze). Developing such an approach is especially important due to the perennial nature and complex genetics of the tea plant, which make traditional breeding slow and inefficient. To validate a gene editing protocol in the elite local tea cultivar Kolkhida three candidate genes were selected. Two guide RNAs (gRNAs) were designed for each gene, and corresponding constructs for targeted genome modification in tea were generated. Successful modifications of the target sequences in cv. Kolkhida tea protoplasts were achieved for all three target genes. The high mutagenic efficiency of the selected gRNAs was observed for two out of three genes, including induction of precise deletions between target motifs. gRNAs were delivered in protoplasts via co-transfection technique, and combined gRNA activity was observed when transfection efficiency exceeded 28%. The genome modification method for tea protoplasts established in this study can serve as a screening protocol to evaluate the in vivo efficiency of different genome editing approaches in the tea plant.

The study of floral biology has long attracted the attention of plant biologists because of its enormous basic and applied implications, spanning from identification of the ecological and genetic drivers of flowering plant evolution to the performance of crop yields in agricultural systems. In a rapidly changing planet, floral biology studies acquire an utmost importance to comprehend the multiple ecological, economical, and social challenges ahead for humanity. In this special issue, we gathered a collection of papers dealing with various ecological, genetic, and evolutionary aspects of floral biology. This special issue encompasses 12 papers showcasing theoretical and empirical research on plant–pollinator communities, pollinators and pollination modes, floral ecology and genetics at various spatial scales, and the effects of warming-induced abiotic stress on floral biology. Overall, this special issue highlights the importance of long-term spatial and temporal studies, which require a collaborative effort of the research community, and the development of experimental approaches to quantify in detail the effects of human-induced abiotic stress, such as droughts and heatwaves, on plant reproduction.

Pearl millet and finger millet face challenges in adopting transgenic or editing approaches due to their inherent recalcitrance to genetic transformation protocols. To overcome these limitations, the current study aims to streamline the genetic transformation protocol for pearl millet and finger millet. We targeted mature embryos as explants to assess transformation efficiencies, gain in time, and overall feasibility. Notably, a transformation efficiency of 17.74% and 18.79%, for pearl millet and finger millet, respectively, was observed using a method that involved directly piercing the mature seeds at the embryonic region with a needle dipped in Agrobacterium suspension, followed by vacuum infiltration. After infection, the seeds were allowed to produce calli and differentiate into shoots and roots, resulting in the development of PCR-positive plants. The induction of infected explants to form calli and subsequent differentiation into shoots and roots, leading to putatively transformed plants, was achieved within 60–66 days. Chi-square analysis of hygromycin selection in T1 progeny showed a 3:1 segregation, indicating single-locus inheritance, and PCR of T1 plants with Cas9 and HptII primers confirmed intact T-DNA transmission. Furthermore, as a proof-of-concept for transformation leading to gene editing, a grain-specific phospholipase-d delta1 (PgPLD-delta1-7a), previously identified in our study, was successfully targeted in pearl millet using the CRISPR/Cas9 approach. This seed-piercing protocol has been successfully evaluated in two genotypes of pearl millet and one genotype of finger millet, resulting in the generation of putative-transformed plants.

Stomata, the gatekeepers of leaf gas exchange, regulate carbon dioxide uptake and water loss, functions increasingly critical as crops face more frequent, intense heat and drought. Under dry conditions, stomatal conductance (gs) typically decreases, limiting carbon assimilation and yield. Heat stress, in contrast, elicits variable gS responses: sometimes increasing to facilitate transpirational cooling, while at other times decreasing, especially when combined with drought. Heat and drought also induce complex, context-dependent shifts in stomatal anatomy. Smaller, denser stomata improve drought resilience in some cases, while reduced density confers greater tolerance in others. The optimal stomatal ideotype remains unknown, and different or even opposing traits may confer resilience dependent on the environmental scenario. Substantial genotypic variation in gs and stomatal anatomy, high heritability and co-localized quantitative trait loci for stomatal traits and yield highlight their untapped potential as breeding targets for climate-resilient crops. However, stomatal traits remain largely absent from breeding pipelines due to challenges of phenotyping at scale. This is changing rapidly. Advances in deep learning, porometry, digital microscopy, and remote sensing now enable high-throughput measurement of stomatal physiology and anatomy. Next-generation breeding technologies including clustered regularly interspaced short palindromic repeats (CRISPR), multi-omics approaches, and artificial intelligence-driven ideotype selection models could revolutionize breeding, allowing precise engineering of stomatal traits for resilience to environmental stress. The time has come to move beyond characterizing stomatal traits and start actively incorporating them into breeding strategies. By leveraging these technologies, stomatal traits can become high value targets, unlocking their potential to enhance crop performance in a hotter, drier future.

Habitat loss and fragmentation directly influence plant genetic diversity and how it is spatially structured. Species associated with shrinking habitats generally experience population declines and genetic erosion, potentially increasing extinction risk. An endangered North American habitat, the oak savanna, supports high plant biodiversity and is the primary habitat for sundial lupine (Lupinus perennis L.). This legume serves as the primary host plant for several highly specialized insects. Sundial lupine is declining in the eastern part of its range, and restoration efforts lack an understanding of the regional level of population differentiation in this species. In this study, we addressed this gap by characterizing the population genetic structure and levels of inbreeding of sundial lupine with nine microsatellite markers across 25 populations throughout its distribution. To assess whether losses of genetic diversity are impacting population fitness, we investigated whether germination rates were associated with within-population genetic diversity and inbreeding. Genetic diversity was greatest in the southernmost population (Florida). We found significant differentiation between populations (pairwise GST ranging from 0.003 to 0.63) and identified five genetic clusters with high levels of admixture. No sites showed significant levels of inbreeding (FIS; mean −0.01, standard deviation 0.15). Germination success did not differ based on population size but decreased in populations with negative inbreeding coefficients. Our data suggest that there are significant levels of admixture between populations; thus, it is possible to use seeds from multiple sources for restoration. Still, due to the widespread distribution of sundial lupine, it is possible that populations may exhibit local adaptation to regional aspects of their habitat, and we caution against long-distance movement between populations.

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.

Examining long-term trends in climate-driven flowering time shifts provides valuable insights, but can mask dynamic interannual variation that may reveal the capacity for short-term phenological responses. We examined the interannual and intraspecific dynamics of flowering time shifts in Triodanis perfoliata (Campanulaceae) using a comprehensive dataset with a total 1493 vetted records spanning 1895–2022 across the contiguous USA. Here, we build on previous work demonstrating long-term flowering time advances (Berg et al., An examination of climate-driven flowering-time shifts at large spatial scales over 153 years in a common weedy annual. Am J Bot 2019;106:1435–43.). Specifically, we examined the influence of interannual temperature variation on flowering time, and explored how these responses varied across a broad geographic range. We found a significant correlation between interannual spring temperature variation and flowering time, with cooler springs associated with delayed flowering and warmer springs associated with earlier flowering. Critically, we found that the magnitude of this relationship varied among T. perfoliata populations, with individuals in cooler, higher latitude regions showing less sensitivity to interannual temperature variation than those in warmer, lower latitude regions. This differential sensitivity suggests potential adaptive or plastic responses to local climatic conditions and may have implications for gene flow and the long-term ecological and evolutionary trajectory of T. perfoliata populations. This study highlights the importance of considering both long-term trends and interannual variation in phenological research, and emphasizes the need for further investigation into the drivers and consequences of intraspecific variation in phenological sensitivity.

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 (Ψl) declined under imposed drought. We also examined whether water stress could trigger late leaf development. At high Ψl 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 Ψl 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.

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.