AoB Plants最新文献

Climate change is intensifying droughts across the globe, challenging species to adapt to novel conditions. While plant physiological and phenological responses to drought are well-documented, less is known about how water scarcity affects the evolution of selfing across species ranges. According to the selfing syndrome hypothesis, in environments where selfing confers a fitness advantage, selection should favour floral traits associated with increased selfing relative to outcrossing. We used a field experiment near the northern range edge of the scarlet monkeyflower (Mimulus cardinalis) to test this hypothesis both spatially (among leading-edge, central, and trailing-edge populations), and temporally (between cohorts separated by a period of historic drought). Although populations from different range positions showed genetic differentiation in some floral traits, these differences did not consistently support predictions of the selfing syndrome hypothesis. Contrary to the predictions of reduced investment in floral rewards and increased selfing ability at range edges, the sugar content of nectar was greater and autogamous seed set was smaller in leading-edge than central populations, herkogamy tended to be greater in trailing-edge populations relative to leading-edge and central ones, and nectar volume did not vary predictably among regions. There was no support for the evolution of selfing syndrome from the predrought ancestors to the postdrought descendants. Instead, in leading-edge populations, descendants evolved greater sugar content relative to ancestors, and there were no other differences between ancestors and descendants in any other trait or region. Overall, these findings suggest that mating system evolution in M. cardinalis likely reflects a complex interplay of regional factors including range position, historical adaptation, and local environmental variability, rather than simple stress-induced shifts towards selfing.

Salinity is one of the most devastating abiotic stresses limiting crop productivity. Here, the salinity tolerance level and physiological changes in Echinochloa frumentacea in saline and alkaline soils were estimated by studying root morphology, quantifying ions (Ca²⁺, K⁺, Na⁺, Ca²⁺/Na⁺, and K⁺/Na⁺) in roots, and measuring antioxidant enzyme activities, malondialdehyde (MDA), proline, and soluble sugar contents. Echinochloa frumentacea was tested against four neutral and alkaline salts, NaCl: Na₂SO₄:NaHCO₃:Na₂CO₃ in different proportions at 60, 120, 180, 240, and 300 mmol L^-1 concentrations. Echinochloa frumentacea was evaluated and compared with plant species, which are commonly cultivated in non-saline and alkaline soils i.e. Echinochola crusgalli, Avena sativa, Salicornia europaea, Medicago sativa, and Glycyrrhiza uralensis. The results revealed an increase in root length, diameter, absorption area, fresh, and dry weight at 120 mmol L^-1. However, a gradual decrease in these parameters was observed at higher salt concentrations. In contrast, an increase in superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) activities, and MDA and proline levels were observed with increasing salt concentration. The roots of E. frumentacea absorbed higher levels of ions than the other five forage plant species. Higher K⁺/Na⁺ and strong root structure in E. frumentacea indicate its better tolerance in saline soil than in alkaline soil. Our results demonstrate that E. frumentacea can tolerate up to 120 mmol L^-1 salt in a saline-alkaline environment and is more suitable for growth in saline soil. In addition, the root system of E. frumentacea can be used to dechlorinate the chloride from soil and reduce its toxic effect on plants. It can also be used as a target species for selection and breeding programs to improve salt tolerance in future studies.

Plant-plant interactions play a crucial role in shaping the growth environment for crops, impacting their productivity and resilience to stress. Interactions between plants have been incorporated into breeding programmes by selecting new target traits that will advance plants' abilities to produce in high densities. The study of plant-plant interactions belowground promises new pathways and traits for crop improvement. This study focuses on the developmental and physiological responses of sorghum (Sorghum bicolor L.) genotypes to neighbouring sorghum plants. In this study, we used two growing methods: (i) a focal plant surrounded by neighbouring plants in the same pot but without shading, and (ii) a focal plant grown either alone or surrounded by neighbours, irrigated with nutrient solution that was passed through pots (leachates) with or without plants. Our results show that the presence of neighbours in the same pot led to reduced dry weight, plant height, and leaf area of the focal plant. In addition, the presence of neighbours reduced stomatal conductance and photosystem II quantum yield. While the response direction was similar across tested genotypes, the magnitude varied. The results were repeated when neighbouring plants were not grown in the same pot, but a nutrient solution was passed through the root systems of other plants into a separate pot containing another plant. Furthermore, we saw a reduction in assimilation rate and stomatal conductance when plants were exposed to either the physical presence of neighbours or leachate. We did not find differences in root architecture in either treatment. These results show that plants change their growth in response to neighbours and that the signal is carried through the liquid phase of the soil. Our findings provide insights into sorghum plants' responses to belowground signalling from neighbouring plants and lay the foundation for future studies enabling increased crop performance under high-density planting conditions.

Eco-evolutionary optimality (EEO) theory predicts that plants maximize resource investment in photosynthetic capacity at the lowest costs of acquiring and using such resources. However, current EEO-based models predict photosynthetic capacity based on climate alone, and omit costs for resource acquisition. To explore the link between leaf-level optimality and plant-level nitrogen acquisition costs across different soil environments, we grew two commonly co-occurring species in a greenhouse under three nutrient fertilization levels in sand and two natural soils with matching nutrient availability to the fertilization levels in sand. At the end of the experiment, we measured the maximum rate of Rubisco carboxylation (V _cmax), δ¹³C-derived leaf-to-air CO₂ partial pressure ratio (c_i /c_a ), and structural carbon costs for nitrogen acquisition. Increasing nutrient availability increased V _cmax (P < .001) and decreased carbon costs for nitrogen acquisition (P < .001), similarly in sand and natural soils (P > .1 for both). Yet, the leaf c_i /c_a remained unchanged across treatments in sand (P = .426) and natural soils (P = .499), consistent with the current EEO-models assumption of climate-dependent optimality. These findings support the general principle that nutrient scarcity increases acquisition costs, while also highlighting a gap in current model formulations that neglect nutrient effects on photosynthetic acclimation.

Leaf trichomes in plants act as the first line of physical defence against herbivory, in addition to many other reported functions. Although trichomes have been found to vary intraspecifically and can be induced by herbivory, their interactive effects under additional factors, such as plant age and abaxial vs. adaxial leaf surfaces, are less understood. Here, using five common tomato varieties, we explored the effects of these factors and their interactions on trichome type and density. We quantified the densities of Type VI glandular trichomes, non-glandular trichomes, and total trichomes on abaxial and adaxial leaf surfaces, and total leaf trichomes with and without herbivory by Spodoptera exigua at both vegetative and reproductive stages. Further, we also tested whether the time taken to initiate feeding by S. exigua larvae could be influenced by the number of trichomes on the adaxial and abaxial surfaces. The results showed that there is significant variation in trichome density among varieties and leaf surfaces. Also, there were differences in herbivory-induced trichome production, with variable responses across varieties and growth stages. Bioassay results showed that insects took longer to initiate feeding on the abaxial leaf surface than on the adaxial surface, potentially due to the higher density of non-glandular trichomes on the abaxial side. Collectively, we report that the regulation and development of trichomes on the leaf surface of tomatoes is governed by multiple factors, with potential consequences for herbivore feeding, suggesting how physical defences play a significant role in insect-plant interactions.

Papaver somniferum (poppy) is a traditional ingredient in Central and Eastern European cuisine and an important oilseed crop of the region. Since the main threat to stable poppy yield is pathogen infection, a detailed understanding of its defence mechanism is essential. The first robust layer of plant immunity, which plays a crucial role in combating pathogens, is pattern-triggered immunity (PTI). Here, we provide the first comprehensive insights into PTI in poppy. We selected four poppy varieties used in the food industry and investigated their response to various previously described peptide elicitors. Among all tested peptides, flg22 induced the most robust reactive oxygen species (ROS) burst, as well as triggering putative mitogen-activated protein kinase phosphorylation and seedling growth inhibition in all selected cultivars. We identified PsWRKY22 and PsPR2 as candidate marker genes suitable for monitoring poppy PTI responses. The tested poppy cultivars have low levels of salicylic acid. Callose accumulation was triggered by wounding but not by flg22. When studying PTI in plants, wounding is a challenge that needs to be considered, as it can obscure potential PTI responses. Our findings highlight conserved aspects of poppy immunity and the challenges of studying its PTI. The established pipeline facilitates improving our understanding of poppy immunity and has the potential for widespread application in breeding and improving selection for broad-spectrum disease resistance provided by enhanced PTI.

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.

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.