AoB Plants最新文献

Increasing frequency and intensity of global warming pose a profound threat to plant species persistence. Most investigations on plants' resilience to heat events focus on few genotypes of model species. Novel insights into resilience mechanisms will be gained by focusing on natural variation in thermotolerance and its relationship to local-abiotic factors. Additionally, studying species that survived 'ancient periods' of high temperatures provides insight into resilience mechanisms. Within a species, we assessed spatial thermotolerance variation, its association with temperature and light, while testing for thermotolerance sex differences and its relationship with population sex ratios. We used Marchantia inflexa, a species with unisexual individuals exhibiting spatial variation in physiologies and life histories. To assess field basal thermotolerance (field BT), we examined the efficiency of photosystem II recovery following a heat treatment (53°C for 45 min) in over 200 field-collected plants from seven sites. We further examined whether field BT is linked to initial physiological traits or environmental factors and assessed its potential as a predictor of sex ratios. Following the heat treatment, plants exhibited damage and were still recovering by day ten; recovery was generally higher in road- relative to stream-collected plants with notable variation among sites. Thermotolerance was positively associated with light and tended to be negatively associated with temperature. This light-thermotolerance relationship was more pronounced in males, and thermotolerance differences between females and males tended to be positively related to the proportion of females. The positive light-thermotolerance association suggests that light is a key factor driving heat stress resilience in M. inflexa. The light-thermotolerance relationship for males vs. females implies sex-specific strategies for coping with abiotic stress. There were subtle thermotolerance impacts on population sex ratios. These insights broaden the understanding of the thermotolerance diversity present within a species.

Plants have long-lasting and complex interactions with herbivores, including insects and mammals. In response to high herbivory rates, plants either tolerate biomass loss or develop several defence mechanisms, such as physical defence. The resource availability hypothesis (RAH) predicts that plant defence investment is dependent on resource availability and plant's life history. However, the effect of resource availability on plant investment in defence is mediated through biotic pressure. We tested the effects of soil qualities and browsing pressure on the physical defence and reproductive investments in Acacia sieberiana at the Pendjari Biosphere Reserve in West Africa. We selected six populations, including three in the Pendjari River floodplain where soil moisture is high but with high elephant browsing pressure, and three populations on the plateau in the hunting zone where soils are drier and relatively poorer with a lower density of elephants. We found greater investment in physical defence for trees in the floodplain. Furthermore, A. sieberiana trees produced less fruit in the floodplain than in the plateau. Contrary to the predictions of the RAH, we found more and longer thorns in populations in the richer floodplains than on the plateau. This was linked to higher elephant browsing pressure in the floodplains. This physical defence was probably induced to cope with the episodic but high levels of herbivory observed in this environment. Surprisingly, the negative influence of thorn number and size on the likelihood of elephant damage was observed only in the rich floodplains and not in plateau sites. Altogether, our study demonstrates that the influence of resource availability (soil moisture, pH, and fertility) in shaping plant physical defence can be outweighed by high herbivory pressure.

The genus Larrea has an amphitropical distribution in North and South American deserts, and its phylogeny remains unresolved. This genus is conspicuous and specious within the Monte Desert, the largest, although understudied, southern South American dryland. Larrea presents an interesting case for phylogenetic studies due to its paternally inherited chloroplasts, its species hybridize in nature, and although nominal species are morphologically distinct, hybrids might be cryptic. We analysed ITS2 nuclear (nDNA) and rbcL chloroplast (cpDNA) sequences of the bifoliolate section, Bifolium, including L. tridentata (Lt) from North America, and its South American congeners: L. cuneifolia (Lc) and L. divaricata (Ld), and sequences of the multifoliolate Larrea section: L. ameghinoi (La), L. nitida (Ln), and a morphological hybrid swarm. We aligned and analysed sequences from 111 individuals collected at 31 populations sampled along the range of each species. The nDNA revealed 56 haplotypes, and median-joining and maximum likelihood reconstructions provided clear separation among species and suggested hybridization between Lc-Ld. The nuclear phylogeny showed that the section Larrea diverged earlier than Bifolium, within which Lc diverged first, meanwhile, consistent with previous studies, Lt forms a monophyletic group sister to Ld. Comparatively, cpDNA was less variable, with only six haplotypes shared between Ln-Lc and Ln-La, and rarely between Ld-Lc. Our results emphasize the significance of separately considering nuclear and plastid evolutionary signals when reconstructing unresolved relationships. While nuclear markers clarified phylogenetic relationships and cryptic hybridization among Larrea species, the chloroplast revealed the retention of widespread ancient polymorphisms, which were conserved in populations of distinct species. Each marker provided insights into particular evolutionary patterns, highlighting that genetic variation may be more influenced by hybridization and mode of chloroplast inheritance than previously recognized.

Previous systematic studies have generated abundant information on plants in family Onagraceae Juss., making this taxonomic group a model for understanding plant evolution. The chloroplast genome is widely used to provide valuable insights into how plant lineages evolved. In the present study, we employed shotgun sequencing to assemble new plastomes from Onagraceae. Plastomes of ten species and one genus, Fuchsia, are reported for the first time. We characterize and compare the plastome features of six genera (Chamaenerion, Circaea, Epilobium, Fuchsia, Ludwigia, and Oenothera), allowing us to reconstruct their phylogenies and explore inter- and infra-generic evolutionary relationships, inverted repeat (IR) expansion, plastome size increases, and correlations among repeat elements, genetic variations, and evolutionary events. Our findings indicate that each of the tribes and subfamilies we assessed exhibits unique plastome features. Our phylogenetic tree supports previous findings, but also reveals that some clades need further systematic analyses. We show that increased plastome size within subfamily Onagroideae coincides with IR expansion, which is not the case for subfamily Ludwigioideae. In addition, our results indicate that higher repeat numbers and greater genetic variation can serve as indicators of evolutionary events, such as gene loss and gain, IR boundary shifts, and inversions, but they may not have arisen universally across all members of Onagraceae. Our study provides some novel insights into plastome evolution in the Onagraceae. Further studies should aim to elucidate how plastome size has evolved in Ludwigioideae and explore the evolutionary roles of regions in Onagraceae plastomes exhibiting high repeat numbers and genetic variations.

Plant diversity is critical to ensure the future of humanity, as it provides essential ecosystem services and functioning. As recent estimates showed that animal-mediated pollination is crucial for the reproduction of approximately 90% of flowering plants, playing an essential role in maintaining biodiversity and agricultural productivity, effort to preserve plants cannot be disjoined from pollinator conservation initiatives. Despite their importance, pollinators have experienced alarming declines. The LIFE 4 Pollinators project was launched to involve people protecting wild bees and other pollinators in the Mediterranean. This study presents data collected through the project's web-platform, where users uploaded over 2,000 photographs of plant-pollinator interactions between 2021 and 2024. The dataset focuses on the identification of flower-visiting insects and plants, and the current study gives emphasis to citizen scientists' ability to identify plants and pollinators. 1,407 photo-records were analysed, revealing that bees and beetles were the most frequent pollinators, with plants of the Asteraceae and Cistaceae families being the most recorded. Users correctly identified 93.7% of insect taxonomic aggregations and 74.2% of plant species. The study also highlights the recording of threatened, alien, and invasive species, including the vulnerable Callicera spinolae and the invasive Vespa velutina. The plant-pollinator network analysis supports the floral syndrome concept, with floral morphologies like 'Head' and 'Disk' attracting a wide range of pollinators. The results indicate that citizen science contributes to the identification and monitoring of pollinators, generating knowledge that may be key to the conservation of these organisms and to better understand plant-pollinator interactions. Data collection through citizen-generated photographs allows to significantly expand the geographic area and the magnitude of studies, facilitating large-scale analyses that would be difficult to achieve with traditional monitoring methods. These findings provide a useful basis for future conservation initiatives and the development of policies aimed at mitigating pollinator decline.

Leaf veins hydrate and sustain leaf tissue for photosynthesis. During drought and freeze events, embolisms can form in xylem conduits, ceasing the transport of water. Understanding the formation and propagation of embolisms is crucial to predicting species' responses to a changing climate. We develop a novel spatio-temporal model for embolism propagation, explore the dynamics of xylem cavitation through spatial survival analysis modelling, and quantitatively examine the relationship between leaf venation features and embolism propagation. Our work models embolism propagation through spatial survival modelling, allowing us to compare the importance of different factors (vein thickness and spatial dependency) in embolism formation and predict future embolism occurrences. The model is fitted to published spatio-temporal embolism data for leaves of eight evergreen tropical tree species collected using the optical vulnerability technique. Results derived from our analyses shed light on the role of venation patterns on embolism formation. We found that incorporating spatial dependency reduces uncertainty in estimating vulnerability curves and posterior predictive error, thus supporting the notion that embolism formation exhibits spatial dependence. Specifically, the likelihood of embolism in a vein segment increases when adjacent veins are affected. Furthermore, including vein thickness information improves the prediction of future embolism events. Additionally, our model revealed that leaves with more connected vein networks (i.e. the degree of connectivity) exhibit a more pronounced pattern of embolizing from thicker to thinner veins. Understanding the formation and propagation of embolisms is crucial to understanding species' responses to a changing climate. The proposed model provides a statistical tool to extract quantifiable insights on embolism propagation and how it is associated with observable leaf features, such as network connectivity. This approach allows for a systematic assessment of species' responses to a drying climate.

To increase the cannabidiol (CBD) content of industrial hemp, male hemp was screened out by spraying cytokinin at the three-leaf stage of seedlings, and more female hemp was cultivated. 6-BA 60 mg·L^-1 treated female flowers of industrial hemp were subjected to transcriptomic, proteomic, and metabolomic analyses to investigate the changes and molecular mechanisms of gene expression and metabolites and related pathways of 6-BA in the development of female flowers of industrial hemp. The results showed that 1189 differentially expressed genes (DEGs), 168 differentially expressed proteins (DEPs), and 138 DAMs were screened compared with the control. Functional enrichment analysis revealed that phytohormone signaling, starch and sucrose metabolism, flavonoid biosynthesis, phenylpropane metabolism, and glutathione metabolism were the major pathways enriched, and differential genes, proteins, and metabolites enriched in the above pathways were further followed up and analyzed. It was found that, among them, CCL1, PAL1, and C4H were the key genes and proteins involved in the phenylpropane metabolic pathway, CYP450 and FLS were not only the upstream genes in the flavonoid biosynthesis pathway, but CYP450 were also involved in the synthesis of phytohormones and catabolism. FLS was related to the synthesis of saccharides. It was hypothesized that the carbohydrates might synergistically act with cytokinins to induce female flower differentiation in industrial hemp. The flavonoid biosynthesis pathway and glutathione metabolism pathway are also closely related to feminization. This paper provides a reference for subsequent studies on sex differentiation in hemp or other plants.

The duckweeds feature global distributions and diverse applications in phytoremediation and nutrition, as well as use in fundamental studies of development. Existing collections have minimal environmental data linked to natural habitats. Thus, there is a lack of understanding of natural variation in the context of native habitats. Here, a novel collection of 124 duckweed accessions from 115 sites across the United Kingdom was characterized by genome sequencing and ionomics. In common nutrient-replete experimental conditions, all accessions hyperaccumulated P, K, Mg and Ca. Local but not large-scale associations were revealed between elemental composition of duckweed in common, replete conditions and native water profiles. Lemna minor was the most prevalent species in the UK, with a closely related hybrid L. japonica frequently found in waters with higher micronutrient concentrations. Invasive L. minuta was common in the southern and midland regions, but restricted in Scotland. Lemna accessions accumulated heavy metal contaminants typically together with macronutrients, suggesting phytoremediation potential, but some limitations as food. Furthermore, monitoring the ecological interactions between native, hybrid and invasive Lemna species should be ongoing in the interest of biodiversity.

Mountain rye (MR: Secale strictum syn. S. montanum) is a forage grass that is considered a candidate for perennial grain development in Australia. A greater understanding of the triggers for flowering would aid the integration of this dual-purpose perennial into Australian grazing and cropping systems. The objective of this experiment was to determine the effects of cold incubation (vernalization) periods of varying duration on the grain yield, biomass production, and phenology of MR, compared to a dual purpose annual winter wheat cultivar (AW: Triticum aestivum L), and the perennial intermediate wheatgrass (IWG: Thinopyrum intermedium (Host) Barkworth & D.R. Dewey). Plants were grown in pots to a three leaf stage, before being subjected to vernalization treatments of varying length (0, 3, 5, 7, 9, and 11 weeks) using a growth chamber set to 5°C and 10 hour lighting. The plants were then transferred to a glasshouse set to 22°C and a minimum of 10 hour lighting. Glasshouse daylengths increased as the season progressed from winter into spring and summer. Exposure at ≤5°C for 5 weeks in MR optimized reproductive development, compared to approximately 3 weeks for winter wheat and 11 weeks for IWG. Both MR and IWG appear to have a dual induction requirement, needing a period of cold exposure and short days, followed by daylengths of 12-13 hours for MR, and at least 13 hours for IWG, to optimize their grain production potential. The observed higher vernalization requirement of MR, compared to AW, helps delineate the grain production potential of the tested germplasm in current wheat-growing areas of temperate Australia. Reproductive tiller percentages were much higher and developed earlier in AW compared to the perennial cereals. Improving the ratio and timing of reproductive tillers development in perennial cereals should be a target if grain yields are to be improved.

The flowering phenology of many closely related species in the Brazilian Cerrado coincides with the onset of the rainy season, where sequential flowering often occurs with some overlap. Transitioning from solitary flowering to coflowering with congeneric species may alter the pollination environment, affecting pollen delivery and deposition patterns. Coflowering among conspecifics concurrently requires pollination niche differentiation to minimize reproductive costs. This study tested these concepts in the distylous Palicourea coriacea during two flowering periods: early in the season when it flowered alone, and later with conspecific P. officinalis, also distylous. Pollination syndromes were assessed by measuring corolla length, nectar volume and sugar concentration, and reproductive organ height. Palicourea coriacea shows yellow and shorter corollas with higher sugar concentration in the nectar, while P. officinalis presents yellow to orange longer corollas with more diluted nectar, aligning with bee and hummingbird pollination syndromes, respectively, as reported in the literature. However, the species exhibited significant overlap in stigma and anthers height. The main floral visitor in the two species during the study was Bombus pauloensis. Visitation increased through the season, particularly in conspecific patches of P. coriacea, resulting in higher pollen delivery. In contrast, pollen deposition was similar or higher in congeneric patches with P. officinalis during the coflowering period. Visits to P. coriacea were higher than in P. officinalis, suggesting a bumblebee preference for the former. The study highlights the complex interplay between flowering phenology, floral traits, and pollinator behaviour in shaping reproductive outcomes and potential niche differentiation. While differences in flowering and flower morphology may prevent potential costs of pollinator sharing, the risk of reproductive interference remains significant. Future research should focus on comprehensive pollination dynamics throughout the entire flowering season, measuring pollinator behaviour, pollen dynamics and plant fitness, to further elucidate the mechanisms driving floral evolution and niche differentiation in sympatric species.