AoB Plants最新文献

Phosphorus (P) and potassium (K) play important roles in plant metabolism and hydraulic balance, respectively, while calcium (Ca) and magnesium (Mg) are important components of cell walls. Although significant amounts of these nutrients are found in wood, relatively little is known on how the wood concentrations of these nutrients are related to other wood traits, or on the factors driving the resorption of these nutrients within stems. We measured wood nutrient (i.e. P, K, Ca, and Mg) concentrations, wood specific gravity (WSG), as well as wood fibre and parenchyma fractions, in both inner (i.e. close to the pith) and outer (i.e. close to the bark) wood, for 22 tree species from a rainforest of eastern Amazonia. We first examined the associations of wood nutrient concentrations with WSG, fibre fractions, and parenchyma fractions. Then, we assessed whether resorption rates (i.e. difference between heartwood and sapwood nutrient contents) differed among nutrients, and whether nutrient resorption rates were related to species ecological strategies. WSG was unrelated to wood Ca, positively related to wood P in outer wood, and negatively related to inner wood Mg, as well as to both inner and outer wood K. Overall, nutrients were unrelated or negatively related to fibre and parenchyma fractions, except for wood Ca and wood P, which were positively related to fibre and axial parenchyma fractions in outer wood, respectively. We found that resorption rates did not differ among nutrients, and that P resorption rates were higher in high WSG, while K, Ca, and Mg resorption rates were unrelated to WSG. This study illustrates that the relationships of wood nutrient concentration with WSG and cell type fractions can be nutrient-specific. Our results indicate that, excluding a positive association between wood Ca and fibre fractions, and between wood P and axial parenchyma fractions, wood nutrients were mostly unrelated to anatomical traits. Our findings also suggest that high-WSG (i.e. shade-tolerant) species store higher amounts of wood P, and are more efficient at resorbing wood P, than low-WSG (i.e. fast-growing) species. These insights are important to increase our understanding on wood nutrient allocation, nutrient resorption, and tree ecological strategies in lowland tropical forests.

The shift from outcrossing to predominantly selfing is one of the most common transitions in plant evolution. This evolutionary shift has received considerable attention from biologists; however, this work has almost exclusively been focused on animal-pollinated systems. Despite the seminal ecological and economic importance of wind-pollinated species, the mechanisms controlling the degree of outcrossing in wind-pollinated taxa remain poorly understood. As a first step toward addressing this issue, we have conducted a comparative study of floral biology between two recently diverged sister species, Oryza rufipogon and Oryza nivara (Poaceae), that are wind-pollinated and possess distinct mating systems with O. rufipogon being outcrossing and O. nivara highly self-fertilized Therefore, these species present an ideal system for exploring mating system evolution in wind-pollinated taxa. We have identified key floral traits that differ between populations of these species and that are associated with mating system divergence including anther length, anther basal pore size, stigma papillae density, panicle shape, panicle exsertion, pollen viability, and early anther dehiscence. Of these traits, large anther basal pore size and early anther dehiscence are hypothesized to confer reliable autogamous selfing in O. nivara. Manipulations of floret number were conducted to partition the role of geitonogamy and autogamy in conferring self-fertilization. This experiment revealed that selfing in O. nivara is consistent with autogamous selfing, whereas O. rufipogon achieves selfing through geitonogamy. This study serves as a model for understanding the floral mechanisms controlling the outcrossing rate in other wind-pollinated systems, most notably other grasses.

Functional-structural plant (FSP) models are useful tools for understanding plant functioning and how plants react to their environment. Developing tree FSP models is data-intensive and measuring tree architecture using conventional measurement tools is a laborious process. Light detection and ranging (LiDAR) could be an alternative nondestructive method to obtain structural information about tree architecture. This research investigated how terrestrial LiDAR (TLS)-derived tree traits could be used in the design and parameterization of tree FSP models. A systematic literature search was performed to create an overview of tree parameters needed for FSP model development. The resulting structural parameters were compared to LiDAR literature to get an overview of the possibilities and limitations. Furthermore, a tropical tree and Scots pine FSP model were selected and parametrized with TLS-derived parameters. Quantitative structural models were used to derive the parameters and a total of 37 TLS-scanned tropical trees and 10 Scots pines were included in the analysis. Ninety papers on FSP tree models were screened and eight papers fulfilled all the selection criteria. From these papers, 50 structural parameters used for FSP model development were identified, from which 28 parameters were found to be derivable from LiDAR. The TLS-derived parameters were compared to measurements, and the accuracy was variable. It was found that branch angle could be used as model input, but internode length was unsuitable. Outputs of the FSP models with TLS-derived branch angle differed from the FSP model outcomes with default branch angle. Results showed that it is possible to use TLS for FSP model inputs, although with caution as this has implications for the model variable outputs. In the future, LiDAR could help improve efficiency in building new FSP models, increase the accuracy of existing models, add metrics for optimization, and open new possibilities to explore previously unobtainable plant traits.

Perennial grasses' reproductive phenology profoundly impacts plant morphogenesis, biomass production, and perenniality in natural ecosystems and cultivated grasslands. Complex interactions between vegetative and reproductive development complicate grass phenology prediction for various environments and genotypes. This work aims to analyse genetic × environment interactions effects on tiller growth and reproductive development in Lolium perenne. Three perennial ryegrass cultivars, Bronsyn, Carvalis, and Tryskal, were grown from seedling to heading under four inductive conditions. T0 plants were continuously exposed to high temperatures and long days (HT-LD). T1, T2, and T3, plants were initially exposed to low temperatures and short days (LT-SD) for 9 weeks. Then, T1 plants were immediately transferred to high temperatures and long days (HT-LD). Before their exposure to HT-LD, T2, and T3 plants were first transferred to high temperatures and short days (HT-SD) for 3 and 6 weeks, respectively. Leaf length, leaf emergence, and heading were regularly monitored. Floral transition and heading only occurred in T1, T2, and T3, i.e. after successive exposure to low temperature and long photoperiod. Bronsyn had higher heading earliness and proportion of reproductive tillers than Carvalis and Tryskal. The duration of HT-SD exposure affected the final number of leaves and spikelets. The rate of leaf and spikelet production significantly increased once plants were exposed to LD. Our results suggest an additive effect of the photoperiod and floral transition on leaf elongation rate. These findings enhance our understanding of the genetic × environment interactions on the vegetative and reproductive development in perennial ryegrass.

[This corrects the article DOI: 10.1093/aobpla/plae055.].

Water availability is one of the essential factors that determine the distribution of plant species, as well as their ecological strategies. The study of leaf phenology, in conjunction with other leaf traits of an ecological nature, such as functional traits, makes it possible to determine the life history strategies of plant species and their variation along environmental gradients, which in turn influences the demographic rates of populations. In the present study, we analysed the effect of water availability at the landscape scale on spring leaf phenology and foliar traits such as leaf mass per area (LMA) and leaf thickness (LT) in the oak species Quercus castanea from a tropical latitude in central-western Mexico. Six sites were selected in the Cuitzeo basin, Michoacán, across a water availability gradient, ranging from 766 mm to 1145 mm of mean annual precipitation. Leaf samples were collected from 10 adult trees at each site and LT and LMA were estimated. Leaf phenology was monitored for each tree every two weeks between March and July for two consecutive years, 2021 and 2022, alongside soil moisture measurements. Temperature and precipitation variables for the two study years were obtained from meteorological stations and long-term bioclimatic variables from the Worldclim database. Significant spatial and temporal variation in leaf phenology was observed. Earlier leaf development and shorter development times were observed with increased soil moisture in March and April, and with higher precipitation in October of the previous year. Also, sites with long-term higher precipitation seasonality and with lower precipitation of the warmest quarter showed longer development times. A positive association between development times and leaf thickness was also observed. Quercus castanea shows a brevideciduous leaf phenology but with significant variation among populations, reflecting spatiotemporal mosaics of environmental and genetic variation and in covariation with leaf functional traits such as leaf thickness.

Local adaptation is a common phenomenon that helps plant populations to adjust to broad-scale environmental heterogeneity. Given the strong effect of forest management on the understorey microenvironment and often long-term effects of forest management actions, it seems likely that understorey herbs may have locally adapted to the practiced management regime and induced environmental variation. We investigated the response of Anemone nemorosa and Milium effusum to forest management using a transplant experiment along a silvicultural management intensity gradient. Genets were sampled from sites with contrasting management intensities and transplanted sympatrically, near allopatrically and far allopatrically along the management intensity gradient to test for local adaptation and phenotypic plasticity, as well as to sites where the species were absent to test for recruitment versus dispersal limitations. We then measured survival and fitness traits over two growing seasons. We found only little evidence of local adaptation in A. nemorosa and M. effusum, whereas various traits in both species showed linear plastic changes in response to transplantation along the forest management intensity gradient. Furthermore, A. nemorosa performed worse when transplanted to unoccupied sites, suggesting recruitment limitation, whereas M. effusum performed better in unoccupied sites, suggesting dispersal limitation. Altogether, our results underpin the importance of forest management to indirectly drive phenotypic variation among populations of forest plants.

Changing climates are creating more intense and frequent high-temperature events that could disrupt forest communities. In temperate forests, we have a relatively limited understanding of how trees are impacted by heat events, hindering our ability to predict the impacts of future heat waves. We conducted a community-level assessment of thermal safety margins in 11 hardwood tree species native to eastern North America. We used chlorophyll fluorescence to determine the critical heat tolerance of photosystem II (PSII) across 2 years in central Tennessee, USA. We focus on the temperature at which PSII first starts to decline (T _crit) as this is the temperature where membranes become unstable, resulting in permanent damage to these tissues. T _crit varied within the season and between years, being higher in July than June and in 2022 than 2023. T _crit also varied among species with species like Ulmus rubra and Ostrya virginiana showing consistently lower heat tolerances. When compared to the record high temperature for our study site, 10 of 11 species would have experienced heat stress during at least one sample period. When compared to current year high temperatures, the risk was variable and lower across all species and sample periods. However, we found that leaf temperatures often exceeded air temperatures many species were likely heat stressed as heat tolerances were often below species-specific leaf temperatures. Indeed, four species were potentially heat stressed during every sample period. Our data highlights the importance of using leaf temperature, not air temperature to assess thermal safety margins and that community-wide stress may already occur under extreme heat conditions. As climate change intensifies, leaf temperatures will likely approach critical thresholds that lead to damage across the tree community. Understanding species-specific responses to heat stress is essential to predicting future forest dynamics and ecosystem functioning.

The success of plant species under climate change will be determined, in part, by their phenological responses to temperature. Despite the growing need to forecast such outcomes across entire species ranges, it remains unclear how phenological sensitivity to temperature might vary across individuals of the same species. In this study, we harnessed community science data to document intraspecific patterns in phenological temperature sensitivity across the multicontinental range of six herbaceous plant species. Using linear models, we correlated georeferenced temperature data with 23 220 plant phenological records from iNaturalist to generate spatially explicit estimates of phenological temperature sensitivity across the shared range of species. We additionally evaluated the geographic association between local historic climate conditions (i.e. mean annual temperature [MAT] and interannual variability in temperature) and the temperature sensitivity of plants. We found that plant temperature sensitivity varied substantially at both the interspecific and intraspecific levels, demonstrating that phenological responses to climate change have the potential to vary both within and among species. Additionally, we provide evidence for a strong geographic association between plant temperature sensitivity and local historic climate conditions. Plants were more sensitive to temperature in hotter climates (i.e. regions with high MAT), but only in regions with high interannual temperature variability. In regions with low interannual temperature variability, plants displayed universally weak sensitivity to temperature, regardless of baseline annual temperature. This evidence suggests that pheno-climatic forecasts may be improved by accounting for intraspecific variation in phenological temperature sensitivity. Broad climatic factors such as MAT and interannual temperature variability likely serve as useful predictors for estimating temperature sensitivity across species' ranges.

Systems-wide understanding of gene expression profile regulating flower colour formation in Rhododendron simsii Planchon is insufficient. In this research, integration analysis of ribonucleic acid (RNA)omics and microRNAome were performed to reveal the molecular mechanism of flower colour formation in three R. simsii varieties with red, pink and crimson flowers, respectively. Totally, 3129, 5755 and 5295 differentially expressed gene (DEG)s were identified through comparative transcriptome analysis between 'Red variety' and 'Pink variety' (1507 up-regulated and 1622 down-regulated), 'Red variety' and 'Crimson variety' (2148 up-regulated 3607 down-regulated), as well as 'Pink variety' and 'Crimson variety' (2089 up-regulated and 3206 down-regulated), which were involved in processes of 'catalytic activity', 'binding', 'metabolic process' and 'cellular process', as well as pathways of 'metabolic pathways', 'biosynthesis of secondary metabolites', 'plant-pathogen interaction' and 'phenylpropanoid biosynthesis'. A total of 215 miRNAs, containing 153 known miRNAs belonging to 57 families and 62 novel miRNA, were involved in flower colour formation. In particular, 55 miRNAs were significantly differently expressed. Based on miRNA-mRNA regulatory network, ath-miR5658 could affect the synthesis of pelargonidin, cyanidin and delphinidin through downregulating accumulation of anthocyanidin 3-O-glucosyltransferase; ath-miR868-3p could regulate isoflavonoid biosynthesis through downregulating expression of CYP81E1/E7; ath-miR156g regulated the expression of flavonoid 3',5'-hydroxylase; and ath-miR829-5p regulated flavonol synthasein flavonoid biosynthesis process. This research will provide important roles in breeding new varieties with rich flower colour.