Microsatellite genotypic data of Euptelea pleiospermum in STRUCTURE format

We sampled leaves from 678 individuals in 21 natural populations (30-36 individuals per population), covering the entire distribution of Euptelea pleiospermum in China.Total DNA was isolated from about 50 mg powdered leaf tissue following the protocol of a DNA extraction kit (Tiangen Biotech Co., LTD., Beijing, China). We used seven fluorescence-labeled microsatellite loci (EP036, EP059, EP081, EP087, EP091, EP278 and EP294; Zhang et al., 2008) to genotype our 678 DNA samples

Contrasting elevational patterns of genetic variation in Euptelea pleiospermum along mountains at the core and edges of its latitudinal range

Patterns of genetic variation along both latitudinal and elevational gradients have been intensively studied in the last few decades. To date, however, elevational patterns of genetic diversity and gene flow remain rarely compared for the same species along mountains at the center and edges of its latitudinal range. We used nuclear microsatellite analysis to compare the elevational patterns of both genetic variation and gene flow for Euptelea pleiospermum along elevational transects on the Qinling (33 degrees N; leading edge), Shennongjia (31 degrees N; mid-latitude), and Emei (29 degrees N; rear edge) Mountains in China. First, we found no elevational pattern of genetic diversity along the two marginal mountains, but we found higher genetic diversity in the middle-altitude populations than in the low- and high-altitudes along the mid-latitude mountain. Second, there was no obvious genetic structure along the two marginal mountains, but individuals along the mid-latitude mountain were clustered into the upper and lower groups. Third, the contemporary gene flow along the two marginal mountains was higher than that along the mid-latitude mountain. Lastly, we found no isolation-by-distance along all three mountains and a significant isolation-by-elevation along the mid-latitude mountain but not along the two marginal mountains. Our results demonstrated that the elevational patterns of both genetic variation and gene flow for a tree species are different along mountains at the core and edges of its latitudinal range. These differences are likely associated with the discrepancies in spatial isolation, ecological stability, and vegetation types, but not historical events (e.g., post-glacial recolonization) at different latitudes

Seed morphological traits and seed element concentrations of an endangered tree species displayed contrasting responses to waterlogging induced by extreme precipitation

Understanding how plant species respond to extreme climate events is crucial for planning management and conservation actions. As extreme precipitation accelerates, the waterlogging related to it is predicted to be more severe and frequent. To date, however, empirical studies addressing the effects of extreme precipitation-induced waterlogging on the seeds of wild plants are still scarce. In this study, we compared the size, mass and element concentration of seeds produced by non-inundated and inundated individuals of Sinojackia huangmeiensis, a critically endangered tree species with only one extant wild population. Compared to the seeds from non-inundated individuals, the seed length, seed width, and seed mass were all smaller for seeds from inundated individuals. However, the concentrations of four chemical elements in the seed displayed an opposite trend, except those elements (e.g., C, K, Ca, Mg, Al, Fe, Ni, B, Mo, and Cu) with no significant difference. Some toxic elements (e.g., Mn) accumulated in the seeds from inundated individuals, as well as some nucleic acid-protein elements (e.g., N and P) and enzymatic (e.g., Zn) elements. Our study provides rare empirical evidence that wild plants could respond to extreme precipitation-induced waterlogging by changing both seed morphological traits and element concentrations

Adaptive strategies and driving factors of a montane riparian tree: Trait-specific mechanisms across latitude

Investigating the drivers of phenotypic and genetic divergence can reveal the underlying processes and strategies that species adopt in rapidly changing environments. However, knowledge of adaptive strategies and the underlying mechanisms is lacking for the majority of taxa, especially those living in habitats sensitive to climate change. Here, we investigated 20 populations of a Tertiary-relict tree species, Eaptelea pleiospermum (Eupteleaceae), scattered in a mountain riparian habitat in China. We integrated genetic, growth, and reproductive traits, and evaluated the relative contributions of climatic and soil factors on genetic and functional trait divergence. The E pleiospermurn populations were divided into south and north genetic clusters, and there were significant differences in leaf density and seed mass of adult trees between the two. The spatial pattern of genetic divergence resulted from effects of both isolation by distance (IBD) and isolation by environment (IBE), whereas the divergence of growth and reproductive traits resulted solely from IBE effects. Spatial distance and selection by temperalure and soils played dominant roles in genetic divergence. Precipitation drove he spatial divergence of sprouling. Both divergence of leaf density and seed mass were prominently induced by genetic divergence, and the influences might be enhanced by LemperaLure and soil nutrienis. We infer that E. pleiuspennum populations adopt a resource-conservalive strategy with low growth rates and higher sprouLing under flooding disturbance, with larger seeds for improved seedling recruitmenl. at lower lathucles. In contrast, high growth rare and sexual reproduction with small seeds are strategies adopted by populations al higher lathucles. We conclude Lhal sprouting ref-leas a plaslic response Lo precipiLiLion, and leaf densiLy and seed mass reflect local adaplion under selection by temperature and soil factors.The underlying mechanisms of species adaptation strategies were traitspecific. Temperature and soil conditions are likely the main ecological factors shaping plant divergence in montane riparian regions. (C) 2020 Elsevier BM. All rights reserved

Pattern and drivers of species-genetic diversity correlation in natural forest tree communities across a biodiversity hotspot

Aims Exploring species-genetic diversity correlation (SGDC) is essential for understanding spatial patterns of diversity and the underlying mechanisms. Until now, latitudinal patterns of species diversity (SD) and genetic diversity (GD) were rarely studied simultaneously. As the freezing-tolerance hypothesis predicts a decrease of SD from low to high latitudes and the central-marginal hypothesis predicts a unimodal pattern of GD along latitude, we hypothesized that SD and GD are uncorrelated. We also tested how climatic and edaphic factors affect the correlation between the two levels of biodiversity. Methods We measured (i) SD (species richness and Simpson's diversity index) and community dissimilarity of woody plants (63 plots), (ii) GD (allelic richness and expected heterozygosity) and genetic differentiation of a dominant tree species (Euptelea pleiospermum; 678 individuals from 21 populations) using nuclear microsatellite data, and (iii) climatic (annual mean precipitation, annual mean temperature, minimum temperature, maximum temperature, annual relative moisture, solar radiation, photosynthetically active radiation) and edaphic (total C, total N, total P, available P, K, Ca, Mg, Al, Fe, Mn, Ni, Zn, B, Mo, Cu, pH) variables of 21 sites. We conducted both linear and quadratic regression analyses of diversity parameters against latitude. Relationships between SD and GD were tested using Pearson's correlation. Pearson's and Spearman's. correlation coefficients were calculated between diversity parameters and environmental variables. We used stepwise multiple regression analysis to identify the significant environmental predictors of SD and GD. Important Findings We observed no significant correlation between measures of SD and GD. SD decreases with increasing latitude, which can be partly explained by the freezing-tolerance hypothesis, whereas GD presents a unimodal pattern along the latitudinal gradient, which is consistent with the prediction of the central-marginal hypothesis. The contrasting latitudinal patterns of SD and GD indicate that the two levels of biodiversity do not co-vary in space. Based on both correlation analysis and stepwise multiple regression analysis, SD is only related to climatic variables, whereas GD is mainly related to edaphic variables. Our results show that different geographical and environmental factors affect SD and GD, driving the non-significant correlation between the two fundamental levels of biodiversity. Furthermore, a significantly positive correlation was observed between genetic distance and community dissimilarity, both of which were significantly correlated with geographical distance