Community structure and species diversity dynamics of a subtropical evergreen broad-leaved forest in China:2005 to 2020

Here,we characterize the temporal and spatial dynamics of forest community structure and species diversity in a subtropical evergreen broad-leaved forest in China.We found that community structure in this forest changed over a 15-year period.Specifically,renewal and death of common species was large,with the renewal of individuals mainly concentrated within a few populations,especially those of Aidia canthioides and Cryptocarya concinna.The numbers of individual deaths for common species were concentrated in the small and mid-diameter level.The spatial distribution of community species diversity fluctuated in each monitoring period,showing a more dispersed diversity after the 15-year study period,and the coefficient of variation on quadrats increased.In 2010,the death and renewal of the community and the spatial variation of species diversity were different compared to other survey years.Extreme weather may have affected species regeneration and community stability in our subtropical monsoon evergreen broad-leaved forests.Our findings suggest that strengthening the monitoring and management of the forest community will help better understand the long-and short-term causes of dynamic fluctuations of community structure and species diversity,and reveal the factors that drive changes in community structure.

Breeding new cultivars for sustainable wheat production

Common wheat(Triticum aestivumL.)is amajor staple food crop that feeds about 40% of the world’s population.Wheat production and utilization accounts for^28% of the global cereal crops(http://www.foodsecurityportal.org/)food-outlookbiannual-report-global-food-markets.Consequently,wheat supplies approximately one-fifth of human calories in a variety of forms,including leavened,flat and steamed breads,biscuits,cakes,different forms of noodles,pasta,couscous,and pies,as well as secondary products such as starch,gluten and nonflour milling fractions.Wheat consumption has been steadily increasing due to population expansion and urbanization.For example,wheat consumed in China increased more than sixfold(from 19 million tons to 123 million tons)in the 50 years from 1962 to 2012[1].

Nutritional geometry framework of sucrose taste in Drosophila

Dietary protein(P)and carbohydrate(C)have a major impact on the sweet taste sensation.However,it remains unclear whether the balance of P and C influences the sweet taste sensitivity.Here,we use the nutritional geometry framework(NGF)to address the interaction of protein and carbohydrates on sweet taste using Drosophila as a model.Our results reveal that high-protein,low-carbohydrate(HPLC)diets sensitize to sweet taste and low-protein,high-carbohydrate(LPHC)diets desensitize sweet taste in both male and female flies.We further investigate the underlying mechanisms of the effects of two diets on sweet taste using RNA sequencing.When compared to the LPHC diet,the m RNA expression of genes involved in the metabolism of glycine,serine,and threonine is significantly upregulated in the HPLC diet group,suggesting these amino acids may mediate sweet taste perception.We further find that sweet sensitization occurs in flies fed with the LPHC diet supplemented with serine and threonine.Our study demonstrates that sucrose taste sensitivity is affected by the balance of dietary protein and carbohydrates possibly through changes in serine and threonine.

Distribution patterns of tree species in an evergreen broadleaved forest in eastern China

Ecological assembly rules in evergreen broad-leaved forest are far from clear understanding.Spatial dispersion of individuals in a species is central in ecological theory.We analyzed the spatial patterns as well as associations between adult and juvenile of each tree species in a 5-ha subtropical evergreen broad-leaved forest plot in eastern China.Out of the 74 species occurring with more than 10 individuals,88.4%of these species are aggregated.Most of them are aggregated from small to large scales.Spatial distributions of some species corre-spond with topography.Many bad dispersed species in the Baishanzu exhibit a highly aggregated distribution at small scales.These suggest that environmental heterogeneity and/or dispersal limitation may be the most important mechanisms that control the distribution patterns of these species.Our observations of the aggregations of abundant species basically support the hypothesis that dispersal limitation decreases as the number of reproductive trees increases.The rest species are randomly distributed,with less than 10 individuals.For most common species,spatial aggregation is weaker in larger diameter classes,and the distance between adults is larger than that between juveniles and adults,suggesting that density-dependence works on loosing aggregation and excluding conspecific juveniles away from adult trees.However,the density-dependent effect is not strong enough to eliminate all seedlings near adult trees and to result in a regular distribution of trees;thus the density dependence is usually masked by the refuge effect.