Tree-ring width chronologies of Larix chinensis were developed from the northern and southern slopes of the Qinling Mountains in Shaanxi Province,and climatic factors affecting the tree-ring widths of L.chinensis were...Tree-ring width chronologies of Larix chinensis were developed from the northern and southern slopes of the Qinling Mountains in Shaanxi Province,and climatic factors affecting the tree-ring widths of L.chinensis were examined.Correlation analysis showed that similar correlations between tree-ring width chronologies and climatic factors demonstrated that radial growth responded to climate change on both slopes.The radial growth of L.chinensis was mainly limited by temperature,especially the growing season.In contrast,both chronologies were negatively correlated with precipitation in May of the previous year and April of the current year.Spatial climate-correlation analyses with gridded land-surface climate data revealed that our tree-ring width chronologies contained a strong regional temperature signal over much of northcentral and eastern China.Spatial correlation with seasurface temperature fields highlights the influence of the Pacific Ocean,Indian Ocean,and North Atlantic Ocean.Wavelet coherence analysis indicated the existence of some decadal and interannual cycles in the two tree-ring width chronologies.This may suggest the influences of El Nin˜o-Southern Oscillation and solar activity on tree growth in the Qinling Mountains.These findings will help us understand the growth response of L.chinensis to climate change in the Qinling region,and they provide critical information for future climate reconstructions based on this species in semi-humid regions.展开更多
The effect of genotypic diversity on the age structure and bud bank of the Leymus chinensis population has not yet been demonstrated.This experiment was designed to study the age structure of the tiller,rhizome,and bu...The effect of genotypic diversity on the age structure and bud bank of the Leymus chinensis population has not yet been demonstrated.This experiment was designed to study the age structure of the tiller,rhizome,and bud of L.chinensis at genotypic diversity levels of 1,2,4,8,and 12.A total of 64 communities were established in this experiment,following the principle of randomized block experimental design.The results indicated that genotypic diversity had a significant or obviously significant effect on the cumulative length of rhizomes of 2a and 4a,dry matter accumulation of rhizomes of 1a and 2a,tiller number of 1a,tiller productivity of 3a,but had no significant effect age structure of buds.As the levels of genotypic diversity increased,the proportion of the cumulative length of rhizomes with 4a decreased and then increased,and dry matter accumulation of rhizomes with 1a and 2a gradually increased while the number of tillers with 1a gradually decreased,when the gradient of genotypic diversity increased.At the 1,2,4,8,and 12 genotype diversity levels,the number of tillers,the cumulative length of rhizomes,and dry matter accumulation in rhizomes and buds were all age structures of expanding type.However,tiller productivity was an expanding or stable age structure at levels of 1,2,4,8 genotypic diversity,while it was a declining age structure at the 12 genotype diversity gradient.An appropriate genotypic diversity is conducive to maintaining the growth and stability of the age structure of L.chinensis population,but too high a gradient of genotypic diversity can have a negative impact on the population age structure.This study provided that an appropriate number of genotypic diversity contributes to the stability of the population.展开更多
Many studies have shown that climatic and edaphic factors influence the variations in nitrogen isotopes(δ^(15)N)in terrestrial ecosystems.However,the relative importance of co-varying climatic and edaphic controls on...Many studies have shown that climatic and edaphic factors influence the variations in nitrogen isotopes(δ^(15)N)in terrestrial ecosystems.However,the relative importance of co-varying climatic and edaphic controls on plantδ^(15)N remains somewhat unclear.To address this issue,regional-scale plant(L.chinensis)and soil samples were collected along a longitudinal transect across the temperate grasslands in northern China.The influences of climatic and edaphic factors on the plantδ^(15)N were disentangled using the variable importance in projection(VIP)approach.We found that the climatic and edaphic variables explained 52.4%and 31.2%,respectively,of the variation in plantδ^(15)N.The mean annual precipitation(MAP),soil N,and mean annual temperature(MAT)were the most important variables,but the soil water content(SWC),aridity index(AI),and soil clay content were also important variables.The soil pH and soil C:N ratios were identified as unimportant variables.Furthermore,a high-performance model for simulating plantδ^(15)N values was constructed based on the important variables(VIP>0.8).Further investigations should focus on the effects of the interaction between the climatic and edaphic variables on the N cycles in the temperate grasslands to provide more reliable predictions of plantδ^(15)N.展开更多
基金funded by National Natural Science Foundation of China(No.31370587)
文摘Tree-ring width chronologies of Larix chinensis were developed from the northern and southern slopes of the Qinling Mountains in Shaanxi Province,and climatic factors affecting the tree-ring widths of L.chinensis were examined.Correlation analysis showed that similar correlations between tree-ring width chronologies and climatic factors demonstrated that radial growth responded to climate change on both slopes.The radial growth of L.chinensis was mainly limited by temperature,especially the growing season.In contrast,both chronologies were negatively correlated with precipitation in May of the previous year and April of the current year.Spatial climate-correlation analyses with gridded land-surface climate data revealed that our tree-ring width chronologies contained a strong regional temperature signal over much of northcentral and eastern China.Spatial correlation with seasurface temperature fields highlights the influence of the Pacific Ocean,Indian Ocean,and North Atlantic Ocean.Wavelet coherence analysis indicated the existence of some decadal and interannual cycles in the two tree-ring width chronologies.This may suggest the influences of El Nin˜o-Southern Oscillation and solar activity on tree growth in the Qinling Mountains.These findings will help us understand the growth response of L.chinensis to climate change in the Qinling region,and they provide critical information for future climate reconstructions based on this species in semi-humid regions.
基金supported by the National Natural Science Foundation of China(32071860).
文摘The effect of genotypic diversity on the age structure and bud bank of the Leymus chinensis population has not yet been demonstrated.This experiment was designed to study the age structure of the tiller,rhizome,and bud of L.chinensis at genotypic diversity levels of 1,2,4,8,and 12.A total of 64 communities were established in this experiment,following the principle of randomized block experimental design.The results indicated that genotypic diversity had a significant or obviously significant effect on the cumulative length of rhizomes of 2a and 4a,dry matter accumulation of rhizomes of 1a and 2a,tiller number of 1a,tiller productivity of 3a,but had no significant effect age structure of buds.As the levels of genotypic diversity increased,the proportion of the cumulative length of rhizomes with 4a decreased and then increased,and dry matter accumulation of rhizomes with 1a and 2a gradually increased while the number of tillers with 1a gradually decreased,when the gradient of genotypic diversity increased.At the 1,2,4,8,and 12 genotype diversity levels,the number of tillers,the cumulative length of rhizomes,and dry matter accumulation in rhizomes and buds were all age structures of expanding type.However,tiller productivity was an expanding or stable age structure at levels of 1,2,4,8 genotypic diversity,while it was a declining age structure at the 12 genotype diversity gradient.An appropriate genotypic diversity is conducive to maintaining the growth and stability of the age structure of L.chinensis population,but too high a gradient of genotypic diversity can have a negative impact on the population age structure.This study provided that an appropriate number of genotypic diversity contributes to the stability of the population.
基金This research was financed by the Natural Science Foundation of Hunan Province(No.2020JJ4296).
文摘Many studies have shown that climatic and edaphic factors influence the variations in nitrogen isotopes(δ^(15)N)in terrestrial ecosystems.However,the relative importance of co-varying climatic and edaphic controls on plantδ^(15)N remains somewhat unclear.To address this issue,regional-scale plant(L.chinensis)and soil samples were collected along a longitudinal transect across the temperate grasslands in northern China.The influences of climatic and edaphic factors on the plantδ^(15)N were disentangled using the variable importance in projection(VIP)approach.We found that the climatic and edaphic variables explained 52.4%and 31.2%,respectively,of the variation in plantδ^(15)N.The mean annual precipitation(MAP),soil N,and mean annual temperature(MAT)were the most important variables,but the soil water content(SWC),aridity index(AI),and soil clay content were also important variables.The soil pH and soil C:N ratios were identified as unimportant variables.Furthermore,a high-performance model for simulating plantδ^(15)N values was constructed based on the important variables(VIP>0.8).Further investigations should focus on the effects of the interaction between the climatic and edaphic variables on the N cycles in the temperate grasslands to provide more reliable predictions of plantδ^(15)N.
