We consider the functional separation of variables to the nonlinear diffusion equation with source and convection term： ut = （A（x）D（u）ux）x ＋ B（x）Q（u）, Ax ≠ 0. The functional separation of variables to thi...We consider the functional separation of variables to the nonlinear diffusion equation with source and convection term： ut = （A（x）D（u）ux）x ＋ B（x）Q（u）, Ax ≠ 0. The functional separation of variables to this equation is studied by using the group foliation method. A classification is carried out for the equations which admit the function separable solutions. As a consequence, some solutions to the resulting equations are obtained.展开更多
In order to reveal the genetic diversity and variation sources of leaf phenotypic traits in walnut,the coefficient of variation,Shannon-weaver index,phenotypic differentiation coefficient,and the correlation of 9 leaf...In order to reveal the genetic diversity and variation sources of leaf phenotypic traits in walnut,the coefficient of variation,Shannon-weaver index,phenotypic differentiation coefficient,and the correlation of 9 leaf phenotypic traits for 251 walnut germplasm resources from two walnut populations were analyzed.The results showed that the averages of the variation coefficients and Shannon-weaver indexes of the leaf phenotype traits were 17.45%and 1.86 respectively.The F values of most inter-population traits and all intra-population traits were highly significant,and the F values of inter-population leaf shape index,leaflet number,length and leaf length were very large.The averages of inter-population and intra-population differentiation coefficients were 9.15%and 90.85%respectively.The leaf size,leaf thickness,and leaflet number were highly correlated with trunk perimeters.According to the results of principal component analyses,the 9 traits can be simplified into four principal components,which represent leaf size,petiole,leaflet number and leaf shape,respectively.There were extensive variations and rich genetic diversities in leaf phenotypic traits of walnut,and the intra-population variation was the leading source of phenotypic trait variation.Leaf shape index,leaflet number,internode length and leaf length can be used for population classification.The size and thickness of leaves and the number of leaflets will affect the accumulation of nutrients in walnut tree,and then affect its trunk perimeter.展开更多
Plant leaf litter decomposition provides a source of energy and nutrients in forest ecosystems.In addition to traditional environmental factors,the degradation process of litter is also affected by plant functional tr...Plant leaf litter decomposition provides a source of energy and nutrients in forest ecosystems.In addition to traditional environmental factors,the degradation process of litter is also affected by plant functional traits and litter quality.However,at the community level,it is still unclear whether the relative importance of plant traits and litter quality on the litter decomposition rate is consistent.A year-long mixed leaf litter decomposition experiment in a similar environment was implemented by using the litterbag method in seven typical forest types in Dongling Mountain,Beijing,North China,including six monodominant communities dominated by Juglans mandshurica,Populus cathayana,Betula dahurica,Betula platyphylla,Pinus tabuliformis and Larix gmelinii var.principis-rupprechtii and one codominant community dominated by Fraxinus rhynchophylla,Quercus mongolica and Tilia mongolica.The results showed that there were considerable differences in the litter decomposition rate(k-rate)among the different forest types.The community weighted mean(CWM)traits of green leaves and litter quality explained 35.60%and 9.05%of the k-rate variations,respectively,and the interpretation rate of their interaction was 23.37%,indicating that the CWM traits and their interaction with litter quality are the main factors affecting the k-rate variations.In the recommended daily allowance,leaf nitrogen content,leaf dry matter content,leaf tannin content and specific leaf area were the main factors affecting the k-rate variations.Therefore,we suggest that future studies should focus on the effects of the CWM traits of green leaves on litter decomposition at the community level.展开更多
基金The project supported by National Natural Science Foundation of China under Grant No. 10371098 and the Program for New Century Excellent Talents in Universities under Grant No. NCET-04-0968
文摘We consider the functional separation of variables to the nonlinear diffusion equation with source and convection term： ut = （A（x）D（u）ux）x ＋ B（x）Q（u）, Ax ≠ 0. The functional separation of variables to this equation is studied by using the group foliation method. A classification is carried out for the equations which admit the function separable solutions. As a consequence, some solutions to the resulting equations are obtained.
文摘In order to reveal the genetic diversity and variation sources of leaf phenotypic traits in walnut,the coefficient of variation,Shannon-weaver index,phenotypic differentiation coefficient,and the correlation of 9 leaf phenotypic traits for 251 walnut germplasm resources from two walnut populations were analyzed.The results showed that the averages of the variation coefficients and Shannon-weaver indexes of the leaf phenotype traits were 17.45%and 1.86 respectively.The F values of most inter-population traits and all intra-population traits were highly significant,and the F values of inter-population leaf shape index,leaflet number,length and leaf length were very large.The averages of inter-population and intra-population differentiation coefficients were 9.15%and 90.85%respectively.The leaf size,leaf thickness,and leaflet number were highly correlated with trunk perimeters.According to the results of principal component analyses,the 9 traits can be simplified into four principal components,which represent leaf size,petiole,leaflet number and leaf shape,respectively.There were extensive variations and rich genetic diversities in leaf phenotypic traits of walnut,and the intra-population variation was the leading source of phenotypic trait variation.Leaf shape index,leaflet number,internode length and leaf length can be used for population classification.The size and thickness of leaves and the number of leaflets will affect the accumulation of nutrients in walnut tree,and then affect its trunk perimeter.
基金This work was supported by the National Natural Science Foundation of China(10300-210100218).
文摘Plant leaf litter decomposition provides a source of energy and nutrients in forest ecosystems.In addition to traditional environmental factors,the degradation process of litter is also affected by plant functional traits and litter quality.However,at the community level,it is still unclear whether the relative importance of plant traits and litter quality on the litter decomposition rate is consistent.A year-long mixed leaf litter decomposition experiment in a similar environment was implemented by using the litterbag method in seven typical forest types in Dongling Mountain,Beijing,North China,including six monodominant communities dominated by Juglans mandshurica,Populus cathayana,Betula dahurica,Betula platyphylla,Pinus tabuliformis and Larix gmelinii var.principis-rupprechtii and one codominant community dominated by Fraxinus rhynchophylla,Quercus mongolica and Tilia mongolica.The results showed that there were considerable differences in the litter decomposition rate(k-rate)among the different forest types.The community weighted mean(CWM)traits of green leaves and litter quality explained 35.60%and 9.05%of the k-rate variations,respectively,and the interpretation rate of their interaction was 23.37%,indicating that the CWM traits and their interaction with litter quality are the main factors affecting the k-rate variations.In the recommended daily allowance,leaf nitrogen content,leaf dry matter content,leaf tannin content and specific leaf area were the main factors affecting the k-rate variations.Therefore,we suggest that future studies should focus on the effects of the CWM traits of green leaves on litter decomposition at the community level.
