云南普洱季风常绿阔叶林优势物种不同生长阶段叶片碳、氮、磷化学计量特征

Leaf carbon,nitrogen and phosphorus stoichiometry at different growth stages in dominant tree species of a monsoon broad-leaved evergreen forest in Pu'er,Yunnan Province,China

为探索植物叶片氮(N)、磷(P)、碳(C)生态化学计量特征随植物生长发育的变化规律,在普洱季风常绿阔叶林中,选取6种优势植物种(红锥(Castanopsis hystrix)、短刺锥(Castanopsis echidnocarpa)、泥柯(Lithocarpus fenestratus)、截果柯(Lithocarpus truncatus)、西南木荷(Schima wallichii)、茶梨(Anneslea fragrans))采集叶片,分析其N、P、C含量及化学计量比随植物生长发育的变化。结果显示:6种植物在不同生长阶段的N含量变化范围为7.90–17.72 mg·g–1,P为0.34–1.39 mg·g–1,C为458.48–516.87 mg·g–1,C:N为28.04–65.70,N:P为11.41–63.50,C:P为355.23–1 878.17,且不同生长阶段6种植物及总体叶片N、P、C含量及其化学计量比变化趋势各异。在变异系数上,N:P比整体变异最大,为36.46%(变化范围19.19%–91.65%),其次为C:P,为34.80%(变化范围15.99%–91.60%),C的整体变异最小,为3.12%(变化范围1.61%–5.89%)。变异来源分析结果显示,N含量、C含量、C:N、N:P及C:P均主要受植物生长阶段的影响,而P含量主要受物种与生长阶段的交互作用影响。

Aims Our objective was to explore the effect of growth stage on leaf C：N：P stoichiometry in dominant species of a monsoon broad-leaved evergreen forest in Pu＇er,Yunnan Province.Methods We collected leaves from six dominant species（i.e. Castanopsis hystrix,C. echidnocarpa,Lithocarpus fenestratus,L. truncatus,Schima wallichii and Anneslea fragrans） at different growth stages from seedlings to mature trees. The leaf N,P and C contents were measured. The effects of species,growth stage and their interaction on leaf C,N and P contents and stoichiometry were analyzed by Repeated-Measure ANOVA in SPSS 19.0. Important findings The ranges of leaf N,P and C contents and mass ratios of C：N,N：P and C：P in the six species across different growth stages were 7.90–17.72 mg·g^–1,0.34–1.39 mg·g^–1,458.48–516.87 mg·g^–1,28.04– 65.70,11.41–63.50 and 355.23–1 878.17,respectively. The coefficient of variation（CV） for N：P mass ratio ranged between 19.19%–91.65%,with an average of 36.46%; CV for C：P varied between 15.99%–91.60%,with an average of 34.80%; whilst CV for C varied between 1.61%–5.89%,with an average of 3.12%. Factorial analysis of the variation for each variable,with growth stage and species as independent factors,showed that leaf N and C contents and the mass ratios of leaf C：N,N：P and C：P were mainly determined by growth stage,while leaf P content was mainly determined by an interaction between growth stage and species.