浙江天童植物叶片氮磷含量的群落内变异

探索植物叶片氮(N)、磷(P)的种间、种内变异及其群落学特征,对于揭示群落构建机制具有重要意义.本研究在浙江天童地区常绿阔叶林内,选择一个40m×40m的样地,逐一测定了46种植物共554株个体叶片的N和P含量,从群落物种组成与内部环境特征方面分析了植物叶片的N和P化学计量关系.结果表明:①植物叶片N含量的平均值为(16.7±5.11)mg.g-1,P含量的平均值为(0.44±0.25)mg.g-1,N/P平均值为44.99±23.53;②利用个体多度较高物种的加权平均值可以较好地反映群落水平叶片的N和P化学计量特征;③叶片N含量的变异主要发生在物种之间,而叶片P含量的变异主要发生在种内;④群落内叶片N、P含量随光照程度增强而上升.可以认为:叶片N、P含量变异都受到遗传与环境因素的双重影响,在P限制条件下,叶片P含量变异受到环境因素影响更为强烈.

Within-community variability of plant leaf N and P contents in Tiantong, Zhejiang Province

Exploring inter- and intra-specific variations in leaf N and P contents and their relationship with other community properties is important for revealing community assembly. In this study a plot with size of 40 m×40 m, containing 46 species and 554 individuals, was selected in an evergreen broad-leaved forest (EBLF) in Tiantong region, Zhejiang Province. The N and P contents in foliage of each individual were quantified. The inter- and intra-specific variations in leaf N and P stoichiometry and their relationship with each of community height, individual size and micro-environmental conditions were analyzed. It was found that ① the mean of N and P contents and N/P was (16.7±5.11) mg·g ^-1, (0.44±0.25) mg·g ^-1, and (44.99±23.53) mg·g ^-1, respectively; ② leaf N and P stoichiometry at community level can be accurately estimated by the weighted mean value resulting from the most abundant species; ③ inter-species scale was responsible for the relatively large variance of leaf N contents, while intra-species scale was accounted for the relatively large variation in P content; and ④ leaf N and P increased with increasing plant light exposure. It was concluded that variation in N and P contents is determined by both inter- and intra species differences, but P content is mainly controlled by community environment under P limited conditions.