桂花植冠的枝系构型分析

Architectural Analysis of Osmanthus fragrans Crown Geometry

采用Strahler法对福建省石峰寨风景区内的不同生长发育阶段桂花(Osmanthus fragrans)的枝系构型进行了统计分析。结果表明:桂花的分枝格局参数,除总体分枝率和逐步分枝率SBR1:2无显著变化外,其余参数因发育阶段的不同,均发生不同程度的变化。枝系构型的比较分析表明:成树阶段高生长不明显,以拓展上层空间为主,幼苗阶段表现出高生长,幼树阶段则表现出从高生长向横向生长过渡的趋势。通过分析叶片配置发现:在不同枝系上,叶片均集中于植冠内一级枝和二级枝上;叶片的大小从幼苗、幼树到成树阶段逐渐增大。这些说明桂花在不同生长发育阶段,枝系构型表现出一定的可塑性,反映了不同的适应对策。

Branching pattern was studied in Osmanthus fragrans grown in Shifengzai Scenery, Fujian Province, China, by the Strahler method. The architectural parameters （overall bifurcation ratio, stepwise bifurcation ratio （SBR1：2 and SBR2：3）, length of the first-order branch, ratio of branch diameter （RBD2：1）, branch angle and leaf angle） varied with the different growth and development stages. The architectural comparison of branches showed that height growth was obvious at the seedling stage, transition from height growth to crown expansion occurred at the sapling stage, and the crown diameter increased rapidly with slow height growth at the mature stage. The analysis of leaf distribution showed that the leaves are distributed mainly at the first-order branches and the third-order branches, and the leaf size increased with the growth and development of O. fragrans. It is suggested that the plasticity of branching pattern is an adaptive strategy of O. fragrans.