太行山低山丘陵区火炬树克隆分株的生长策略

Growth strategy of Rhus typhina clonal ramets in the hilly area of the Taihang Mountains

探讨了太行山低山丘陵区次生疏灌草丛火炬树Rhus typhina克隆分株的生长策略。基于邻接小样方调查方法,对农田和疏灌草丛2种生境上火炬树克隆分株异速生长特点进行了研究。研究结果表明:①火炬树分株克隆生长独特,幼期冠幅生长超过树高生长、分株水平侧根前端直径约为后端直径2倍;②火炬树克隆分株冠幅与树高呈现幂函数异速生长规律,而对于前后端水平侧根直径,则以农田的稳定性显著高于疏灌草丛;③火炬树克隆分株数量以农田生境远高于疏灌草丛,前者的火炬树克隆分株密度约为后者的31倍。所以,火炬树克隆分株的生长策略是以枝叶侧向生长快于树高生长,促使火炬树克隆分株快速占据疏灌草丛上层,利于火炬树单优群落的形成并不断向外缘扩散。

To understand the growth strategies of clonal ramets from Rhus typhina, an exotic tree species, in the shrub-grassland of the hilly area of the Taihang Mountains in north China, a relevant analysis was conducted on the heterogeneous growth characteristics of R. typhina clonal ramets in two different habitats, farmland and shrub-grassland, using a continuous quadrat method. The major results for clonal ramets of R. typhina were as follows： 1 ） the front part of the lateral root diameter was two times larger than the back, and growth rates of crown width were faster than the height; 2） there was a power function relationship for crown width and tree height, with the heterogeneous growth of the front and back parts of the lateral root diameter more stable on farmland than in the shrub-grassland ; and 3 ） ranlets on farmland were 31 times greater than in the shrub-grassland ecotype. A growth strategy with much faster lateral branch and leaf growth than tree height, enabled clonal ramets of R. t）phina to form a dominant synusium resulting in gradual disappearance of the native deciduous shrub and grass synusiums. [ Ch, 5 fig. 3 tab. 22 ref. ]