贵阳市常绿树种叶子寿命的研究

Leaf longevity of main evergreen tree species of Guiyang City

贵阳市的典型植被为喀斯特植被,其中喀斯特常绿针叶林、喀斯特常绿阔叶林及喀斯特常绿灌丛在当地的生态系统中有着重要生态作用。在不同的生活型植物中,通过以优势种以及主要伴生种为研究对象、利用生命表法计算叶子的平均期望寿命(EX)来对贵阳市喀斯特植被主要常绿树种叶子寿命进行调查研究。结果表明:①大多数常绿树种叶子的寿命在0～2年之间,并且变化幅度较大,各个树种叶片寿命的更新周期不同。②不同生活型植物叶片寿命存在差异,小乔木及灌木的叶子寿命较长,中乔木叶子的寿命较短,但是这个差异并不显著。③不同植被型组植物叶片寿命不相同,而且差异较为显著。鉴于贵阳市喀斯特植被的特殊性,讨论叶子寿命的影响因素,并且与已有研究比较分析得出贵阳市常绿树种叶片寿命有自己的分布格局。

The typical vegetation coverage in Guiyang is Karst vegetation,among which Karst evergreen conifer forest,Karst evergreen broadleaf forest and Karst evergreen shrubs are of great significance on the local ecological system.This research investigated the leaf longevity of main evergreen tree species of Guiyang Karst vegetation by taking the dominant species and companion species as the main objects in varied life-form species and computing the average life expectancy（Ex） based on life-table method.The results are as follows： ① The leaf lifespan of evergreen tree species mostly ranged from 0 to 2 years,with large variation and different replacing periods of every tree species.② Difference in leaf lifespan of varied life-form species exsited.Average leaf lifespan was relatively longer in small trees and shrubs than in large trees,but was not significantly different.③The species leaf lifespan was obviously different in varied forms of vegetation.Reckoning with the speciality of vegetation in Guiyang,the present study discussed the influencing factors of leaf lifespan and concluded that the leaf lifespan had its own specific scatter pattern in Guiyang.