神木天坑不同小生境木本植物叶功能性状的差异与关联

Differences and correlations in leaf functional traits of woody plants in different microhabitats of Shenmu Tiankeng

关键词:  叶功能性状, 木本植物, 天坑, 性状差异, 相关性

Key words:  leaf functional traits, woody plants, tiankeng, trait difference, correlation

摘要:

为进一步探讨天坑生境下木本植物的生存策略,该研究以神木天坑不同小生境(底部、坑腰和边缘)的木本植物为对象,选取叶厚度、叶组织密度、叶面积等10个叶功能性状指标,运用单因素方差分析和相关性分析等方法,分析了天坑木本植物叶功能性状的变异特征以及小生境对木本植物叶功能性状的影响。结果表明:(1)在神木天坑木本植物10个叶功能性状中,叶面积变异系数最大(113.9%),叶碳含量变异系数最小(10.5%)。(2)天坑边缘、坑腰的乔木叶组织密度显著高于底部(P<0.05),天坑底部乔木、灌木的叶钾含量显著高于边缘(P<0.05),3种小生境中木质藤本未出现显著差异(P>0.05)。(3)不同小生境叶功能性状相关性存在一定差异,从天坑底部到边缘小生境,叶厚度与叶面积逐渐呈极显著正相关; 主成分分析结果显示叶组织密度(-0.833)、叶钾含量(0.782)、叶干物质含量(-0.647)贡献较大,是神木天坑不同小生境木本植物叶功能性状的主要指标。综上认为,叶功能性状之间普遍关联,天坑木本植物通过对叶功能性状的权衡来适应不同小生境。该研究结果为了解植物对特殊生境的适应机制以及天坑植被的保护提供了理论指导。

Abstract:

In order to further explore the survival strategy of woody plants in tiankeng habitat. This study selected woody plants in different microhabitats(bottom, waist and edge of Shenmu Tiankeng)as the objects. Shenmu Tiankeng is a typical karst tiankeng in Dashiwei Tiankeng Group in Guangxi, and there is a well-preserved underground forest that is easily accessible. Ten leaf functional traits(leaf thickness, leaf tissue density, leaf area, etc.)were selected, and single-factor analysis of variance and correlation analysis were conducted to investigate the relationship between leaf functional traits in different microhabitats. The results were as follows:(1)Among the 10 leaf functional traits of woody plants in Shenmu Tiankeng, the variable coefficient for leaf area(113.9%)was highest, while leaf carbon content was relatively stable(10.5%).(2)Ten leaf functional traits were almost no significant differences(P>0.05)for woody lianas in three different microhabitats. The leaf tissue density for trees was significantly higher at the edge and waist compared to the bottom(P<0.05), while the leaf potassium contents for trees and shrubs at the bottom were higher than that at the edge(P<0.05).(3)There were some differences in the correlation of leaf functional traits in different microhabitats. Leaf thickness was extremely significantly positively correlated with leaf area(P<0.01)at the edge of Tiankeng. The results of principal component analysis suggested that leaf tissue density(-0.833), leaf potassium content(0.782), and leaf dry matter content(-0.647)were the critical indicators for leaf functional traits of woody plants in different microhabitats of Shenmu Tiankeng. In conclusion, there is a general correlation between leaf functional traits, and this study demonstrate that different growth types of woody plants can adapt to the three microhabitats of tiankeng via the trade-off of leaf functional traits. This study is expected to provide theoretical guidance for understanding the adaptation mechanism of plants to special habitats and the protection of tiankeng vegetation.