木棉树形结构和叶性状对生境要素的响应研究

Tree shape structure and leaf trait responses to habitat elements of Bombax ceiba

关键词:  木棉, 生境要素, 树形结构, 叶性状, 冗余分析, 结构方程模型

Key words:  Bombax ceiba, habitat elements, tree shape structure, leaf trait, redundancy analysis, structural equation model

摘要:

植物形态结构是植物本身与外部环境共同作用的结果。为了分析木棉树形结构与叶性状的相关关系,探索地形、土壤和气象要素对木棉生长的影响,以及揭示木棉的生长策略和适应机制,该文以云南省西双版纳国家级自然保护区内230棵木棉为研究对象,测定6个树形结构指标,8个叶性状指标以及所在区域地形、气象、土壤养分等生境要素,使用结构方程模型和变差分解分析各生境要素对木棉树形结构和叶性状的影响和解释度。结果表明:(1)木棉树形结构各观测指标之间、叶性状各观测指标之间存在相关性(P<0.05)。(2)生境要素各观测指标对木棉生长具有较强影响,其中年均降雨量、坡度、平均温度对木棉生长指标的解释率较高,是影响木棉生长的主要生境指标。(3)从标准化路径系数看,3个生境要素对木棉树形结构和叶性状影响具有一致性,均表现为地形要素>气象要素>土壤要素。(4)3个生境要素叠加解释了树形结构和叶性状分别为43.5%和12.3%,表现出树形结构对生境环境的响应大于叶性状对环境响应的特点。研究结果初步探明了木棉不同生长指标对环境要素的适应策略,为木棉在异质生境的培育、繁殖以及木棉人工林高效经营等提供了理论依据和实践参考。

Abstract:

Morphology and structure of plants are the results from the joint action of itself and the external environment. In order to analyze the correlation between tree shape structure and leaf trait of Bombax ceiba, and to explore the influence of topographic, soil, and meteorological elements on its growth shape, and to reveal its growth strategy and adaptation mechanism, we studied 230 B. ceiba trees in Xishuangbanna National Nature Reserve of Yunnan Province and measured six tree shape structure indexes, eight leaf trait indexes, and habitat elements of regional topographic, meteorology, and soil. The effects and explantation of habitat elements on tree shape structure and leaf trait of B. ceiba were analyzed by structural equation model and variation decomposition. The results were as follows:(1)There were correlations among the indexes of tree shape structure and among the indexes of leaf trait(P < 0.05).(2)The observed indexes of habitat elements had a strong influence on the growth indexes of B. ceiba leaves. The mean annual precipitation, slope and average temperature had a higher interpretation rate on the growth indexes of B. ceiba leaves, and were the dominant habitat indexes affecting the growth of B. ceiba.(3)According to the standardized path coefficient, the three habitat elements had the same effects on tree shape structure and leaf trait of B. ceiba, and all of them were in the order of topographic element>meteorological element>soil element.(4)The superposition of three habitat elements explained that tree shape structure and leaf trait were 43.5% and 12.3%, respectively, indicating that the response of tree shape structure to habitat environment was greater than that of leaf trait to environment. The results of this study preliminarily explore the adaptation strategies of different growth indexes to environmental elements of B. ceiba, which provides theoretical basis and practical reference for the cultivation and propagation of B. ceiba in heterogeneous habitats and efficient management of B. ceiba plantation.