不同叶习性树种木质部功能性状相似且与其导管间纹孔结构密切相关

Xylem functional traits of tree species with different leaf habits aresimilar and closely related to the intervessel pit structure

研究木质部的结构及功能性状有助于预测植物对干旱事件的响应。为探究安徽省潜山市板仓自然保护区常绿和落叶树种木质部超微结构及水力性状差异及关系,采用多种显微技术结合的方式对生长于板仓自然保护区内的八个优势树种的枝条木质部超微结构进行观测并对枝条的水力性状进行了测量。研究结果表明:(1)以叶习性进行分组的两个类群里,常绿树种和落叶树种之间的解剖结构和水力性状高度相似,不存在统计学差异。(2)八个树种水分运输的安全性和效率性之间存在显著权衡关系,其中大果山胡椒抗栓塞能力最强(P_(50)=-1.69 MPa),青榨槭抗栓塞能力最弱(P_(50)=-0.90 MPa)。(3)八个树种的P50值与纹孔口直径和纹孔膜直径之间呈正相关关系,与木质部机械强度(导管壁加固系数、木材密度)、纹孔膜厚度以及纹孔膜厚度与直径的比值之间呈负相关关系,与导管直径、导管密度、导管群指数和导管接触比例之间无相关性。本研究为板仓自然保护区的引种、选种及森林保护提供了一定依据。

Studying the structural and functional traits of xylem is helpful to predict the response of plants to drought events.In order to explore the difference and relationship between xylem ultrastructure and hy-draulic traits of evergreen and deciduous tree species in Bancang Nature Reserve of Qianshan City,Anhui Province,this study used a combination of various microscopic techniques to observe the xylem ultra-structure of branches of eight dominant tree species growing in Bancang Nature Reserve and measure the hydraulic traits of branches.The results were as follows:(1)In the two groups grouped by leaf habits,the anatomical structure and hydraulic traits of evergreen tree species and deciduous tree species were highly overlapped,and there was no statistical difference.(2)There was a trade-off between safety and efficiency of water transport,with Lindera praecox being the most resistant to embolism(P_(50)=-1.69 MPa)and Acer davidi being the least resistance to embolism(P_(50)=-0.90 MPa).(3)Pso values in eight species showed a positive correlation with the pit aperture diameter and pit membrane diameter,but a negative correlation with conduct wall reinforcement,wood density,pit membrane thickness and the radio of the pit membrane thickness to diameter.There was no correlation between Pso and vessel diameter,vessel density,vessel-grouping index and intervessel contact fraction.This study provides a basis for introduction and selection of tree species and forest protection in Bancang Nature Reserve.