华北低山丘陵区常用树种木质部解剖特征及水其力学抗旱性

木本植物木质部解剖特征与水分运输和干旱适应策略密切相关,但目前对华北低山丘陵区常用树种这方面的研究仍然不足。为研究这一地区植物木质部解剖特征与抗旱性的关系,研究以抗旱树种和非抗旱树种各5种为研究对象,通过测定与木质部横截面导管、薄壁组织相关的大量解剖学性状和非结构性碳浓度,比较两类树种木质部解剖特征的差异和解剖性状间的关联,以探究这些树种水力学的干旱适应策略差异。结果显示:1)10个树种的16个木质部性状均有较大变异性;2)两类树种间的平均导管直径和导管密度无显著差异,但抗旱树种导管壁厚度、最大导管直径、旁管薄壁组织比例和轴向薄壁组织比例以及非结构性碳(NSC)浓度显著大于非抗旱树种;3)抗旱树种的导管壁厚度与平均导管直径、最大导管直径和潜在最大导水率均呈显著正相关关系,最大导管直径与潜在最大导水率呈显著正相关关系,但非抗旱树种不存在这些关系。本研究抗旱树种同时具有较大的最大导管直径和较厚的导管壁,在保证较高的水分运输效率的同时又具备一定的抗栓塞能力,较多的旁管薄壁组织和NSC也为抗旱树种提供了更大的木质部水储存和栓塞修复能力。

Xylem anatomical and hydraulic drought resistance characteristics of common tree species in hilly areas of North China

The xylem anatomical characteristics of woody plants are closely related to water transport and drought adaptation strategies. However, the research on the commonly used tree species in the hilly areas of North China is still insufficient. In order to study the relationship between xylem anatomical characteristics and drought resistance, this paper takes the common tree species in North hina as the research object, 10 tree species were classified into drought-resistant tree species and non-drought-resistant tree species. By measuring the xylem cross section vessel, a large number of anatomical properties related to parenchyma, non-structural carbon concentration, the differences of anatomical characteristics of xylem and the relationship between anatomical characters of the two types of tree species were compared to explore the differences of hydraulic drought adaptation strategies of these species. The results showed that: 1) all 16 xylem characters of 10 species showed great variability. 2) There was no significant difference in the mean vessel diameter and the vessel density between the two groups, but the vessel wall thickness, the maximum vessel diameter and others of drought-resistant tree species were significantly higher than those of non-drought-resistant tree species. 3) There was a significantly positive correlation between the vessel wall thickness and the mean vessel diameter, the maximum vessel diameter and the potential hydraulic conductance of drought-resistant tree species, and a significantly positive correlation between the maximum vessel diameter and the potential hydraulic conductance, however, these relationships did not exist in non-drought-resistant tree species. Drought-resistant tree species have large maximum vessel diameter and vessel wall thickness at the same time, which not only ensure higher water transport efficiency, but also have certain anti-embolism ability. More paratracheal parenchyma and the non-structural carbohydrate(NSC) also provide greater xylem water storage and refilling of embolism capacity for the drought-resistant tree species.