小兴安岭不同耐荫性树种枝叶性状变异及权衡

随着植株生长，不同耐荫性树种枝叶性状对资源的响应策略存在差异。探究不同耐荫性树种在不同径级间枝叶性状变异及其相关关系，对理解植物功能性状种内和种间变异以及植物对资源的响应策略具有重要意义。以黑龙江凉水国家级自然保护区阔叶红松（Pinus koraiensis）林中不同径级（小树、中等树和大树）的喜光树种（白桦Betula platyphylla、枫桦Betula costata）和耐荫树种（春榆Ulmus japonica、紫椴Tilia amurensis、色木槭Acer mono）为研究对象，测定其出叶强度、枝横截面积、枝干重、单叶面积、总叶面积、总叶干重共6个枝叶性状。利用单因素方差（LSD）分析检验不同耐荫性树种在不同径级间其枝、叶性状是否存在显著差异；以标准化主轴估计（SMA）对不同耐荫性树种枝叶性状间相关关系进行分析。结果表明：除枝干重外，耐荫树种枝叶性状均大于喜光树种；不同耐荫性树种大树枝横截面积均最大，中等树叶面积均最小；喜光树种不同径级间枝干重、总叶干重和出叶强度无显著差异，而耐荫树种均存在显著差异。随径级增大，不同耐荫性树种枝横截面积与叶面积均呈正异速生长关系，且除耐荫树种枝横截面积与单叶面积外，均存在共同斜率；不同耐荫性树种出叶强度与单叶面积存在共同斜率为-0.51和0.47，小树和中等树枝横截面积与总叶面积和总叶干重的异速生长指数均与1存在显著差异，而大树与1无显著差异。结果表明：不同耐荫性树种在不同径级间对资源的获取策略存在差异，不同耐荫性树种小树阶段均表现出资源获取策略，大树阶段则表现出资源保守型策略。与耐荫树种相比，喜光树种表现为快速生长策略，而随着径级增大不同耐荫性树种这种差异逐渐消失，本研究结果为森林演替过程中种内和种间的相互作用提供了一个新的视角。

Variation and trade-off of twig and leaf traits of different shade tolerance species in Xiaoxingan Mountains

The response strategies of twig-leaf traits to resources varied with plant growth. Exploring the variation and correlation of twig and leaf traits of different functional tree species in different diameter classes is of great significance for understanding the variation of plant functional traits within species (diameter class) and between species (shade tolerant) and the response strategy of plants to resources. In Liangshui National Nature Reserve of Heilongjiang Province. Small, medium, and large trees of shade intolerant tree species (Betula platyphylla and Betula costata) and shade-tolerant tree species (Ulmus japonica, Tilia amurensis, and Acer mono) were selected. The volume-based leafing intensity, twig cross-sectional area, twig dry weight, individual leaf area, total leaf area, and total leaf dry weight were measured. One-way analysis of variance (ANOVA) was used to test whether there were significant differences between different diameter classes and different functional types. The method of standardized major axis (SMA) was used to test the effect of diameter class and functional type on the correlation between twig-leaf traits. Result indicates that:all shade-tolerant species had greater twig and leaf traits than shade-intolerant species, except for twig dry weight; all shade-tolerant species had the largest twig cross-sectional area in large trees and the smallest leaf area in middle trees; there were no significant differences in twig dry weight, total leaf dry weight, and the volume-based leafing intensity among different diameter classes of shade-intolerant species, while all shade-tolerant species had significant differences. As the diameter of the tree increases, there is a positive anisotropic growth relationship between twig cross-sectional area and leaf area for different shade-tolerant species, with the exception of shade-tolerant species, where there is a common slope between twig cross-sectional area and individual leaf area; the volume-based leafing intensity and individual leaf area for different shade-tolerant species have a common slope of -0.51 and -0.47, and the anisotropic growth indices of twig cross-sectional area and total leaf area and total leaf dry weight for small and middle trees are significantly different from 1, while large trees are not significantly different from 1. The results showed that different shade-tolerant species and their resource acquisition strategies differ between different diameter classes, with all shade-tolerant species showing a resource acquisition strategy at the small tree stage and a resource conservative strategy at the large tree stage. The shade-intolerant species showed a fast growth strategy compared to the shade-tolerant species, and the difference between shade-intolerant and shade-tolerant species gradually disappeared as the diameter level increased. The results provide a new perspective on intraspecific and interspecific interactions during forest succession.