东灵山不同林型五角枫叶性状异速生长关系随发育阶段的变化

分析植物叶片性状种内水平的异速生长关系有助于加深理解生长发育过程中叶片的资源利用模式.分析了东灵山3个主要林型(白桦林、胡桃楸林、辽东栎林)中五角枫成树、幼树、幼苗的叶面积、叶体积、叶含水量与叶干重之间的异速生长关系.结果表明:成树叶面积增长速度小于叶干重的增长速度,幼树、幼苗叶面积与叶干重保持同速增长;成树、幼树叶干重与叶体积保持同速增长,幼苗叶体积的增长速度超过了干重的增长速度;成树叶含水量的增长速度小于叶干重的增长速度,幼树、幼苗两性状间保持等速增长.叶含水量与叶干重的异速生长指数在不同的林型间有显著差异,白桦林叶含水量的增长速度小于叶干重的增长速度,其余两个林型均为等速增长趋势.这些结果揭示了不同发育阶段五角枫资源利用方式的转变.随叶干重的增加,成树将更多的叶生物量投资于同化和支持结构;幼树则保持对光合面积和光合同化结构的稳步投资;而幼苗主要投资于叶面积的增大.叶含水量与叶干重的异速曲线在不同林型间的差异说明叶片代谢活性相较于其他叶性状可塑性更高.

Changes of allometric relationships among leaf traits in different ontogenetic stages of Acer mono from different types of forests in Donglingshan of Beijing

This study focused on the allometric relationships of the leaf traits of Acer mono at different life stages in various forest types, to explore the resource utilization strategy of A. mono across various life stages and environmental conditions. The lamina mass, lamina area, lamina volume and lamina water content of A. mono adults, saplings and seedlings at three forests, Betula platyphylla forest, Juglans mandshurica forest and Quercus wutaishanica forest, were measured in Donglingshan, Beijing. The standardized major axis estimation method was used to examine the scaling relationships among leaf traits of A. mono. The increasing rate of lamina area was lower than that of lamina mass in adult trees, but they maintained the same growth rate in saplings and seedlings.The lamina volume of the seedling grew faster than its lamina mass. The increasing rate of lamina mass kept pace with that of lamina volume in both adult trees and saplings. An increase in lamina water content was slower than that in lamina mass in adult trees. The similar increasing rates between lamina water content and lamina mass were found for both saplings and seedlings. In the different forest types, the scaling relationship between lamina water content and lamina mass was statistically different. The increasing rate of lamina water content was less than that of lamina mass of A. mono in B. platyphylla forest. However, they were isometric in J. mandshurica and Q. wutaishanica forests. These results suggested the pattern of resource utilization shifted across various life stages of A. mono. With an increase in lamina mass, A. mono adult trees invested more leaf biomass in assimilation and supporting structure, and saplings maintained steady investments of light-harvesting area and photosynthetic assimilating structure, while seedlings mainly increased leaf area. The difference in allometric index of both lamina water content and mass among different forest types to some extent reflected that leaf metabolic activity was strong plasticity in comparison to other leaf traits.