树木管胞大小对于西伯利亚南部林草交错带森林生长及环境适应性的指示意义

为了研究木质部细胞、树木个体和森林群落3个尺度之间的关联, 在西伯利亚南部以西伯利亚落叶松(Larix sibirica)和欧洲赤松(Pinus sylvestris)为主的3个采样点37个样地, 测量725根树芯的树木年轮宽度, 采用系统随机的方法选择其中195个树芯进行管胞大小的测量和计算。结果表明, 尽管局地环境和树种组成有所不同, 但在树木个体和森林群落两个水平上, 管胞大小与树木径向生长的年际变化显著相关。较小的平均管胞尺寸指示更低的年际生长量和更高的年际生长波动。平均管胞大小对半干旱区针叶林生境湿度和森林生长适应性具有指示作用, 揭示树木通过调节管胞的大小在生长适应与生长安全性二者间的权衡机制。

Indicative Significance of Tree Tracheid Size on Forest Growth and Environmental Adaptability in the Forest-Grass Ecotone of Southern Siberia

In order to study the relationship of three growth features of cell, tree and forest that indicate adaptation of trees to water deficit, we measured the tree-ring widths of 725 tree-cores sampled from sites dominated by Larix sibirica and Pinus sylvestris and then 195 of them were randomly selected to measure the tracheid size. The results show that the tracheid size is significantly correlated to the radial growth and the inter-annual variation in ring width, at both levels of the tree individual and forest community, regardless of local environment and tree species. This result suggests that small mean tracheid cells indicate low growth rate and more growth variation. The study implies that the mean tracheid size could serve as a robust indicator of tree or forest adaptation to habitat humidity for conifers in the semi-arid region and reveals the trade-off between growth adaptation and growth safety of trees by regulating tracheid size. As an important xylem trait of conifer forests, the size of tracheid is valuable for the further physiological study of drought adaptation of trees in the semi-arid region.