不同海拔华北落叶松细根形态特征

Fine root morphology characteristics of Larix principis-rupprechtii along an elevation gradient

山地海拔变化包含多个环境因子的梯度效应，而细根作为植物重要的功能器官，对环境因子变化较为敏感。因此，了解植物细根形态特征对海拔变化的响应对于认识气候变化下的植物地下过程具有重要意义。本研究以山西省庞泉沟国家自然保护区内分布于1800～2700m海拔上的华北落叶松（L0r如principis-rupprechtii）细根为研究对象，采用根序分级法对不同根序细根形态特征（直径、比根长、比表面积和组织密度）进行了分析，结果表明：（1）同级根序细根直径随海拔升高而增粗，组织密度随海拔升高而减小，比根长和比表面积则随海拔升高先增加后减小；（2）不同海拔处细根形态均表现随序级增加，直径和组织密度变大，而比根长和比表面积减小；（3）分析表明，海拔、根序变化均显著影响细根形态特征（P〈O．05），但海拔和根序的交互作用只对细根直径和组织密度变化有显著影响（P〈O．05）；其中1～3级根直径和组织密度均与海拔变化显著相关（P〈0．05），而4、5级根序各形态特征与海拔之间的相关性均不显著。本研究结果可为进一步认识植物细根对未来气候变化下的响应机制提供重要参考。

Mountain altitudinal gradient contains the changes of multiple environmental parame- ters, and fine roots, functioning as the basis of plants in absorbing water and nutrient, are sensi- tive to these environmental changes. In this study we investigated the response of fine root mor- phology to the altitudinal gradient in the Panquangou National Nature Reserve in Shanxi Prov- ince, northern China, to improve our understanding of the underground processes of plants in the context of global environmental change. We measured the variations of root morphology, including diameter, root tissue density, specific root length and specific root surface area, among different root orders for Larix principis-rupprechtii （ distributed in 1800-2700 m above sea level）. The data showed that （1） For the same root order, with the elevation increasing, root diameter increased and root tissue density （RTD） decreased, while specific root length （SRL） and specific root sur- face area （SRA） showed low values at the low and high elevations; （2） At each altitude, root diameter and RTD increased along with the root order increasing, but SRL and SRA declined; （3） The analysis of variance showed that altitude and root order significantly influenced the mor- phology of fine roots （P 〈 0.05）, and they interacted to exert influence on the root diameter and RTD only （P〈0.05）. For the first three root orders, root diameter and RTD were closely related with the altitude （P 〈 0.05）. However, for the fourth and fifth root orders, the correlation be- tween altitude and the four morphology characteristics was not significant. These results are im- portant for understanding the mechanism of response of fine roots to future climate change.