Root functional change achieves water source separation under vegetation succession
Root functional change achieves water source separation under vegetation succession
复制标题
根系功能变化实现植被演替下的水源分离
DOI：
10.1002/eco.1985
复制
发表时间：
2018
期刊：
影响因子：
2.6
通讯作者：
Yamanaka Tsutomu
中科院分区：
文献类型：
--
作者：
Tonoyama,M.;Seki,M.;Sonoda,N.;and Okayama,T.;Yamanaka Tsutomu
水源分离可能是不同植物物种在群落中共存的策略之一。本研究首次揭示了植被演替过程中水源分离的机制。采用同位素结合的机制模型，模拟了密林栎-密栎混交林次生演替和纯密林演替前的木质部水分同位素组成和根系水分吸收剖面。在混合林分中，该模型成功地模拟了木质部水分同位素组成，假设密花的单位长度根表面阻力（rrs*）随深度的增加而减小，而密叶的单位长度根表面阻力（rrs*）不变。密花的吸收分数在较深的带中较大，而在较浅的带中较大。相比之下，在纯林分中，p . densifloragr的常数*在同位素模拟和浅水吸收方面具有良好的再现性。这些发现强调了根系功能变化是水源分离的机制；已存在的密花树减少其深根生长*以补偿浅根生长*的增加。这一机制是由入侵的紫杉树的竞争引起的。
Water source separation can be one of strategies for different plant species to coexist in a community. This study first demonstrates mechanisms of water source separation during vegetation succession. An isotope‐incorporated mechanistic model was employed to simulate the xylem water isotopic composition and the root water uptake profile for aPinus densiflora–Quercus myrsinaefoliamixed stand undergoing secondary succession and a pureP.densiflorastand before succession. In the mixed stand, the model successfully simulated the xylem water isotopic composition on the assumption that the root surface resistance per unit length of root (rrs*) decreases with increasing depth forP.densiflorabut is constant forQ.myrsinaefolia. Uptake fraction forP.densiflorawas greater in deeper zones but in shallower forQ.myrsinaefolia. In contrast, in the pure stand, a constantrrs*forP.densifloragave good reproducibility in isotope simulation and shallow water uptake dominated. These findings highlight root functional change as a mechanism of water source separation; pre‐existingP.densifloratrees decrease their deep‐rootrrs*to compensate for an increase in shallow‐rootrrs*. This mechanism was caused by competition against invadingQ.myrsinaefoliatrees.