叶片水力性状研究进展

Recent advances in leaf hydraulic traits

叶片水力性状表征了叶片为适应外在环境而形成的水分传输方面的生存策略。叶片水力性状会限制整个植株的水分传输,并影响植物的气体交换及其对干旱的响应,因此关于叶片水力性状的研究已成为植物水分关系领域的研究热点之一。本文概括了叶片水力性状的基本指标(包括叶片整体水力导度(Kleaf)、叶片木质部水力导度(Kxylem)、叶片木质部外水力导度(Kout-xylem)等)和叶片水力导度的5种主要测量方法;总结了叶脉网络结构和环境因素对叶片水力性状的影响、叶片水力性状与叶片功能指标(气孔导度、叶片水势、叶片最大光合速率)的匹配与权衡关系,以及叶片水力性状与植物抗旱性关系的最新研究进展;对今后叶片水力性状的研究提出了两点建议:1)将叶片水力性状与气体交换和叶解剖结构等相结合,构建叶片碳-水耦合模型,揭示叶片应对外界环境变化而采取的生态策略,以及植物的水-碳投资机理;2)开展植株各部分(根-茎-叶)间水分传输的交互作用研究,筛选出水力系统高效安全的物种。

Leaf hydraulic traits represent the survival strategies of plant in leaf water transport when adapting to external environment. They constraint the whole plant＇ s water transport and af- fect its gas exchange and its response to drought. Therefore, studies on leaf hydraulic traits have been the research focus of plant-water relationship. In this paper, the basic indices of leaf hy- draulic traits, i.e. whole-leaf hydraulic conductance （Kleaf） , leaf xylem hydraulic conductance （ Kxylem ）, and leaf out the xylem hydraulic conductance （ Kout_xylem ） , and the five measuring meth- ods of leaf hydraulic conductance are summarized. Meanwhile, the research progresses are intro- duced, including the effects of leaf venation traits as well as the environmental factors on leaf hy- draulic traits, the trade-off relations between leaf hydraulic traits and leaf functional traits （ e. g. stomatal conductance, leaf water potential, leaf maximum photosynthetic rate）, and the relations between leaf hydraulic traits and drought resistance of plants. Two suggestions on further study of leaf hydraulic traits are proposed ： 1 ） combining the leaf hydraulic traits with gas exchange and anatomical structures of leaves, which is help for building a carbon-water coupling model on leaf scale, to further reveal the ecological strategies of leaves in response to the external environmental change and the plant water-carbon investment mechanism; 2） conducting the research on interac- tions between plant water transport systems （root-stem-leaf） in order to choose species with a safe and efficient water transport system.