Water transport from stem to stomata: the coordination of hydraulic and gas exchange traits across 33 subtropical woody species.

IF 3.5 2区农林科学 Q1 FORESTRY

Tree physiology Pub Date : 2019-10-01 DOI:10.1093/treephys/tpz076

Xiaorong Liu, Hui Liu, S. Gleason, G. Goldstein, Shidan Zhu, Pengcheng He, Hao-Bo Hou, Ronghua Li, Q. Ye

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引用次数: 13

Abstract

Coordination between sapwood specific hydraulic conductivity (Ks) and stomatal conductance (gs) has been identified in previous studies, however, coordination between leaf hydraulic conductance (Kleaf) and gs, as well as between Kleaf and Ks is not always consistent. This suggests that there is a need to improve our understanding of the coordination among hydraulic and gas exchange traits. In this study, hydraulic traits (e.g., Ks and Kleaf) and gas exchange traits, including gs, transpiration (E), and net CO2 assimilation (Aarea) were measured across 33 co-occurring subtropical woody species. Kleaf was divided into two components: leaf hydraulic conductance inside the xylem (Kleaf-x) and outside the xylem (Kleaf-ox). We found that both Kleaf-x and Kleaf-ox were coordinated with gs and E, but the correlation between Kleaf-ox and gs (or E) were substantially weaker, and that Ks was coordinated with Kleaf-x, but not with Kleaf-ox. In addition, we found that Ks, Kleaf-x and Kleaf-ox together explained 63% of the variation in gs and 42% of the variation in Aarea across species, with Ks contributing the largest proportion of explanatory power, whereas Kleaf-ox contributing the least explanatory power. Our results demonstrate that the coordination between leaf water transport and gas exchange, as well as the hydraulic linkage between leaf and stem, were weakened by leaf outside-xylem hydraulic conductance. This highlights the possibility that water transport efficiencies of stem and leaf xylem, rather than that of leaf tissues outside the xylem, are important determinants of stomatal conductance and photosynthetic capacity across species.

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从茎到气孔的水分输送:33种亚热带木本植物水力和气体交换特性的协调。

在以往的研究中已经发现了边材比水力导率(Ks)与气孔导度(gs)之间的协调关系，但是叶片比水力导率(Kleaf)与gs之间以及叶片比水力导率与气孔导度之间的协调关系并不总是一致的。这表明有必要提高我们对水力和气体交换特性之间协调的认识。本研究测量了33种亚热带共生木本植物的水力性状(如Ks和Kleaf)和气体交换性状(如gs、蒸腾(E)和净CO2同化(Aarea))。叶片的水力导度分为木质部内叶导度(Kleaf-x)和木质部外叶导度(Kleaf-ox)两部分。我们发现，Kleaf-x和Kleaf-ox都与gs和E协同，但与gs(或E)的相关性明显较弱，Ks与Kleaf-x协同，而与Kleaf-ox不协同。此外，我们发现Ks、Kleaf-x和Kleaf-ox共同解释了物种间63%的gs变异和42%的面积变异，其中Ks贡献的解释力最大，而Kleaf-ox贡献的解释力最小。结果表明，叶片外木质部的水力传导减弱了叶片水分输送和气体交换的协调性以及叶片与茎的水力联系。这强调了一种可能性，即茎和叶木质部的水分输送效率，而不是木质部外的叶组织的水分输送效率，是物种间气孔导度和光合能力的重要决定因素。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Tree physiology 农林科学-林学

CiteScore

7.10

自引率

7.50%

发文量

133

审稿时长

1 months

期刊介绍： Tree Physiology promotes research in a framework of hierarchically organized systems, measuring insight by the ability to link adjacent layers: thus, investigated tree physiology phenomenon should seek mechanistic explanation in finer-scale phenomena as well as seek significance in larger scale phenomena (Passioura 1979). A phenomenon not linked downscale is merely descriptive; an observation not linked upscale, might be trivial. Physiologists often refer qualitatively to processes at finer or coarser scale than the scale of their observation, and studies formally directed at three, or even two adjacent scales are rare. To emphasize the importance of relating mechanisms to coarser scale function, Tree Physiology will highlight papers doing so particularly well as feature papers.