Residual transpiration as a component of salinity stress tolerance mechanism: a case study for barley.
Residual transpiration as a component of salinity stress tolerance mechanism: a case study for barley.
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DOI：
10.1186/s12870-017-1054-y
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发表时间：
2017-06-19
影响因子：
5.3
通讯作者：
Shabala S
中科院分区：
文献类型：
--
作者：
Hasanuzzaman M;Davies NW;Shabala L;Zhou M;Brodribb TJ;Shabala S
虽然大多数水分从叶表面通过气孔损失，但部分损失也通过叶角质层发生，即使气孔完全关闭。这一成分称为残余蒸腾，在夜间占主导地位，在干旱或盐碱等胁迫条件下也变得至关重要。因此，减少残余蒸腾可能是一个潜在的有用的机制，以提高植物的性能时，水的可用性减少（例如在盐或干旱胁迫条件下）。减少残余蒸腾作用的一种方法可能是通过增加叶片表面蜡的积累。不同叶龄、叶位以及不同基因型间的残馀蒸腾量和蜡质成分存在差异。本研究利用大麦耐盐性差异基因型，研究了残余蒸腾对大麦耐盐性的影响，并探讨了角质层蜡质在这一过程中的作用。使用三种不同位置（老的、中间的和年轻的）的叶。结果表明，老叶的残余蒸腾量高于幼叶，与渗透压呈负相关，与渗透势和叶水势呈正相关。在正常生长条件下，耐盐品种比敏感品种蒸腾更多的水分。大麦叶片角质层蜡质以伯醇为主（84.7-86.9%），还包括醛类（8.90-10.1%），正构烷烃（1.31-1.77%），苯甲酸酯（0.44-0.52%）、植醇相关化合物（0.22-0.53%）、脂肪酸甲酯（0.14-0.33%）、β-二酮（0.07-0.23%）和烷基间苯二酚（1.65-3.58%）。剩余蒸腾量与总蜡质含量呈显著负相关，与伯醇含量呈显著正相关。在充分灌溉条件下，大麦叶片渗透压和角质层蜡质总量都参与控制大麦叶片角质层失水。一个显着的和负相关的伯醇的量和残余蒸腾量之间的关系意味着一些角质层蜡质成分作为植物叶片表面的水分屏障，从而有助于耐盐胁迫。这表明，残余蒸腾可能是一个基本的机制，植物优化水分利用效率在胁迫条件下。本文的在线版本（doi：10.1186/s12870-017-1054-y）包含补充材料，可供授权用户使用。
While most water loss from leaf surfaces occurs via stomata, part of this loss also occurs through the leaf cuticle, even when the stomata are fully closed. This component, termed residual transpiration, dominates during the night and also becomes critical under stress conditions such as drought or salinity. Reducing residual transpiration might therefore be a potentially useful mechanism for improving plant performance when water availability is reduced (e.g. under saline or drought stress conditions). One way of reducing residual transpiration may be via increased accumulation of waxes on the surface of leaf. Residual transpiration and wax constituents may vary with leaf age and position as well as between genotypes. This study used barley genotypes contrasting in salinity stress tolerance to evaluate the contribution of residual transpiration to the overall salt tolerance, and also investigated what role cuticular waxes play in this process. Leaves of three different positions (old, intermediate and young) were used. Our results show that residual transpiration was higher in old leaves than the young flag leaves, correlated negatively with the osmolality, and was positively associated with the osmotic and leaf water potentials. Salt tolerant varieties transpired more water than the sensitive variety under normal growth conditions. Cuticular waxes on barley leaves were dominated by primary alcohols (84.7–86.9%) and also included aldehydes (8.90–10.1%), n-alkanes (1.31–1.77%), benzoate esters (0.44–0.52%), phytol related compounds (0.22–0.53%), fatty acid methyl esters (0.14–0.33%), β-diketones (0.07–0.23%) and alkylresorcinols (1.65–3.58%). A significant negative correlation was found between residual transpiration and total wax content, and residual transpiration correlated significantly with the amount of primary alcohols. Both leaf osmolality and the amount of total cuticular wax are involved in controlling cuticular water loss from barley leaves under well irrigated conditions. A significant and negative relationship between the amount of primary alcohols and a residual transpiration implies that some cuticular wax constituents act as a water barrier on plant leaf surface and thus contribute to salinity stress tolerance. It is suggested that residual transpiration could be a fundamental mechanism by which plants optimize water use efficiency under stress conditions. The online version of this article (doi:10.1186/s12870-017-1054-y) contains supplementary material, which is available to authorized users.