Conservative water use under high evaporative demand associated with smaller root metaxylem and limited transmembrane water transport in wheat
Conservative water use under high evaporative demand associated with smaller root metaxylem and limited transmembrane water transport in wheat
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DOI：
10.1071/fp13211
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发表时间：
2014-01-01
影响因子：
3
通讯作者：
Sadok, Walid
中科院分区：
文献类型：
--
作者：
Schoppach, Remy;Wauthelet, Diego;Sadok, Walid
抗旱小麦的高效育种基因型需要识别特殊表现背后的机制。有证据表明，耐旱育种系RAC 875是水分利用保守，限制其蒸腾速率（TR）的敏感性，增加蒸汽压赤字（VPD），从而节省土壤水分供以后使用。然而，这种反应的生理基础仍然未知。在12个独立的水培和盆栽试验中，研究了RAC 875和干旱敏感品种（Kukri）的叶和根发育、解剖和水力特征在调节高VPD、全株TR中的参与。叶面积和气孔密度被发现是相同的线和去根植物之间没有表现出差异TR响应VPD或TR敏感性四个水通道蛋白（AQP）抑制剂，包括氯化汞（HgCl 2）。然而，完整的植物表现出差异的敏感性，氯化汞，部分逆转β-巯基乙醇。此外，RAC 875的根导水率低于Kukri的根导水率，并且RAC 875的根横截面中柱和中央木质部直径显着较小。这些结果表明，水的保护RAC 875的结果从根为基础的水力限制，需要潜在的遗传功能和解剖特征。这项研究揭示了在蒸发需求增加的情况下，解剖学和基于AQP的过程在调节TR方面的联系。
Efficient breeding of drought-tolerant wheat (Triticum spp.) genotypes requires identifying mechanisms underlying exceptional performances. Evidence indicates that the drought-tolerant breeding line RAC875 is water-use conservative, limiting its transpiration rate (TR) sensitivity to increasing vapour pressure deficit (VPD), thereby saving soil water moisture for later use. However, the physiological basis of the response remains unknown. The involvement of leaf and root developmental, anatomical and hydraulic features in regulating high-VPD, whole-plant TR was investigated on RAC875and a drought-sensitive cultivar (Kukri) in 12 independent hydroponic and pot experiments. Leaf areas and stomatal densities were found to be identical between lines and de-rooted plants didn't exhibit differential TR responses to VPD or TR sensitivity to four aquaporin (AQP) inhibitors that included mercury chloride (HgCl2). However, intact plants exhibited a differential sensitivity to HgCl2 that was partially reversed by beta-mercaptoethanol. Further, root hydraulic conductivity of RAC875 was found to be lower than Kukri's and root cross-sections of RAC875 had significantly smaller stele and central metaxylem diameters. These findings indicate that the water-conservation of RAC875 results from a root-based hydraulic restriction that requires potentially heritable functional and anatomical features. The study revealed links between anatomical and AQP-based processes in regulating TR under increasing evaporative demand.