NaCl-Induced Alternations of Cellular and Tissue Ion Fluxes in Roots of Salt-Resistant and Salt-Sensitive Poplar Species
NaCl-Induced Alternations of Cellular and Tissue Ion Fluxes in Roots of Salt-Resistant and Salt-Sensitive Poplar Species
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氯化钠诱导的抗盐和盐敏感杨树种根部细胞和组织离子通量的变化
DOI：
10.1104/pp.108.129494
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发表时间：
2009-02-01
期刊：
影响因子：
7.4
通讯作者：
Xu, Yue
中科院分区：
文献类型：
--
作者：
Sun, Jian;Chen, Shaoliang;Xu, Yue
采用扫描离子选择电极技术，研究了耐盐胡杨和盐敏感胡杨35-44(P.opoparis)根及其衍生原生质体中H+、Na+、Cl-的通量。与杨树相比，胡杨在短期暴露于50 mM氯化钠(24 H)和长期暴露于100 mM氯化钠(15 D)后，表现出更强的Na+排出能力。从长期胁迫的胡杨根中分离出的根原生质体，Na+外流增加，H+内流增加，特别是在酸性pH为5.5时。然而，Na+/H+逆向转运蛋白抑制剂阿米洛利和质膜H+-ATPase抑制剂原钒酸钠抑制了盐诱导的根组织和细胞的Na+/H+交换。这些结果表明，逆境下胡杨根中Na+的排出是质膜上Na+/H+逆向转运活跃的结果。相比之下，盐胁迫下的杨树根部Na+/H+逆向转运系统不足以在组织和细胞水平上排除Na+。此外，盐处理的胡杨根系比杨树具有更高的拒氯能力，特别是在高盐度下长期存在时。盐胁迫下胡杨根中H+、Na+、Cl-离子通量的变化规律与同质异构体甘露醇不同，说明盐胁迫引起的根离子通量变化主要是离子专一性作用的结果。
Using the scanning ion-selective electrode technique, fluxes of H+, Na+, and Cl- were investigated in roots and derived protoplasts of salt-tolerant Populus euphratica and salt-sensitive Populus popularis 35-44 (P. popularis). Compared to P. popularis, P. euphratica roots exhibited a higher capacity to extrude Na+ after a short-term exposure to 50 mM NaCl (24 h) and a long term in a saline environment of 100 mM NaCl (15 d). Root protoplasts, isolated from the long-term-stressed P. euphratica roots, had an enhanced Na+ efflux and a correspondingly increased H+ influx, especially at an acidic pH of 5.5. However, the NaCl-induced Na+/H+ exchange in root tissues and cells was inhibited by amiloride (a Na+/H+ antiporter inhibitor) or sodium orthovanadate (a plasma membrane H+-ATPase inhibitor). These results indicate that the Na+ extrusion in stressed P. euphratica roots is the result of an active Na+/H+ antiport across the plasma membrane. In comparison, the Na+/H+ antiport system in salt-stressed P. popularis roots was insufficient to exclude Na+ at both the tissue and cellular levels. Moreover, salt-treated P. euphratica roots retained a higher capacity for Cl- exclusion than P. popularis, especially during a long term in high salinity. The pattern of NaCl-induced fluxes of H+, Na+, and Cl- differs from that caused by isomotic mannitol in P. euphratica roots, suggesting that NaCl-induced alternations of root ion fluxes are mainly the result of ion-specific effects.