盐胁迫下胡杨胞内Cl-稳态平衡的形成及其受H2O2信号调控的机理研究

盐胁迫下，盐离子（Na+和Cl-）在植物胞质中过度积累对植物生长具有严重毒害作用，因此，研究盐离子的胞质脱毒机制对理解植物抗盐性形成具有重要意义。然而，国内外学者大多专注于胞质Na+脱毒机制的研究，而较少关注Cl-的脱毒过程，尤其是木本植物。本课题拟以耐盐木本植物胡杨（具有极强的胞质盐离子脱毒能力）作为单细胞研究模型，以盐敏感的群众杨做为对照，应用膜片钳，非损伤微测技术，荧光成像技术，X射线微区分析和荧光定量PCR等先进手段，从细胞-亚细胞层次探讨胡杨细胞质Cl-脱毒机制。研究内容包括胞质和液泡Cl-积累特征，质膜阴离子通道活性，液泡膜Cl-/H+转运活性，Cl-平衡相关基因表达，H2O2信号和质膜H+-ATPase在Cl-脱毒中的作用等方面。本课题力求揭示盐胁迫下胡杨胞内Cl-稳态平衡形成的调控机制，这将为理解木本植物胞内Cl-脱毒提供新证据，也为研究植物细胞Cl-跨膜运输提供了新思路。

Excess accumulation of Na+ and Cl- in the cytoplasma inhibits plant growth and development under salinity conditions. Thus, the studies on the mechanisms of cytoplasmic Na+ and Cl- detoxification are especially important for the understanding of plant salt tolerance. However, most studies are focus on the Na+ transport and detoxification while pay no attention to the process of cytosolic Cl- detoxification and this situation is more serious in woody plants. Populus euphratica exhibited a greater ability to regulate intracellular ion homeostasis under saline conditions and has been widely considered as a model plant to elucidate physiological and molecular mechanisms of salt tolerance in woody species. In this project, using a series of novel techniques, such as the patch clamp technique, the scanning ion-selective electrode technique, the fluorescence microscopic imaging techniques, the X-Ray microanalysis and real time PCR, we tend to investigate the mechanisms of cytosolic Cl- detoxification in salt-resistant Populus euphratica cells. Salt-sensitive Populus popularis cells were adopted as a comparison. We will investigate several contents in this project, including the characteristics of Cl- accumulating in the cytoplasma, activities of plasma membrane anion channels, activities of vacuolar Cl-/H+ antiport， gene expression related to the Cl- transport and the roles of H2O2 and plasma membrane H+-ATPase invovled in the process of cytosolic Cl- detoxification. This project put forwards a novel hypothesis that help to elucidating the mechanisms of intracellular Cl- homeostasis in Populus euphratica. This project is aslo important for the understanding of salt tolerance in woody plants.