欧李细胞器中电子流分配及活性氧代谢对干旱的响应机制

项目名称： 欧李细胞器中电子流分配及活性氧代谢对干旱的响应机制

项目编号： No.30800876

项目类型： 青年科学基金项目

立项/批准年度： 2009

项目学科： 金属学与金属工艺

项目作者： 宋兴舜

作者单位： 东北林业大学

项目金额： 18万元

中文摘要： 欧李是一种具有很强抗旱固沙能力的林木材料，但有关欧李对干旱的响应机理研究较少。项目围绕干旱胁迫条件下欧李幼苗光能分配、电子传递与亚细胞水平抗氧化响应进行研究。结果表明在干旱胁迫下，欧李叶绿体及线粒体内的电子传递的变化导致了更多的电子流向O2，进而引起了ROS（如H2O2）的增加。ROS（如H2O2）的增加诱导了亚细胞水平抗氧化酶整体上的增加，以清除过多ROS对植株造成的伤害。植株启动叶黄素循环，从而在PSII中将吸收的光能以热能的形式安全的耗散掉，保护PSII免受光破坏。VDE活性的升高有利于Z和A的积累，这样可以赋予植株更好的光保护能力和在恶劣环境下的生存能力。同时发现，外施AsA有效缓解了干旱胁迫下欧李叶片光合作用的下降，也缓解了Fv/Fm和Fv'/Fm '降低的程度，保持ΦⅡ#22312;胁迫期间的稳定性，还增加了叶黄素循环中Z的含量；一定浓度的光合菌（PSB）可以有效缓解干旱胁迫对欧李幼苗膜系统和PSⅡ#21453;应中心活性的伤害；线粒体内交替途径在植物体应对干旱胁迫中发挥了重要的作用。外源丙酮酸及外施琥珀酸能够降低植物体对干旱胁迫的敏感性，但二者在对呼吸的调节过程中存在不同步性。

中文关键词： 欧李；干旱；细胞器；叶黄素循环；抗氧化

英文摘要： Cerasus humilis is a species trees with strong capability of drought-resisting and sand-fixation, but there are few studies about the response mechanism to drought in C. humilis. The project revolves the studies of light energy distribution, electron transport and antioxidant response on drought stress in sub-cellular level in C. humilis seedlings. The results indicated that under drought stress, changes of electron transfer in the mitochondria and chloroplasts in C. humilis caused more electrons flowing to O2, which increased the contents of ROS (such as H2O2). The excess ROS (such as H2O2) increased antioxidant enzymes activities in the whole level in sub-cellular level, which in return, protected plants against damage from ROS. Plants triggered xanthophyll cycle, thus light energy absorbed in PSII can be dissipated securely as heat to protect PSII from the light damage. The increased activity of VDE contribute to the accumulation of Z and A, so that plants can be endowed with better photoprotection ability and the ability to survive in harsh environments. It is also found that exogenous AsA effectively relieves the decrease of photosynthesis under drought stress in C. humilis leaves and the extents of decreased Fv/Fm and Fv'/Fm ', which sustained the stability of ΦⅡin the course of stress, and also increased the contents of Z in xanthophyll cycle. At a certain concentration, photosynthetic bacteria (PSB) can effectively relieve the damage caused by drought stress to membrane system in C. humilis seedlings and activity of PSⅡreaction centre. The alternative respiration pathway in mitochondria played an important role in plants responses to drought stress. Exogenous pyruvic acid and exogenous succinic acid can reduce plants sensitivity to drought stress, but non-synchronization also existed.

英文关键词： Cerasus humilis ; drought; cell organelle; xanthophyll cycle; antioxidation