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Mechanism of Salinity Stress and Its Countermeasures in Crop Plants

农作物盐胁迫机理及对策

基本信息

批准号：
15208002
负责人：
MIYAKE Hiroshi
金额：
$ 33.86万
依托单位：
Nagoya University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2005
项目状态：
已结题

项目摘要

When the effects of salinity stress and water stress were compared in rice, damages in chloroplasts were more prominent in salinity stress. Typical symptom of salinity stress was swelling of the thylakoids. Damages in chloroplasts by salinity were severer in light than in the dark even if Na and Cl concentrations and Na/K ratio in the leaf tissues were comparable or higher in the dark. Therefore, the damages in chloroplasts induced by salinity were dependent on light and the involvement of reactive oxygen species (ROS) was suggested. Pretreatment of leaf tissues with ascorbate (versatile scavenger of ROS including H_2O_2) and benzoate (scavenger of ・OH) was effective to reduce damages in chloroplasts by salinity. It is therefore suggested that the damages were caused by ・OH and/or its precursor H_2O_2. Growth inhibition of rice plants by salinity was ameliorated by Ca^<2+> in hydroponic culture but K^+ was more effective in soil culture. Especially, KNO_3 showed ameliorative effects on the yield of rice. There was a strong correlation between growth inhibition and Na/K ratio in the shoot. Therefore, cultivation practice to reduce Na/K ratio in the shoot is effective to reduce salinity stress. Pretreatment of leaf tissues with a low concentration of methyl viologen (ROS producing herbicide) reduced damages in chloroplasts by salinity and increased the activity of ascorbate peroxidase in the leaf. Therefore, treatments to reduce H_2O_2 concentration in the leaf are effective to ameliorate salinity stress.

当比较盐胁迫和水分胁迫对水稻的影响时，盐胁迫对叶绿体的损伤更为突出。盐分胁迫的典型症状是类囊体肿胀。盐胁迫对叶绿体的伤害在光照条件下比在黑暗条件下更为严重，即使在黑暗条件下叶片组织中的Na、Cl浓度和Na/K比相当或更高。因此，盐分诱导的叶绿体损伤依赖于光，并提出了活性氧自由基(ROS)的参与。用抗坏血酸(包括H_2O_2等多种ROS清除剂)和苯甲酸(·OH清除剂)处理叶片组织，可以有效地减轻盐胁迫对叶绿体的伤害。在水培条件下，Ca~(2+)~(2+)和Gt~(2+)对水稻植株生长的抑制作用有所改善，而在土壤培养条件下，K~(2+)的作用更为明显。其中，硝酸钾对水稻产量有明显的增产作用。生长抑制率与地上部Na/K值有很强的相关性。因此，降低地上部Na/K比的栽培措施对缓解盐分胁迫是有效的。用低浓度甲基紫精(产生ROS除草剂)处理叶片组织，可减轻盐胁迫对叶绿体的伤害，提高叶片抗坏血酸过氧化物酶活性。因此，降低叶片中H_2O_2浓度的处理对缓解盐分胁迫是有效的。