蚕豆保卫细胞原生质体质膜ABA结合蛋白与气孔对ABA敏感性的关系

在测定蚕豆(Vicia faba L.)保卫细胞原生质体质膜ABA结合蛋白的解离常数(Kd)和最大结合容量的基础上,进一步研究了几种因子(pH、光)对Kd和最大结合容量的影响。结果显示:pH并不改变结合蛋白的Kd值,而仅影响每个原生质体结合的分子数;光、暗处理的结果表明,光可使结合蛋白的Kd值增大,每个原生质体结合的ABA分子数减少,而暗处理可使结合蛋白的Kd值减小及每个原生质体结合的分子数增多,说明黑暗可提高气孔保卫细胞对ABA的敏感性,而光可以降低气孔保卫细胞对ABA的敏感性。因此,光、暗可以通过调节ABA结合蛋白的Kd值来调节气孔对ABA的敏感性。

RELATIONSHIP OF STOMATA SENSITIVITY TO ABA AND ABA BINDING PROTEINS ON THE PLASMALEMMA OF GUARD CELLS IN VICIA FABA

Based on the previous investigations of the dissociation constant and maximum binding capacity of ABA binding proteins per guard cell protoplast (GCP) in Viciafaba L., the authors have furthered their study in the effects of pH and light/dark on the activity of ABA binding proteins. The results showed that pH did not change the dissociation constant but at different pH the number of the bound ABA molecules per GCP was different. After illumination for 90 min the dissociation constant of the ABA binding proteins was increased and the ABA binding capacity per GCP was decreased. Both effects were reversed when GCPs were kept in fully dark for 90 min. The results indicated that the change of stomata sensitivity of ABA by light/dark could be regulated through the change of dis-sociation contant to the ABA binding proteins.