摘要
渗透胁迫降低了叶片、特别是生长叶片蛋白质中固定^(14)CO_2及由根系吸收的^(14)C-Gly的掺入率,但同等程度胁迫处理,抗旱品种的掺入率降低幅度小于敏感品种;轻度胁迫后复水,抗旱品种生长叶蛋白质的放射性高于对照,而敏感品种仍低于对照。Poly(A^+)-mRNA的体外翻译测定证明,胁迫时蛋白质合成能力降低的主要原因是Poly(A^+)-mRNA翻译活性的降低。渗透胁迫也促进了叶片蛋白质降解,但与蛋白质合成不同,在成熟叶片中表现得更突出。
Effects of osmotic stress with PEG-6000 solution (--1.0 MPa) on protein synthesis and degradation in the leaves of Triticum aestivum L cv. Zhenyin No.1 (sensitive cultivar) and Shaanhe No.6 (resistant cultivar) were studied by tracer methods. It was found that osmotic stress decreased the incorporation of assimilated ^(14)CO_2 and ^(14)C-Gly into leaf proteins of both cultivars, but the degree of decrease of incorporation in the leaves of Shaanhe No.6 was lower than that of Zhenyin No.1. In addition, the effect of osmotic stress on protein synthesis of matured leaves was lighter than on that of growing leaves. After mild stress and then rewatering, the incorporation of radioactivity in the growing leaves of Shaanhe No.6 was greater than that of control. The results of in vitro translation of Poly (A+)-mRNA indicated that the decrease of protein synthesis was mainly due to the decrease in the translation activity. Tracer kinetics analysis showed that osmotic stress enhanced the degradation of leaf proteins. The half-lives of proteins in matured leaves of Shaanhe No.6 and Zhenyin No.1 shortened from 173 h and 168 h of control to 137 h and 119 h, respectively during osmotic stress; while in the growing leaves, they shortened from 183 h and 184 h to 167 h and 176 h, respectively.
基金
国家自然科学基金
关键词
小麦
渗透胁迫
蛋白质合成
降解
wheat
osmotic stress
tracer
protein synthesis
protein degradation
in vitro translation
