花生种子贮藏蛋白质与活力的关系及其在萌发时的降解模式

THE RELATION OF STORAGE PROTEIN TO VIGOR AND ITS MOBILIZATION PATTERN IN GERMINATING PEANUT SEEDS

本文测定了按大小分作5个级别的成熟花生(Arachis hypogaea L.)种子的总蛋白、盐溶蛋白,花生球蛋白、伴花生球蛋白Ⅰ和2s 球蛋白的含量。花生种子的贮藏蛋白质与活力之间有很高的相关性。在种子萌发和幼苗生长过程中,子叶中的盐溶蛋白质全部被利用。SDS-聚丙烯酰胺凝胶电泳结果表明,花生球蛋白中分子量为23.5、38.5和41kD 的亚基首先被分解,而18kD 亚基最后被分解。伴花生球蛋白60.5kD 亚基在萌发初期被利用,2s 球蛋白则在萌发后2～3天开始降解。

The peanut (Arachis hypogaea L.) seeds harvested at the last stage of maturation were di- vided into five grades by size. The content of total protein, salt-soluble protein, arachin, cona- rachin I and 2_s globulin in these seeds were measured. No obvious differences in germination percentage and the length of radicle and hypocotyl within 3d germination in dark were ob- served among the five grades of seeds. But there were significant differences in the seedling growth after two weeks of germination in light. There was a very close correlation between the storage protein in cotyledons and the seedling growth. When seeds germinated in light, the efficiency of mobilization of the salt-soluble protein in the cotyledons was higher than that in the cotyledons of the seeds germinating in dark. All of the salt-soluble protein in cotyledons was used up after 14d seedling growth in light. SDS-PAGE of salt-soluble protein showed that 23.5, 38.5 and 41 kD subunits of arachin were first mobilized during germination. The ls kD subunits of arachin were not mobilized until the above-mentioned subunits were used up. The 60.5 kD su- bunit of conarachin I and 2_s globulin were degradated within 2 to 3 days during germination.