花生种子的发育与贮藏蛋白质的合成和积累

花生果针入土后16天(16 DAP),种子干重和鲜重开始迅速增加。整个发育阶段可分为5个时期:组织分化期(0～20 DAP)、成熟前期(21～28 DAP)、成熟中期(29～40DAP)、成熟中后期(41～62 DAP)和成熟后期(63～88DAP)。种子发芽率在成熟前期和中期迅速提高并到达最大值,而苗成活率在成熟中后期达到最大值,苗鲜重则以88 DAP种子的为最大。种子发育过程中,贮藏蛋白质的合成与积累模式与种子干重变化相似。SDS-PAGE分析表明,种子发育初期(16 DAP)子叶中已积累花生球蛋白和伴花生球蛋白I。双向凝胶电泳显示花生球蛋白各个亚基在20DAP时均已存在,伴花生球蛋白I的主要亚基在整个发育过程中其等电点有所变化,含量也逐渐增加。其他蛋白质在种子发芽力形成阶段(20～40 DAP)的变化较为显著。

Development and Storage Protein Accumulation in Peanut Seeds

The fruits of peanut (Arachis hypogaea L.) were harvested from the 8th to the 88th day after pegging (DAP). The experimental results indicated that the increase in fresh weight of pods and fresh and dry weight of seeds during development followed double sigmoid curves. The fresh weight of pods reached 90% of the maximum on the 20th DAP. Then the fresh and dry weights of seeds increased rapidly. Twenty two per cent of germination was obtained in dry-treated seeds on the 24th DAP. After that the germination capacity increased rapidly and reached a maximum on the 40th DAP. But the level of seed vigor reached its maximum only at the final stage of maturation. The developmental process of peanut seeds could be divided into five stages: tissue differentiation stage (0-20th DAP), early-maturation stage (21th-28th DAP), midmaturation stage (29th-40th DAP), mid-latematuration stage (41th-62th DAP) and late-maturation stage (63th-88th DAP). The accumulation pattern of salt-soluble protein was similar to that of dry weight of seeds during development. There was a close correlation between seed vigor and protein accumulation during seed maturation. Two-dimensional electrophoresis showed that major qualitative and quantitative changes in seed protein components gradually disappeared while the contents of others increased. Major changes in the polypeptide composition were observed during the acquisition of seed germinability. The arachin components were present in the very early stages of seed development.