论文部分内容阅读
淀粉降解代谢与种子萌发、叶片光合作用、块根贮藏及肉质果实的发育密切相关。α_淀粉酶是催化淀粉水解的重要酶之一 ,然而由于它在生活细胞中经常定位于叶绿体或质体之外 ,与淀粉基质在亚细胞水平上相互隔离 ,所以该酶在植物活体内的生理功能至今不完全清楚。研究表明 ,在苹果 (MalusdomesticaBorkhcv .Starkrimson)果实发育过程中 ,α_淀粉酶活性由低到高 ,与淀粉含量大致呈现互为消长的变化。Westernblotting实验证明 ,在果实发育过程中 ,α_淀粉酶的表观数量也是由少到多 ,与活性的变化一致。利用胶体金免疫电镜定位技术证明 ,果实内α_淀粉酶主要定位于质体内 ,其他亚细胞区域内α_淀粉酶分布很少 ;尤其在果实发育中后期 ,围绕质体内淀粉粒有高密度的α_淀粉酶分布 ,说明该酶主要分布于细胞内功能区域。α_淀粉酶优先定位于质体内的亚细胞分布特点在果实整个生长发育期没有变化。随着果实发育的推进 ,质体内胶体金分布密度显著增加 ,此结果与Westernblotting实验相互印证。推测α_淀粉酶参与了果实细胞内质体中淀粉的水解过程
Degradation of starch metabolism and seed germination, leaf photosynthesis, root tuberous storage and fruit development are closely related. Alpha-amylase is one of the important enzymes that catalyze the hydrolysis of starch, however, since it is often located in chloroplast or plastid in living cells, it is isolated from the starch matrix at the sub-cellular level, Physiological function is not yet fully understood. The results showed that during the fruit development of apple (Malus domestica Borkhcv. Starkrimson), the activity of α-amylase changed from low to high, and the content of starch showed roughly the same change with each other. Western blotting experiments showed that in the process of fruit development, the apparent amount of α-amylase is also from less to more, consistent with changes in activity. The results of colloidal gold immunoelectron microscopy showed that the α-amylase in fruit was mainly located in the plastid, and the distribution of α-amylase was very low in other subcellular regions. Especially in the middle and late stages of fruit development, α_ amylase distribution, indicating that the enzyme is mainly distributed in the intracellular functional area. The α-amylase preferentially localized in the plastid had no change in the fruit throughout its growth and development. With the advancement of fruit development, the density of colloidal gold in plastids increased significantly, which was confirmed by Western blotting experiments. It is speculated that α-amylase is involved in the hydrolysis of starch in the plastids of fruit cells