宁夏枸杞果实发育过程中淀粉代谢和质体超微结构研究h

Study on Changes of Plasmid Ultrastructure and Starch Metabolism during Fruit Development of Lycium barbarum L.

该研究以宁夏枸杞为材料,对其果实发育过程中果实淀粉含量、淀粉代谢相关酶活性进行测定,并对果实发育过程中果皮细胞内质体超微结构和淀粉组织化学定位进行了系统观察。结果表明:(1)枸杞果实内淀粉含量随果实的发育呈现先增加后降低的变化趋势,在果实花后14d其含量达到最高(13.85mg·g-1)。(2)果实内α淀粉酶活性和β淀粉酶活性随果实发育成熟呈现逐渐增加的趋势,且α淀粉酶活性始终明显高于β淀粉酶活性。(3)组织化学和超微结构研究表明,在果实转色(花后24d)以前果实的造粉体内有大量淀粉粒的存在,但在果实第二次快速生长期,果实内的淀粉粒分解、消失,而叶绿体内没有观察到淀粉粒。研究认为,淀粉是宁夏枸杞果实发育过程中碳水化合物的一种暂时贮存形式,对维持果实早期的库强起到了重要作用,但随着第二次快速生长期果实库强的增加,淀粉体内的淀粉被淀粉酶分解转化为还原糖贮藏在果肉细胞中。

In the development process of the fruit of Lycium barbarum L.,we measured the starch content and starch metabolism related enzyme activities in the fruit,and observed plasmid ultrastructure and starch histochemical localization in the peel cells systematically.The results showed that：（1）Starch content in the fruit of L.barbarum L.increased first and then reduced with the development of fruit,14 d after flowering its content reached the highest（13.85 mg · g^-1）.（2）In the fruit,α amylase activity and β amylase activity along with the fruit mature,presents the tendency of increase gradually,and α amylase activity is always higher than β amylase activity.（3）Histochemistry and ultrastructure studies have shown that the amyloplast enriched much more starch grain before veraison stage（24 days after blossom）,but starch grain almost disappeared during the second rapid growth stage,meanwhile the starch grain was not observed in chloroplast.The starch was a transient form of carbohydrate accumulation during fruit development,which was available to form sugar concentration gradient between ＂source＂ and ＂sink＂ and accelerate sugar unloading from phloem and played an important role in maintain the sink capacity in early phase fruit.With the sink capacity increasing during the second rapid growth stage,the starch was degraded into reducing sugars by the action of amylase and accumulated in fruit parenchyma cell.