甜菜氮糖代谢酶活力与蔗糖代谢的关系

初步探讨了甜菜生育期间叶片和根体中氮糖代谢关键酶 NR、GS、Ru SPase、SS活力的协调关系以及蔗糖的积累转化。结果表明 (1)氮糖代谢酶活力及其相关性主要在叶丛形成期和块根增长期达到显著 ,这两个时期是通过氮素协调氮代谢酶活力 ,实现以正常氮代谢促进蔗糖积累和转化的关键时期。 (2 )在叶丛形成期 ,随施氮量增加 ,NR、 GS、 Ru BPase和 SS分解方向活力提高 ,蔗糖和单糖含量下降 ;生育中后期 ,随施氮量增加 ,NR和 SS分解方向活力增强 ,GS和 SS合成方向活力减弱 ,蔗糖含量下降 ,单糖含量上升 ,总糖量降低。 (3)氮素对糖分含量的影响是通过氮素对氮糖代谢谢酶之间的协调作用的结果。根体中 GS与 SS活力的矛盾贯穿整个生育期 ,GS对 SS催化方向的改变可能起很关键的作用。

Relationship between activities of nitrogen and sucrose metabolism enzymes and sucrose metabolism in sugar beet (Beta vulgaris L.)

The studies on Nitrate Reductase (NR),Glutamine Synthetase(GS),RuBPase and Sucrose Synthetase(SS) activities and sucrose metabolism products content changes were conducted in root and leaf blade of sugar beet.The results were as follows:(1)The key stage of nitrogen and sucrose metabolism enzymes correlation was:NRA?GSA and RuBPase in leafblades correlated mainly at the early middle stage of the whole growth stage;GSA and SSA in root correlated mainly at foliage rapid growth stage (June 26) and root rapid growth stage(August 4).So the two stages were very important in controlling nitrogen and sucrose metabolism through nitrogen level applied (2)Sucrose metabolism products contents changed regularly and were influenced by nitrogen level applied.In the early middle growth stage,especially at foliage rapid growth stage,with increasing nitrogen level applied,NRA?GSA?RuBPase and SS synthesis activity showed negative correlation with the two nitrogen metabolism products.With increasing nitrogen level applied,NR?SS decomposition activity increased,and GS and SS synthesis activity declined.Thus sucrose content declined and monose content increased.(3)Influence of nitrogen levels on sucrose contents is the result of interaction between nitrogen and sucrose metabolism enzymes.Interaction between GS and SS happens through the whole stages of sugar beet,and GS may plays an important role in changing the direction of SS reaction.$$