甜质型与普通型玉米籽粒发育过程中糖代谢相关酶活性的比较

Comparison of Enzymes Activity Associated with Sucrose Metabolism in the Developing Grains Between Sweet Corn and Normal Corn

对甜质型(ZeamaysL.SeccharataSturt)和普通型玉米(ZeamaysL.IndentataSturt)籽粒发育过程中蔗糖代谢和淀粉合成相关酶活性的变化动态进行了比较研究。结果表明,甜质型玉米籽粒发育过程中,蔗糖合成酶(SS)(包括合成与降解两个方向)和酸性蔗糖转化酶(Invertase)活性高于普通型玉米。甜质型玉米籽粒腺苷二磷酸葡萄糖焦磷酸化酶(ADPG-PPase)、尿苷二磷酸葡萄糖焦磷酸化酶(UDPG-PPase)、可溶性淀粉合成酶(SSS)活性高于普通型玉米,而束缚态淀粉合成酶(GBSS)、淀粉分支酶(SBE)和淀粉脱分支酶(SDE)活性低于普通型玉米,甜质型玉米SDE活性低是大量积累水溶性多糖(WSP)的直接原因,总淀粉积累量少和直链淀粉比例小是GBSS、SBE、SDE综合作用的结果。

Field experiments were carried out to compare the dynamic variations of enzymes activities of sucrose and starch metabolism in the developing grains of sweet corn (Zea mays L. Seccharata Sturt) and normal corn (Zea mays L. Indentata Sturt). The activities of SS (syntheses and degradation direction) and invertase in grains of sweet corn were higher than those of normal corn, so the increase of sucrose in sweet corn is resulted from the increase of sucrose synthetic ability, but not the reduction of sucrose degradation. The activities of ADPG-PPase, UDPG-PPase and SSS were higher in sweet corn than normal corn, but that of the SSS, SBE, SDE were lower than normal corn. The reductions of SDE activity lead to the accumulation of WSP. The decreases of total starch and amylose percent in total starch were resulted from the reduction of GBSS, SBE and SDE activities.