淀粉含量不同木薯品种内源IAA与淀粉合成关键酶活性

以低淀粉木薯品种华南124及高淀粉品种辐选01为材料,研究木薯各生育时期叶片、茎秆和块根的内源IAA含量,块根淀粉合成关键酶ADPGpase、SSS和SBE活性,以及块根淀粉含量的变化。结果表明:1)木薯茎叶内源IAA含量与块根ADPGpase、SSS和SBE活性呈负相关,木薯生育后期高淀粉品种茎叶内源IAA含量逐渐下降,低淀粉品种则逐渐上升;2)块根内源IAA含量与块根ADPGpase、SSS和SBE活性呈显著正相关,生育后期高淀粉品种块根内源IAA含量显著大于低淀粉品种;3)块根ADPGpase、SSS和SBE活性与块根淀粉含量呈极显著正相关,生育后期高淀粉品种块根ADPGpase、SSS和SBE活性均显著高于低淀粉品种。可见,提高块根内源IAA含量有利于增加木薯块根淀粉合成关键酶活性,从而有效促进木薯块根淀粉的积累。

Endogenous IAA and the activities of starch synthesis key enzymes in cassava varieties with different starch content

Two cassava varieties,low-starch content variety SC124 and high-starch content variety RS01,were used as different genotype models according to their significant difference in root tuber starch content.The IAA contents in leaf,stem and root tuber,the activities of starch synthesis enzymes ADPGpase,SSS and SBE,and the starch content of root tuber at different growth stages were analyzed.The results showed that:1) There were negative correlations between the contents of IAA in stem and leaf and the activities of ADPGpase,SSS and SBE in root tuber.The contents of IAA in stem and leaf of RS01 at late growth stage were declined while the contents of IAA in SC124 were increased;2) There were significant positive correlations between the IAA content of root tuber and the activities of ADPGpase,SSS and SBE in root tuber.The IAA content within the root tuber of RS01 was higher than the content of root tuber in SC124 at the late growth stage;3) There were highly significant positive correlations between the starch content and the activities of ADPGpase,SSS and SBE within the root tuber and their activities in RS01 were higher than SC124 at the late growth stage.In conclusion,the IAA content within root tuber could cause positive effect on the activities of starch synthesis key enzymes which can accelerate the starch accumulation rate of cassava root tuber.