选用小麦旱地品种长武134和水地品种陕253,研究土壤干旱对小麦籽粒淀粉积累及相关酶活性的影响,探讨土壤干旱影响淀粉积累的酶学机制.结果表明,干旱处理提高了灌浆前期小麦籽粒淀粉积累速率、籽粒SS、AGPase、UGPase、SSS和GBSS酶活性.灌浆后期旱地品种籽粒淀粉积累速率及AGPase、UGPase降低幅度大于水地品种,而SS降低幅度则小于水地品种;旱地品种灌浆后期SSS活性与对照无明显差异,而水地品种SSS活性则大于对照;与其它淀粉合成酶活性相比,干旱对灌浆后期GBSS活性影响程度较小.分析结果表明,SS、AGPase是干旱影响小麦淀粉积累速率的主要调节酶,抗旱性强的小麦品种AGPase的调节作用较大,而抗旱性弱的小麦品种SS的调节作用较大.%Two types of winter wheat ( Triticum aestivum. L), including dryland cultivar Changwu 134 and irrigated land cultivar Shaan 253, were selected to study the effects of soil drought on starch accumulation of grain and activity of corresponding starch synthesis enzymes, and then to elucidate some physiological mechanisms of wheat grain filling under soil drought condition. The results indicated that soil drought could significantly increase the starch accumulation rate and SS, AGPase, UGPase, SSS and GBSS activity of grains in two different varieties during the early filling stage. The extent of reduction in the grain starch accumulation rate and the activity of AGPase and UGPase of the dryland cultivar was significantly higher than that of the the irrigated cultivar, but the SS activity of dryland cultivar was significantly lower than that of irrigated cultivar during the late filling stage. The SSS activity of drought - treated grains'in dryland cultivar didn't have obvious changes, but significant increase occurred in irrigated cultivar as compared to control. Compared with other starch synthesis enzymes, the GBSS activity was affected slightly by soil drought treatment during the late filling stage.Analysis results indicated that SS and AGPase might be the key regulatory enzymes affecting grain starch accumulation rate, and AGPase played a main role for drought-resistant cultivar. But for the drought-sensitive cultivar, SS could be a determinant enzyme.
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