玉米灌浆期水分差异供应对籽粒淀粉积累及其酶活性的影响

EFFECTS OF DIFFERENT WATER TREATMENTS ON STARCH ACCUMULATION AND RELATED ENZYME ACTIVITY IN GRAIN OF MAIZE DURING GRAIN-FILLING PERIOD

利用普通玉米(Zaymays)‘掖单22'和高油玉米‘高油115',研究了灌浆期水分差异供应对籽粒淀粉及其组分积累、相关酶活性动态变化的影响.结果表明,两种类型玉米淀粉积累和酶活性动态变化趋势基本一致,但对水分的反应有差异.缺水提高了‘掖单22'籽粒中淀粉、支链淀粉含量,而直链淀粉含量下降,‘高油115'则是籽粒中的淀粉含量、支链淀粉和直链淀粉含量提高;充分供水使淀粉及其组分产量提高;叶片中蔗糖合成酶(SS)、磷酸蔗糖合成酶(SPS)活性随水分供应水平而提高,尤其在授粉后10～30 d增幅更加明显.充分供水明显提高籽粒中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)和淀粉粒结合淀粉合成酶(GBSS)活性,缺水使籽粒中酶活性下降较早且迅速;SPS、ADPG-PPase、SSS酶活性对缺水反应比较敏感.

Starch, one of the main products metabolized in the grain of maize, directly affects the yield and quality of maize. The synthesis of starch in maize grain is affected by the activities of several enzymes. We studied the effects of different water treatments on the grain starch content and components and related enzyme activity during the grain-filling period of two cultivars—the common corn, Yedan22, and the high oil corn, Gaoyou115. Three water treatments were chosen: W0 (no water irrigation after anthesis), W1 (irrigation one time after anthesis), W2 (irrigation two times after anthesis). The results showed that the patterns of starch accumulation and related enzyme activity were the same in the two cultivars, but their response to water treatments were different. Water duress significantly increased starch and amylopectin content and decreased amylose content in Yedan22, but increased the starch, amylopectin and amylose content in Gaoyou115. When sufficient levels of water were supplied, starch yield and its components significantly increased, as did the SS and SPS activities in ear leaves and ADPG-PPase, UDPG-PPase, SSS and GBSS activities in the grain, especially 10 to 30 days after anthesis. Increased enzyme activity in grain increased the amylopectin and amylose content in Gaoyou115. The activities of these enzymes in grain under water duress decreased early and quickly, and the activities of SPS, ADPG-PPase, and SSS were more sensitive to water duress than other enzymes.