小麦淀粉合成关键酶活性及其与淀粉积累的关系

对小麦籽粒中淀粉及其组分积累动态、相关酶活性变化的研究结果表明2个供试品种淀粉及其组分积累量随灌浆的进行均呈不断上升的趋势,积累速率变化均呈单峰曲线,直链淀粉、支链淀粉、总淀粉积累速率峰值均出现在花后21～28 d.2个品种小麦花后籽粒中腺苷二磷酸葡萄糖(ADPG)焦磷酸化酶(AGPP)、游离态淀粉合成酶(SSS)、束缚态淀粉合成酶(GBSS)活性均呈单峰曲线变化,花后28 d前呈上升趋势,28 d达到峰值后开始下降.AGPP活性与SSS、GBSS活性呈极显著正相关.AGPP、SSS、GBSS活性与直链淀粉、支链淀粉、总淀粉积累速率、籽粒灌浆速率均呈极显著正相关.淀粉分支酶活性变化呈三次曲线的关系,前期活性较高,支链淀粉合成能力强,后期逐渐下降.

RELATIONSHIP BETWEEN ACTIVITIES OF KEY ENZYMES INVOLVING IN STARCH SYNTHESIS AND STARCH ACCUMULATION IN WHEAT

Time-course of starch and its component, and relevant enzyme activities in grains of two wheat varieties (Yangmai 12 and Xuzhou 26) were studied. Accumulating amount of starch and its components in grains of two varieties rose constantly after anthesis. The changes of accumulating rates showed a single peak curve. Amylose, amylopectin and starch accumulating rates reached their peaks on 28th-35th day after anthesis (DAA), respectively. AGPP, SSS and GBSS activities increased before 28th DAA on which they reached their peaks and began to drop. AGPP activity was significantly positively correlated with SSS and GBSS activities. AGPP, SSS and GBSS activities were significantly and positively correlated with amylose, amylopectin, starch accumulating rates and grain filling rate. Q enzyme activity could be simulated with cubic equation. Grain with higher Q enzyme activity at early stage had greater amylopectin synthesis ability, which dropped gradually at late stage.