花后干旱对小麦胚乳淀粉粒发育和理化特性的影响

Effect of Drought Post-anthesis on the Development and Physicochemical Characteristics of Starch Granule in Wheat

我国小麦主产区在籽粒灌浆期往往频发干旱,常导致小麦产量下降和品质变劣。为了解花后干旱对小麦籽粒淀粉粒发育及淀粉理化特性的影响,以中强筋小麦新冬20号和新冬23号为供试材料,在花后干旱胁迫下对小麦籽粒灌浆过程中淀粉粒形态、粒径、淀粉降解酶活性以及淀粉相对结晶度、持水力、膨胀势、溶解度和破损淀粉粒含量进行了研究。结果表明,花后干旱处理下两个参试小麦品种的淀粉粒基本形态未发生明显变化。对比新冬20号,花后干旱对新冬23号淀粉粒的形成、发育影响更大。花后干旱处理下,新冬20号和新冬23号胚乳中的淀粉降解酶活性均在灌浆后期达到峰值,花后35d时,籽粒淀粉降解酶活性均明显高于同时期的对照。花后干旱未改变参试小麦品种淀粉粒的结晶类型,但降低了其相对结晶度。花后干旱处理的新冬23号籽粒中淀粉粒的持水力和破损淀粉含量显著低于对照。试验说明花后干旱胁迫影响了小麦籽粒灌浆过程中淀粉降解酶活性,进而作用于淀粉粒的表观结构,最终对淀粉粒的理化特性产生影响,影响程度与参试小麦品种的遗传特性有关,干旱敏感型品种受其影响更为明显。

In China, drought stress is frequent during wheat grain filling period in main wheat production areas, which lead to yield reduction and quality deterioration of wheat. The effect of drought post-anthesis on the development and physicochemical characteristics of starch granule in winter wheat varieties of Xindong 20 and Xindong 23 was studied. The results showed that starch granules of two cultivars showed bimodal size distributions under different treatments and their basic form didn＇ t change. The changes of granule size induced by drought in Xindong 23 were more obvious than those in Xindong 20. The crystal type of starch granule of two wheat varieties did not change significantly under different treatments,but crystallinty decreased. The flour of Xindong 23 under drought condition showed significantly lower water-binding capacity and damaged starch content. Drought induced the enhancement of activities of s-Amylase and β-Amylase at late grain filling period, which might have an effect on surface micro-structures of starch granules. Moreover, the changes of surface microstructures of granules brought about by drought conditions might attributed to a change in physicochemical characteristics.