花后高温对小麦籽粒淀粉合成及相关酶活性的影响

【目的】研究小麦花后高温对籽粒淀粉合成及相关酶活性的影响,为小麦耐高温品种的选育及响应逆境胁迫提供理论依据。【方法】以新疆春小麦主栽品种新春11号为材料,于花后5~8 d进行高温处理,测定籽粒各时期淀粉含量及相关酶活性。【结果】花后高温处理显著降低了小麦籽粒各时期总淀粉、直链淀粉和支链淀粉含量及其积累速率;总淀粉和支链淀粉的积累速率呈单峰曲线变化,而直链淀粉的积累速率则呈现先下降后逐渐上升最后回落的变化趋势。花后高温处理下小麦籽粒各时期蔗糖合成酶(SS)活性、可溶性淀粉合成酶(SSS)活性和淀粉分支酶(SBE)活性显著低于对照,而焦磷酸化酶(ADPGase)活性虽然在各时期均低于对照,但差异不显著。在灌浆中后期SS、SSS、SBE活性与总淀粉含量、支链淀粉含量显著相关。【结论】高温胁迫显著降低了小麦籽粒淀粉合成相关酶的活性,进一步影响到小麦籽粒淀粉的积累。在小麦生产过程中,做好高温防范尤为重要。

Effects of Post-Anthesis High Temperature Stress on Starch Synthesis and Activities of Related Enzymes in Wheat Grain

【Objective】 The purpose of this project aims to explore the effects of post-anthesis high temperature on starch synthesis and related enzyme activities in wheat grain and provide a theoretical basis for breeding wheat varieties with high temperature tolerance and response to adversity stress.【Method】Xinjiang main cultivar Xinchun 11 was used as the experimental material and the starch content and related enzyme activity in different grain stages were measured at 5-8 d after anthesis.【Result】Post-anthesis high temperature treatment significantly reduced the contents of total starch, amylose and amylopectin and their accumulation rate, and the accumulation rate of total starch and amylopectin showed a single peak curve, while the amylose accumulation rate showed a downward trend and a gradual increase and then a downward trend. The activities of sucrose synthase (SS), soluble starch synthase (SSS), and starch branching enzyme (SBE) in wheat grain in different grain stages were significantly lower than those in the control by post-anthesis high temperature treatment but the difference was not significant. Correlation analysis showed that SS, SSS and SBE activities were significantly correlated with total starch content and amylopectin content during the late filling stage.【Conclusion】High temperature stress significantly reduced the activity of enzymes related to starch synthesis in wheat grain and further affected the starch accumulation in wheat grain. Therefore, in the process of wheat production, it is particularly important to take precautions against high temperatures.