磷素对小麦籽粒支链淀粉合成及其链长分布的影响

Effect of Phosphorus on the Biosynthesis and Chain-Length Distribution of Amylopectin in Wheat

为探究不同磷水平对小麦籽粒支链淀粉合成与支链淀粉精细结构的影响。以新冬20号(南疆主栽)和新冬23号(北疆强筋面包小麦)为材料,研究了3种施磷(P2O5)量0kg·hm-2(CK)、105kg·hm-2(CP)和210kg·hm-2(HP)对小麦籽粒支链淀粉合成相关酶基因表达、相关酶活性、籽粒支链淀粉含量、支链淀粉链长分布以及籽粒全磷含量的影响。结果表明,施磷显著提高了支链淀粉合成相关酶基因(sbe1、sbe2a、sbe2b、iso1)的表达量和籽粒支链淀粉含量。CP处理提高了支链淀粉B链段的比例,但降低了A链段的比例。两个参试小麦品种籽粒中支链淀粉合成关键酶的活性对磷素的敏感性不同,新冬20号受磷水平影响较大。施磷提高了新冬20号胚乳中蔗糖合成酶(SS)活性和酶活高峰期的淀粉分支酶(SBE)活性,提前了新冬20号胚乳中淀粉去分支酶(DBE)活性峰值的出现时间。

This study was conducted to investigate the effect of phosphorus on the biosynthesis and chain-length distribution of amylopectin in wheat. The Xindong 20 （winter wheat in Southern Xin- jiang） and Xindong 23（strong gluten bread winter wheat in Northern Xinjiang） were used to explore the effect of different phosphorus treatments, i. e. , 0 kg· hm-2 （CK）, 105 kg · hm-2 （CP） and 210 kg · hm-2 （HP）, on amylopectin development. The results showed that phosphorus application significantly increased the relative expression of genes involved in amylopectin synthesis （she1, sbe2a, she2b, isol ）, as well as increased the amylopectin content. The ratio of B-chain in amylopectin was increased under the CP treatment, but the ratio of A-chain was decreased. Changes of key enzyme activity related to amylopectin synthesis induced by phosphorus application were different within wheat variety. Enzymes of Xindong 20 were more susceptive to phosphorus application than those of Xindong 23. In response to phosphorus application, the activity of SS and peak activity of SBE was significantly increased and the peak activity of DBE was ahead in endosperm of Xindong 20.