宁麦9号花后内源激素和蔗糖含量变化及其与籽粒淀粉合成的关系

为研究小麦花后旗叶和籽粒中内源激素、蔗糖含量及籽粒中淀粉积累的动态变化,以弱筋小麦宁麦9号为供试材料在两种施肥处理条件下分析了花后内源激素和蔗糖含量变化与籽粒淀粉合成的关系.结果表明,氮肥后移的处理旗叶中ZRs、iPAs含量的增加及ABA含量的减少,有利于光合产物的合成;蔗糖含量较高,为籽粒合成淀粉提供了充足的碳源物质.籽粒中淀粉及其组分积累量灌浆期呈不断上升的趋势,积累速率呈单峰曲线,直、支链淀粉和总淀粉积累速率峰值期均在花后21～28 d,氮肥后移表现为增加趋势.相关分析表明,籽粒中内源激素ABA与蔗糖含量呈极显著负相关,GA1/3/ABA与蔗糖含量呈极显著正相关,IAA、GA1/3与淀粉积累速率呈极显著正相关.通径分析表明,籽粒中内源激素IAA对淀粉积累速率有极显著促进作用,直接通径系数达0.9627**,GA1/3主要是通过提高IAA含量间接促进籽粒中淀粉的积累,说明适当提高IAA含量有利于促进籽粒淀粉的积累.

Relationship of Grain Starch Synthesis with Changes of Endogenous Hormone and Sucrose Content after Anthesis in Wheat Variety Ningmai 9

The relationship of grain starch synthesis with changes of endogenous hormone and sucrose contents after anthesis in wheat variety Ningmai 9 was studied at experimental field of Jiangsu provincial key lab of crop genetics and physiology from 2000~2002.The results indicated that the treatment of increasing top dressing N applying ratio could increase endogenous hormones zeatin riboside(ZRS),isopentenyl adenosine(iPAs) contents and decrease abscise acid(ABA) contents in flag leaves,and improve photosynthate synthesis,which could increase sucrose contents in flag leaves and supply aplenty of carbon sources for starch synthesis in grains.Accumulated amount of starch and its components in grains rose constantly after anthesis.The changes of accumulating rates showed a single-peak curve.Amylose,amylopectin and starch accumulating rates reached their peaks on 21st ~28th day after anthesis.ABA contents in grains were significantly and negatively correlated with sucrose contents in grains.The ratio of gibberellin(GA1/3) to ABA in grain was significantly and positively correlated with sucrose contents in grains.The accumulation rate of starch was highly correlated to indole-3-acetic(IAA) contents with the standardized estimate as high as 0.9627.GA1/3 contents in grains indirectly promote starch accumulating through improving IAA contents appropriately.Path coefficient analysis indicated that IAA content in the developing grains played a key role in promoting grain starch accumulation in wheat grains.