花后前期高温对玉米强弱势籽粒生长发育的影响

采用籽粒离体培养的方法,研究花后高温对玉米强、弱势籽粒的影响。结果表明,高温处理加快了强、弱势籽粒前期的灌浆速率,但降低了中后期的灌浆速率,导致粒重降低,且对弱势粒影响尤为显著,高温处理强、弱势粒成熟期粒重分别比对照低5.8%、17.4%;高温显著降低了籽粒不同灌浆时期的淀粉合成相关酶活性,从而使淀粉含量降低,强势粒的淀粉含量降低幅度小于弱势粒;与对照相比,高温处理后强势籽粒中的3-吲哚乙酸(IAA)和玉米素核苷(ZR)含量显著下降,赤霉素(GA3)含量则无显著差异,而弱势粒IAA、ZR含量显著降低,但GA3含量增加,可能是导致弱势粒干重受损较大的原因。

Effect of High Temperature after Flowering on Growth and Development of Superior and Inferior Maize Kernels

The kernel culture in vitro was adopted to study the effect of high temperature after flowering on maize superior and inferior kernels. Results indicated that dry matter accumulation of grain decreased, due to the fact that grain development was accelerated at early grain-filling stage by high temperature, but declined at middle late grain filling stage. In mature stage, the dry weight of superior and inferior kernels under high temperature was reduced by 5.8% and 17.4% respectively, so inferior kernels had a more reduction than superior kernels. The synthesis of starch was influenced by reducing the activity of enzymes related to starch synthesis significantly at different grain-filling stages under high temperature treatment. The contents of IAA, ZR in kernel were significantly reduced after being treated with high temperature. The content of GA₃ was increased in inferior kernels, but not in superior kernels. It could be deduced that the much dry weight loss of inferior kernels should be ascribed to the increasing in GA₃ content when kernels exposed to high temperature.