籽粒灌浆期高温对不同耐热型玉米品种强弱势粒发育的影响

【目的】灌浆期高温会对玉米籽粒的生长和发育造成不利的影响,是影响玉米稳产和高产的重要因素之一。比较灌浆期高温对不同耐热型玉米品种籽粒形成和生长发育的影响,以期寻找相应的预防和应对措施,避免和缓解高温胁迫伤害。【方法】采用玉米籽粒离体培养技术,以耐热型品种郑单958和热敏感型品种德美亚1号为材料,研究了籽粒灌浆期(授粉后17—28 d)高温对玉米籽粒发育的影响机制。【结果】高温加快了两品种玉米强势粒前期的灌浆速率,但降低了强、弱势粒中后期灌浆速率,总体导致灌浆持续时间缩短,籽粒千粒重下降。在授粉后40 d,郑单958强、弱势粒的干重分别比对照低10.58%和18.95%,德美亚1号强、弱势粒的干重分别比对照低24.78%和28.08%。德美亚1号籽粒干重下降幅度大于郑单958,且差异显著。籽粒灌浆期高温显著降低了玉米籽粒淀粉合成酶的活性,从而影响两品种玉米籽粒的淀粉含量。在授粉后40 d,郑单958强、弱势粒的淀粉含量较对照分别降低了5.20%和6.46%,德美亚1号强、弱势粒的淀粉含量较对照分别降低了13.68%和16.39%,均差异显著。德美亚1号强、弱势粒淀粉合酶的活性较对照分别降低了19.67%和30.03%,均差异显著,郑单958强、弱势粒的淀粉合成酶的活性分别较对照降低了13.70%和11.26%。高温处理后,两种品种玉米籽粒的ABA和IAA含量均上升,ZR含量均下降,而强势粒的GA3含量均上升,弱势粒的GA3含量无明显变化。【结论】籽粒灌浆期高温对德美亚1号强、弱势粒发育的影响均显著高于郑单958,对两品种弱势粒的影响显著高于强势粒。

Effects of High Temperature During Grain Filling Period on Superior and Inferior Kernels’ Development of Different Heat Sensitive Maize Varieties

【Objective】High temperature during grain filling period is likely to cause large negative impacts on maize kernel growth and development, which is one of the important factors affecting high and stable yield of maize. To avoid and relieve the damage of high temperature and to find out the effective methods, this study compared the effects of high temperature during grain filling period on kernel formation and development of maize varieties with contrasting heat sensitivities.【Method】The temperature non-sensitive variety (Zhengdan958) and temperature sensitive variety (Demeiya1) were used in vitro culture system to investigate the influence of high temperature on maize kernel development during grain filling period (17-28 days after pollination, DAP).【Result】High temperature accelerated grain filling rate at early stage for both varieties, but decelerated grain filling rate at late stage for both varieties. As a result, the duration was shortened for grain filling and thousand kernel weight was decreased. At 40 DAP, the dry weight of Zhengdan 958 superior and inferior kernels were reduced by 10.50% and 18.95%, the dry weight of Demaya 1 superior and inferior kernels were respectively reduced by 24.78% and 28.08%. Moreover, starch synthesis was influenced by reducing the activity starch synthase under high temperature. The degree of the reduction of Demaya 1 superior and inferior kernels is significantly higher than Zhengdan 958. At 40 DAP, the starch content of Zhengdan 958 superior and inferior kernels were respectively lower 5.20% and 6.46% than the controls, the starch content of Demeiya 1 superior and inferior kernels were lower 13.68% and 16.39% than the controls. The starch synthase activities of superior and inferior kernels of Demaya 1 were reduced by 19.67% and 30.03%, respectively. The starch synthase activity of Zhengdan 958 of superior and inferior kernels was reduced by 13.70% and 11.26%, respectively. The ABA and IAA content in maize kernels of both varieties with high temperature treatment increased significantly while the ZR content decreased, and the GA3 content in superior kernels of both varieties increased while the GA3 content in inferior kernels of both varieties didn’t change significantly.【Conclusion】It was found that the effects of high temperature during grain filling period were more serious on grain development of Demaya 1 than Zhengdan 958, and had more effects on the inferior kernels than superior kernels of both varieties.