摘要：

为明确灌浆期高温胁迫对不同耐热型夏玉米品种叶片衰老及产量的影响,以高温敏感型品种先玉335和耐高温型品种郑单958为供试材料,于2019-2020年进行田间试验,在玉米吐丝后12~25 d搭设简易塑料增温棚进行高温胁迫处理,对照为田间自然温度处理,研究灌浆期高温对玉米叶片衰老与产量的影响。2 a结果表明,吐丝后12~25 d高温胁迫显著降低了夏玉米千粒质量和产量,其中高温处理下郑单958产量较对照降低18.8%,19.3%,千粒质量较对照降低23.4%,9.1%;高温处理下先玉335产量较对照降低29.4%,26.3%,千粒质量较对照降低20.1%,14.2%。灌浆期高温促进叶片衰老,2 a结果表明,郑单958叶片衰老速率在高温处理下显著增加76.4%,140.6%,先玉335增加135.1%,139.6%。高温处理下两品种的花后光合势较对照降低17.7%~36.5%,穗位叶光合速率降低20.0%~42.9%。相关分析结果表明,高温处理显著增加了夏玉米的叶片衰老速率,与产量呈负相关但不显著(P= 0.064 7);花后光合势、光合速率、SPAD值显著降低,与产量呈显著正相关(P< 0.05)。灌浆期高温胁迫显著加速玉米叶片衰老,导致玉米粒质量降低并减产,而耐高温型玉米品种比高温敏感型玉米品种具有更高的调节能力,能减轻高温胁迫导致的玉米减产。

关键词: 夏玉米, 高温, 叶片衰老, 产量

Abstract:

In order to clarify the effects of high temperature stress during grain filling stage on leaf senescence and yield,a field experiment from 2019 to 2020 was conducted with employing heat-sensitive variety(XY335)and heat-resistant variety(ZD958). Simple plastic greenhouse was constructed for heat treatment(HT)during 12-25 days after silking,the natural temperature was set as control(CK). The two years results showed that from 12 to 25 days after silking,high temperature stress significantly reduced the grain weight and yield of summer maize. For ZD958,the grain yield of HT was reduced by 18.8% and 19.3% than CK and thousand kernels weight(TKW)was decreased by 23.4% and 9.1%,respectively.For XY335,the grain yield and TKW of HT were reduced by 29.4%,26.3% and 20.1%,14.2%,respectively.High temperature during grain-filling stage accelerated leaf senescence. The two years results showed that leaf senescence rate(LSR)of ZD958 and XY335 under HT were increased by 76.4%,140.6% and 135.1%,139.6%,respectively.Leaf area duration(LAD)after silking with HT was reduced by 17.7%-36.5% compared with CK. Ear leaf photosynthesis under HT was lowered by 20.0%-42.9% than CK.Correlation analysis results indicated that accelerated LSR under HT had negative correlation with grain yield but without statistical significance(P=0.064 7).LAD after silking,photosynthesis,and SPAD significantly reduced under HT,which showed significant positive correlation with grain yield(P< 0.05). Taken together,heats tress during grain filling significantly accelerated leaf senescence,thus lowering kernel weight and resulting in yield loss. Under high temperature stress,heat-resistant maize variety had higher regulation ability than high temperature-sensitive maize variety,which could significantly mitigate yield loss caused by high temperature stress.

Key words: Summer maize, High temperature, Leaf senescence, Yield