灌浆结实期高温胁迫对糯玉米子粒产量和叶片光合特性的影响

以苏玉糯5号和渝糯7号为材料，研究灌浆结实期高温胁迫对子粒充实、叶片光合特性和产量的影响。结果表明，高温胁迫下灌浆后期粒重增速缓慢，穗粒数减少，产量降低。高温胁迫使花后5 d光合速率下降，胞间CO₂浓度、气孔导度和蒸腾速率上升。随灌浆进程推进光合参数逐渐降低，高温胁迫处理下降幅较高，是粒重降低并造成产量损失的关键因素。与苏玉糯5号相比，渝糯7号在高温胁迫处理下光合参数降幅较低，光合速率和胞间CO₂浓度中后期较高，受高温胁迫影响较小。

Effects of Heat Stress During Grain Filling on Grain Yield and Leaf Photosynthetic Properties of Waxy Maize

Using Suyunuo5 and Yunuo7 as materials, the effects of heat stress after pollination on grain filling, leaf photosynthetic properties and yield of waxy maize were studied. The results indicated that heat stress during grain filling slowing the grain filling rate after 22 days after pollination(DAP), in addition of decreased grain numbers, leading to the reduction of grain yield. The higher temperature at early stage(5 DAP) decreased the Pn and increased the Ci, Gs and Tr. With the proceeding of grain development, the photosynthetic characteristics gradually decreased and the decrement was more severe for plants exposed to a higher temperature. The large reduction of leaf photosynthetic capacities were the main reason resulting in the reduction of grain weight and loss of grain yield. The effects of heat stress on yield and photosynthetic parameter in Yunuo7 were less than in Suyunuo5 maybe due to its lower decrement of photosynthetic parameters under heat stress treatment and the higher Pn and Ci from 20 DAP to 35 DAP.