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以郑单958、东单90为试材,研究不同耐密性玉米品种光合特性对弱光胁迫响应的差异。结果表明,正常光照条件下郑单958光合性能优于东单90。郑单958在弱光胁迫后与其正常光照(对照)相比表观量子效率(AQY)增大,光合速率(Pn)、最大净光合速率(P max)、光补偿点(LCP)、光饱和点(LSP)均降低,表现出对弱光的光能利用效率明显高于对照,对强光利用效率较低。东单90在弱光胁迫后与其正常光照(对照)相比AQY降低,P max、LCP、LSP均升高,表现为对强光利用效率高,对弱光利用效率与对照基本相同。叶绿素荧光参数表明,郑单958弱光胁迫后PSⅡ光化学反应中心活性降低、高光强下光能利用效率降低主要是由于叶片光合活性下降;东单90弱光胁迫后对高光强的光利用效率升高的原因是叶片经弱光胁迫后减少了光合过程中的热耗散。
Taking Zhengdan 958 and Dongdan 90 as test materials, the differences of photosynthetic characteristics of low-light-stressed maize cultivars with different density were studied. The results showed that the photosynthetic capacity of Zhengdan 958 was better than that of Dongdan 90 under normal light conditions. Compared with the normal light (CK), Zhengdan958 had higher AQY, Pn, Pmax, LCP, Point (LSP) decreased, showing that the utilization efficiency of light energy of low light was significantly higher than that of the control, and the utilization efficiency of light was lower. Compared with the normal light (control), Dongdan 90 decreased AQY and P max, LCP and LSP increased under low light stress. The results showed that the utilization efficiency of high light and high light efficiency were the same as those of the control. The chlorophyll fluorescence parameters showed that the activity of PSⅡ photochemical reaction center decreased under low light stress, and the light utilization efficiency under high light intensity was mainly attributed to the decrease of photosynthetic activity of leaves. The reason why light utilization efficiency of high light intensity was increased after Dongdan 90 weak light stress It is the leaf that reduces the heat dissipation in the photosynthesis process after low light stress.