不同耐密性玉米品种光合特性对弱光响应的差异

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。

Responses of Photosynthesis Characters to Low-light Stress for Maize Hybrids with Different Density Tolerances

Effects of low light stress treatments on the photosynthetic characteristics and changes in chlorophyll fluorescence parameters of two maize hybrids(ZD958,high-density-tolerance and DD90,low-density-tolerance) were evaluated to provide some theoretical basis for introducing,screening and cultivating of high-yield maize.The results showed that the net photosynthetic rate(Pn) of ZD958 was higher than DD90 under the full sunlight treatment.The apparent quantum yield(AQY),maximin photosynthetic rate(P_max),light saturation point(LSP) and light compensation point(LCP) of ZD958 were decreased under low light stress.However,DD90 only decreased in AQY,other parameters P_max,LSP,LCP was higher than under full sunlight treatment.It indicated that there was different protection mechanism for two maize hybrids.The perform of ZD958 was accorded with previous research,non-stomatal factors was the main reasons for the decrease of Pn.The improvement of photosynthetic capacity for DD90 was through reducing the heat dissipation of photosynthetic process.