遮光对谷子光合性能及快速叶绿素荧光动力学特征的影响

Effects of Shading on Photosynthetic Characteristics and Rapid Chlorophyll Fluorescence Kinetic Characteristics of Foxtail Millet

为探讨弱光胁迫下谷子光合生理响应,以衡谷13号为材料,在幼苗期设置7种不同遮光处理(遮光0、10%、20%、30%、40%、50%、70%),在拔节期和灌浆期测定叶绿素含量、叶面积、净光合速率、产量和快速叶绿素荧光动力学参数的变化。结果表明,谷子叶绿素含量、叶面积、净光合速率、产量在遮光率高于20%时开始下降。荧光参数暗适应后初始荧光(Fo)、最大荧光(F_m)和可变荧光(F_v)在遮光后增大,PSⅡ反应中心最大光能转换率(F_v/F_m)、PSⅡ反应中心潜在活性(F_v/F_o)、光合性能指数(Pi_Abs)先随着遮光率的增大逐渐上升,遮光率为30%时达到最高,之后下降,遮光率为70%时低于对照。非光化学淬灭系数(NPQ_Lss)随着遮光程度的增大逐渐降低。

In order to investigate the photosynthetic physiological response of millet under low light stress,Henggu 13 was used as the experimental material,and 7 different shadings were set at the seedling stage(0,10%,20%,30%,40%,50%,70%).Chlorophyll content,leaf area,net photosynthetic rate,yield and rapid chlorophyll fluorescence kinetic parameters were determined at the jointing and filling stages.The results showed that chlorophyll content,leaf area,net photosynthetic rate and yield of millet began to decrease when shading rate was higher than 20%.Fluorescence parameters F_o,F_m and F_v increased after shading,F_v/F_m,F_v/F_o and Pi_Abs increased gradually with the increase of shading rate,and reached the highest at shading rate 30%,then decreased and was lower than the control at shading rate 70%.NPQ_Lss gradually decreases with the increase of shading degree.Millet can be planted in sparsely forested areas with low shading.