Photosynthetic Physiological Response of Foxtail Millet to Weak Light Stress at Jointing-stage
To explore the mechanism of photosynthetic physiology of foxtail millet yield reduction caused under weak light stress at jointing-stage,two foxtail millet varieties,Zhangzagu 5 and Jingu 21,were subjected to different shading intensity treatments (0％,30％,60％ and 85％) at the jointing-stage for 15 days.The response of photosynthetic pigment contents,photosynthetic rate,and chlorophyll fluorescence parameters in the leaf and yield of the foxtail millet were investigated.The results showed that the shading treatment reduced the photosynthetic pigment contents,net photosynthetic rate (Pn),transpiration rate (Tr),stomatal conductance (Gs),apparent photosynthetic electron transport rate (ETR),PS Ⅱ practical photochemical quantum yield (ΦPS Ⅱ),coefficient of photochemical quenching (qP),and quantum yield dissipated by non-regulatory energy of the blade (Y (NO)),ear length,ear weight,ear grain weight,and the yield of foxtail millet,but significantly improved intercellular CO2 concentration (Ci),and the quantum yield Y(NPQ) dissipated by regulatory energy.ETR,ΦPS Ⅱ,and the yield of Zhangzagu 5 significantly decreased upon 30％ shading,but those of Jingu 21 greatly changed when the shading exceeded 60％.In conclusion,under weaklight stress at the jointing stage,the declined photosynthetic pigment contents,weakened capacity of catching and utilizing light energy,decreased PSⅡ photochemical activity and declined photosynthetic rate cause the decreased yield of foxtail.Zhangzagu 5 is more sensitive to the low-light stress than Jingu 21.The results of this study point out a direction for enhancing the resistance to weak light to achieve stable production by improving the photosynthetic function of foxtail millet at jointing stage,and provide a basis for selective breeding of foxtail millet with weak light stress tolerance.
国家科技期刊平台
NSTL
万方数据
维普
