摘要： 研究了模拟光条件下,外源Cd胁迫对苗期玉米光合特性的影响。结果表明,Cd胁迫下导致玉米的最大光合速率和叶片蒸腾速率明显降低,光饱和点和表观量子产额有所下降。Cd胁迫下玉米叶片气孔导度减小,低光强时,Cd胁迫对气孔的限制起到较为重要的作用,而在高光强时Cd胁迫导致光合速率较低的原因为非气孔因素,吉甜6的气孔导度受Cd影响更大。Cd胁迫处理使暗适应的玉米叶片的初始荧光Fo升高;2个玉米品种的F_m,F_v,F_v/F_o和F_v/Fm均下降,表明Cd胁迫下PSII的潜在活性和原初光能转换效率减弱;Cd胁迫对吉甜6的光能转换效率和电子传递效率的影响更大。

关键词: 镉胁迫, 玉米, 光合, 荧光

Abstract: A pot experiment was conducted to study the effects of added cadmium(Cd)on photosynthetic characteris -tics of maize under simulated photosynthetic radiation(PAR). The results showed that under Cd stress, maximum photo -synthesis rate(Pnmax), transpiration rate(Tr)decreased significantly. Light saturation point(LSP)and apparent quantumyield(AQY)were also reduced. Cd stress decreased stomatal conductance(Gs).The reduction of Pnby Cd stress were dueto the stomatal limitation under lower PAR,while non -stomatal limitation under higher PAR. Gs of Jitian 6 was more af -fected by Cd stress.The initial fluorescence yield(F_o)of maize leaves with dark adaptation was increased. However themaximum fluorescence yield(F_m), the variable fluorescence(F_v), the potential activity of photosystem II(Fv/Fo), the max -imal quantum yield of photosystem II photochemistry(F_v/F_m)decreased due to Cd stress. It indicated that the efficiency ofprimary conversion of light energy of PS II and its potential activities were inhibited significantly caused by Cd stress.Comparing with Jidan 209, Jitian 6 suffered more reduction in efficiency of light energy transfer and electron transport.

Key words: Cd stress, Maize, Photosynthesis, Fluorescence

中图分类号: 

• S513.01