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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Fm,Fv,Fv/Fo和Fv/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。
The effects of exogenous Cd on photosynthetic characteristics of maize seedlings under simulated light conditions were studied. The results showed that under Cd stress, the maximum photosynthetic rate and leaf transpiration rate of maize decreased significantly, while the light saturation point and apparent quantum yield decreased. Under Cd stress, the stomatal conductance of maize leaves decreased. Under low light intensity, Cd stress played an important role in stomatal limitation. However, the reason for the lower photosynthetic rate under high Cd stress was non-stomatal factor. Stomatal conductance is more affected by Cd. Under Cd stress, the initial fluorescence Fo of dark-adapted maize leaves increased. The Fm, Fv, Fv / Fo and Fv / Fm decreased in both maize cultivars, indicating that the potential activity of PSII and the primary light energy conversion efficiency were weakened under Cd stress Cd stress had greater influence on the light energy conversion efficiency and electron transfer efficiency of Jitian 6.