镉胁迫下铵态氮对春小麦光合生理特性的影响

为了研究铵态氮肥在缓解镉毒害对植物影响方面的作用,减少镉的危害,试验采用盆栽方法模拟镉污染农田,以辽春10号小麦Triticum aestivum为试材,无氮无镉的处理（H0）作为对照,设置5个铵态氮施用水平,即0（CH0）、75（CH1）、150（CH2）、225（CH3）和300（CH4）kg·hm-2,研究不同施氮量下铵态氮肥对小麦光合生理特性的影响。结果表明：与无氮无镉处理相比,无氮镉胁迫处理极显著地（P〈0.01）抑制了小麦叶片净光合速率（Pn）、叶片气孔导度（Gs）、胞间CO2体积分数（Ci）、蒸腾速率（Tr）和Hill反应活力,但对小麦叶绿素含量和叶绿体Ca2＋/Mg2＋-ATPase活性的抑制作用不显著（P〉0.05）;小麦叶片Gs,Ci和Tr随着施氮量增加逐渐升高,而小麦叶片Pn、叶绿素含量、Hill反应活力和叶绿体Ca2＋/Mg2＋-ATPase活性呈现先升高后降低的趋势,从净光合速率角度看,225 kg·hm-2施氮水平（CH3）氮的解毒作用最佳。

Effects of NH4+-N on photosynthetic characteristics of Spring wheat plant under cadmium

Pot experiment was conducted to study the effect of NH4＋-N in alleviating cadmium toxicity to crops with regard to reduce the harm of cadmium on human health.The experiment simulated farmland polluted by cadmium and involved five NH4＋-N levels（0、75、150、225、300 kg·hm-2）.The results indicated that the photosynthetic,stomatal conductance,intercellular CO2 concentration,transpiration rate and Hill activity was significance restrained（P0.01）compare to the control,but the content of chlorophyll and Ca2＋/Mg2＋-ATPase activity was restrained insignificantly（P0.05）.The Gs,Ci and Tr of wheat leaves was ascended with rising of NH4＋-N,but the Pn,content of chlorophyll,Hill activity and Ca2＋/Mg2＋-ATPase activity ascended first and declined following.To see from photosynthetic,225 kg.hm-2 nitrogen level is the best in alleviating cadmium toxicity.