氮素添加对荒漠区两种濒危植物及其近缘种光合速率的影响

Effects of Addition of Nitrogen on Photosynthetic Rate of Two Endangered Plants and Their Related Species in Desert Area

以2.5 g N·m^(-2)的计量分2次叶面喷施处理,使氮素年添加量达到5.0 g N·m^(-2)·a^(-1),以探讨高通量氮沉降对荒漠区濒危植物沙冬青和蒙古扁桃及其近缘种光合速率的影响.实验结果表明:各植物光合速率日动态均呈"双峰"曲线型,干旱缺水使得午后峰值不明显;叶面喷施氮素处理组植物光合速率日平均值均低于对照组,表明干旱缺水环境下氮素添加不能有效提高植物光合速率.面对全球性的大气氮沉降危机,濒危植物作为环境敏感植物其生存遇到新的挑战.

To investigate the effects of high level nitrogen deposition on photosynthetic rate of endangered plants Prunus mongolica,Ammopiptanthus mongolicus and their related species in desert areas, 5.0 g N·m^-2 nitrogen was added to the plants by two times (2.5 g N·m^-2 per time) through spraying to foliage and the daily dynamic changes of photosynthetic rate were observed in this research.The experimental results gave an untypical “double peak” curve model which had a weak afternoon peak because of the water shortage of afternoon for the daily dynamic change of photosynthetic rate of all the plants.The great interesting was that the photosynthesis rate of the plants treated with high level nitrogen group was lower than that of the control group,indicating that nitrogen addition could not effectively increase the photosynthetic rate of plants under water shortage stress.Our experiment results suggest that with the heavy global nitrogen deposition in atmosphere,the survival of the endangered plants will be a serious problem.