氮磷添加对唐古特白刺叶绿素含量和光合活性的影响

本文采用叶绿素荧光成像和叶绿素荧光动力学相结合的方法研究外源氮（nitrogen，N）、磷（phosphorus，P）对荒漠植物唐古特白刺（Nitraria tangutorum）叶绿素含量、叶绿素荧光参数、荧光比R_fd的影响。结果表明：在添加P为3 gP·m^-2下，添加N为5 gN·m^-2，10 gN·m^-2和15 gN·m^-2时白刺的叶绿素含量显著下降（P < 0.05）；随着P的添加，叶绿素含量呈先增加后减小趋势，P3时（3 gN·m^-2+6 gP·m^-2）最大；外源N、P对白刺的F_m，F_v，F_v/F_m和R_fd的影响不显著，说明外源N、P未损害PSⅡ反应中心；单施P时，白刺的R_fd最大，荧光强度最强，而P3时的光化学效率较好，叶柄以上至中部的荧光较强。因此，本研究得出外源N、P对白刺叶绿素含量和荧光活性的影响具有耦合效应，N添加为3 gN·m^-2下配施6 gP·m^-2能够改善白刺的叶绿素含量和荧光活性；叶绿素荧光成像技术可直观地看出白刺的叶绿素荧光分布特征，为及时发现荒漠植物的胁迫症状提供了方法。

Effects of Nitrogen and Phosphorus Addition on Chlorophyll Content and Photosynthetic Activity of Nitraria tangutorum

In this study,we used the method of chlorophyll fluorescence imaging and chlorophyll fluorescence dynamics to explore the effects of exogenous nitrogen and phosphorus addition on chlorophyll content,chlorophyll fluorescence parameters and fluorescence ratio R_fd images of the typical desert plant,Nitraria tangutorum. The results showed that the chlorophyll content in the leaves of N. tangutorum decreased significantly (P<0.05) when 5,10 and 15 g N·m^-2 nitrogen combined with 3 gP·m^-2phosphorus were added. With the increase of phosphorus addition,the chlorophyll content in the leaves of N. tangutorum trended to increase first and then decrease,the maximum chlorophyll content reached when 6 g P·m^-2 phosphorus were provided. There was no difference among F_m,F_v,F_v/F_m and R_fd gradients (P>0.05),and exogenous nitrogen and phosphorus did not damage the reaction center of PSⅡ. In addition,The CFI technology showed when 3 g P·m^-2 was added,the fluorescence ratio R_fd of N. tangutorum was the largest and the fluorescence intensity was the strongest,and the fluorescence was stronger in the middle and upper part of the leaves. Under fixed nitrogen level,the P3 had better photochemical efficiency,and the fluorescence intensity from above petiole to middle part was stronger. Therefore,it was concluded that exogenous nitrogen and phosphorus addition have coupling effect on chlorophyll content and fluorescence activity of N. tangutorum,and 3 g N·m^-2 nitrogen with 6 g P·m^-2 phosphorus can improve the chlorophyll content and fluorescence activity. By means of CFI technology,we can directly see the distribution characteristics of chlorophyll fluorescence on the leaves of N. tangutica. It provides a method for finding the stress symptoms of desert plants in time.