内蒙古温带草原大针茅叶片光合生理特性对氮添加的响应  

Response of the photosynthetic physiological characteristics to nitrogen addition of Stipa grandis leaves in a temperate grassland of the Inner Mongolia

作　　者：董姣姣 龚吉蕊[1,2] 翟占伟 张子荷 矢佳昱 张魏圆 宋靓苑 李颖 张斯琦[1,2] DONG Jiaojiao;GONG Jirui;ZHAI Zhanwei;ZHANG Zihe;SHI Jiayu;ZHANG Weiyuan;SONG Liangyuan;LI Ying;ZHANG Siqi(State Key Laboratory of Earth Surface Processes and Resource Ecology,Faculty of Geographical Science,Beijing Normal University,Beijing 100875,China;School of Natural Resources,Faculty of Geographical Science,Beijing Normal University,Beijing 100875,China)

机构地区：[1]北京师范大学地表过程与资源生态国家重点实验室,北京100875 [2]北京师范大学地理科学学部自然资源学院,北京100875

出　　处：《生态学报》2023年第14期5994-6004,共11页Acta Ecologica Sinica

基　　金：内蒙古自治区科技重大专项课题项目(2021ZD0011⁃04);国家自然科学基金面上项目(41571048)。

摘　　要：大气氮沉降增加生态系统氮有效性,优势种植物对不同水平氮输入的响应影响草原生态系统结构和功能。研究设置4个氮添加水平,分析内蒙古温带草原优势种大针茅(Stipa grandis)光合生理特性对不同梯度氮添加的响应。结果表明:低氮(0—2 g m^(-2)a^(-1))处理时,大针茅叶片氮含量较低,叶绿素含量和1,5⁃二磷酸核酮糖羧化/加氧酶的活性不高,光能利用效率低,导致光系统II出现过剩激发能,光合器官受到抑制,净光合速率相对较低。适量氮添加(5—10 g m^(-2)a^(-1))提高了大针茅叶片羧化系统和电子传递系统的氮分配,进而提高了1,5⁃二磷酸核酮糖羧化/加氧酶的活性以及电子传递速率,净光合速率增大。高氮(25 g m^(-2)a^(-1))处理时,叶片氮含量较高,但光合氮分配比例下降,降低了光合氮利用效率。大针茅光抑制程度增大,叶绿素含量、1,5⁃二磷酸核酮糖羧化/加氧酶的活性下降,不利于生物量积累。研究结果有助于进一步了解全球变化背景下草原生态系统优势种的生理响应机制,并为草原的可持续发展提供一定的理论依据。Atmospheric nitrogen deposition increases ecosystem nitrogen availability,and the response of dominant species to different levels of nitrogen input may change grassland ecosystem structure and function.In this study,four nitrogen addition levels were set to analyze the responses of the photosynthetic physiological characteristics of Stipa grandis,a dominant species of temperate grassland in the Inner Mongolia,to different levels of nitrogen addition.The results showed that the nitrogen content of Stipa grandis leaves was lower,chlorophyll content and the ribulose 1,5⁃diphosphate carboxylation/oxygenase activity were not high,and the low utilization efficiency of light energy led to excess excitation energy in photosystem II,photosynthetic organ was inhibited,resulting in a relatively low net photosynthetic rate under low nitrogen treatment(0—2 g m^(-2)a^(-1)).Moderate nitrogen addition(5—10 g m^(-2)a^(-1))improved the nitrogen allocation of leaf carboxylation system and electron transport system,which increased the activity of ribulose 1,5⁃diphosphate carboxylation/oxygenase and the electron transfer rate,thereby the net photosynthetic rate of Stipa grandis was increased.Under high nitrogen treatment(25 g m^(-2)a^(-1)),the nitrogen content in Stipa grandis leaves was higher,but the allocation ratio of photosynthetic nitrogen decreased,which reduced the utilization efficiency of photosynthetic nitrogen.Meanwhile,the degree of light inhibition of Stipa grandis was increased,chlorophyll content and the ribulose 1,5⁃diphosphate carboxylation/oxygenase activity decreased,which was not conducive to biomass accumulation.These results help to further understand the physiological response mechanism of dominant species in grassland ecosystems under the global change,and provide a certain theoretical basis for the sustainable development of grassland.

关 键 词：内蒙古温带草原 氮添加 光合作用 光合氮分配 碳代谢酶 

分 类 号：S812[农业科学—草业科学]