内蒙古温带草原羊草叶片功能特性与光合特征对外源氮输入的响应  

Effects of mineral fertilizer addition on leaf functional traits and photosynthetic characteristics of Leymus chinensis from a temperate grassland in Inner Mongolia in China

作　　者：肖胜生[1,2] 董云社[1] 齐玉春[1] 彭琴[1,2] 何亚婷[1,2] 刘欣超[1,2] 

机构地区：[1]中国科学院地理科学与资源研究所,北京100101 [2]中国科学院研究生院,北京100049

出　　处：《环境科学学报》2010年第12期2535-2543,共9页Acta Scientiae Circumstantiae

基　　金：国家自然科学基金重点项目(No.40730105);国家自然科学基金面上基金(No.40973057);国家科技攻关计划(No.2007BAC03A11-02)~~

摘　　要：以内蒙古锡林河流域羊草草原典型植被羊草(Leymus chinensis)为研究对象,探讨了4个不同氮素输入水平(0、5、10和20g·m-·2a-1)下羊草叶片功能特性与光合特征的响应,并分析了外源氮输入背景下草地生态系统固碳潜势的变化.结果表明:中等水平施氮(10g·m-·2a-1)显著增加了羊草叶面积、叶绿素相对含量、叶氮浓度与净光合速率,但与中氮相比,高氮(20g·m-·2a-1)输入下却有所下降;施氮不仅对叶片净光合速率有一定程度的促进作用,而且延长了光合作用高峰期的持续时间;随着氮素添加梯度的增加,羊草叶片蒸腾速率降低,瞬时水分利用效率增高,气孔导度增大,胞间CO2浓度逐渐减小.从光合固碳的角度来看,适量的外源氮素输入有利于草地生态系统固定更多的CO2.This study explored the responses of leaf functional traits and photosynthetic characteristics of Leymus chinensis to different nitrogen（N） addition rates（0,5,10 and 20 g·m-·2a-1） in the Xilin River Basin in Inner Mongolia.In addition,the potential carbon sequestration of grassland plants exposed to increased N supply was estimated.The results showed that N addition（N-10 treatments） significantly increased the leaf area,relative chlorophyll content,leaf N concentration and net photosynthetic rates of L.chinensis.The N addition also extended the peak period of photosynthesis.With the increase of N addition rates,the transpiration rate,internal CO2 concentration gradually decreased,but instantaneous water-use efficiency and stomatal conductance increased gradually.The results indicated moderate N input would enhance CO2 sequestration through photosynthesis in semiarid temperate grassland.

关 键 词：羊草 氮输入 叶片功能特性 净光合速率 固碳 

分 类 号：X171.1[环境科学与工程—环境科学]