Grazing every month minimizes size but boosts photosynthesis in Stipa grandis in the steppe of Inner Mongolia, China  

作　　者：LI Xiaobing HUANG Qi MI Xue BAI Yunxiao ZHANG Meng LI Xu 

机构地区：[1]State Key Laboratory of Earth Surface Processes and Resource Ecology, College of Resources Science and Technology, Beijing Normal University

出　　处：《Journal of Arid Land》2018年第4期601-611,共11页干旱区科学（英文版）

基　　金：funded by the National Basic Research Program of China (2016YFC0500502);the National Key Basic Research Program of China (2014CB138803);the National Natural Science Foundation of China (31570451);the Program for Changjiang Scholars and Innovative Research Team in University (IRT_15R06)

摘　　要：In order to explore the effects of grazing frequency on functional traits and to test whether Slipa gandis has compensatory photosynthesis during the frequent grazing period, we investigated morphological traits, biomass allocation, photosynthetic traits, and chlorophyll fluorescence parameters of the species in Inner Mongolia, China. The grazing frequency treatments included fencing （To）, grazing in May and July （T1, i.e., two months per year） and grazing from May to September （T2, i.e., continuous five months per year）. Results indicate that T1 and T2 treatments did not affect individual biomass, but T2 treatment negatively affected individual size, i.e., plant height, stem length, and leaf length. Physiological traits of S. grandis were significantly affected by grazing, year, and their interaction. In July 2014 （i.e., dry environment and low relative humidity）, the photosynthetic rate, transpiration rate and water use efficiency were highest under T2 treatment, which was caused by the increase in stomatal conductance. However, in July 2015 （i.e.,In order to explore the effects of grazing frequency on functional traits and to test whether Slipa gandis has compensatory photosynthesis during the frequent grazing period, we investigated morphological traits, biomass allocation, photosynthetic traits, and chlorophyll fluorescence parameters of the species in Inner Mongolia, China. The grazing frequency treatments included fencing （To）, grazing in May and July （T1, i.e., two months per year） and grazing from May to September （T2, i.e., continuous five months per year）. Results indicate that T1 and T2 treatments did not affect individual biomass, but T2 treatment negatively affected individual size, i.e., plant height, stem length, and leaf length. Physiological traits of S. grandis were significantly affected by grazing, year, and their interaction. In July 2014 （i.e., dry environment and low relative humidity）, the photosynthetic rate, transpiration rate and water use efficiency were highest under T2 treatment, which was caused by the increase in stomatal conductance. However, in July 2015 （i.e.,

关 键 词：grazing frequency morphological traits gas exchange photochemical efficiency water use efficiency 

分 类 号：S812[农业科学—草业科学]