Grazing alters warming effects on leaf photosynthesis and respiration in Gentiana straminea,an alpine forb species  

作　　者：Haihua Shen Shiping Wang Yanhong Tang 

机构地区：[1]Center for Environmental Biology and Ecosystem Studies,National Institute for Environmental Studies,Onogawa 16-2,Tsukuba,Ibaraki 305-8506,Japan [2]State Key Laboratory of Vegetation and Environmental Change,Institute of Botany,Chinese Academy of Sciences,Beijing 100093,China [3]Institute of Tibetan Plateau Research,Chinese Academy of Sciences,Beijing 100085,China

出　　处：《Journal of Plant Ecology》2013年第5期418-427,共10页植物生态学报（英文版）

基　　金：National Natural Science Foundation of China(31000177);Sumitomo Foundation of Japan,a strategic Japanese-Chinese Cooperative Program on‘Climate Change’:Integrated assessment and prediction of carbon dynamics in relation to climate changes in grasslands on the Qinghai-Tibetan and Mongolian Plateaus,and the National Basic Research Program(2010CB833502).

摘　　要：Aims Vast grasslands on the Tibetan Plateau are almost all under livestock grazing.It is unclear,however,what is the role that the grazing will play in carbon cycle of the grassland under future climate warming.We found in our previous study that experimental warming can shift the optimum temperature of saturated photosynthetic rate into higher temperature in alpine plants.In this study,we proposed and tested the hypothesis that livestock grazing would alter the warming effect on photosynthetic and respiration through changing physical environments of grassland plants.Methods Experimental warming was carried by using an infrared heating system to increase the air temperature by 1.2 and 1.7℃ during the day and night,respectively.The warming and ambient temperature treatments were crossed over to the two grazing treatments,grazing and un-grazed treatments,respectively.To assess the effects of grazing and warming,we examined photosynthesis,dark respiration,maximum rates of the photosynthetic electron transport(J_(max)),RuBP carboxylation(V_(cmax))and temperature sensitivity of respiration Q_(10) in Gentiana straminea,an alpine species widely distributed on the Tibetan grassland.Leaf morphological and chemical properties were also examined to understand the physiological responses.Important findings 1)Light-saturated photosynthetic rate(A_(max))of G.straminea showed similar temperature optimum at around 16℃ in plants from all experimental conditions.Experimental warming increased A_(max) at all measuring temperatures from 10 to 25℃,but the positive effect of the warming occurred only in plants grown under the un-grazed conditions.Under the same measuring temperature,A_(max) was significantly higher in plants from the grazed than the un-grazed condition.2)There was significant crossing effect of warming and grazing on the temperature sensitivity(Q_(10))of leaf dark respiration.Under the un-grazed condition,plants from the warming treatment showed lower respiration rate but similar Q_(10) in comparison with plant

关 键 词：alpine plant GRAZING PHOTOSYNTHESIS RESPIRATION temperature acclimation 

分 类 号：S81[农业科学—畜牧学]