Foliar δ^(13)C and δ^(15)N values of C_3 plants in the Ethiopia Rift Valley and their environmental controls  

作　　者：LIU XiaoHong ZHAO LiangJu GASAW Menassie GAO DengYi QIN DaHe REN JiaWen 

机构地区：[1]Key Laboratory of Cryosphere and Environment, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou 730000, China [2]Laboratory of Watershed Hydrology and Ecology, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou 730000, China [3]Department of Biology, University of Addis Ababa, Addis Ababa, P. O. Box 62619, Ethiopia [4]Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China

出　　处：《Chinese Science Bulletin》2007年第9期1265-1273,共9页

基　　金：Supported by the Import-Talents Program of the Cold and Arid Regions Environ-mental and Engineering Research Institute (Grant No. 2005104);the National Natural Science Foundation of China (Grant No. 40501076);the Chinese Science Expedition (DEEP) of the China Association for Scientific Expedition, and Inter-national Partnership Project of Chinese Academy Sciences (Grant No. CXTD-Z2005-2)

摘　　要：The foliar C and N stable isotopic compositions(δ 13C and δ 15N) and the relationships between these compositions and environmental factors of C3 plants in the Ethiopia Rift Valley were investigated. There were three distribution patterns for foliar δ 13C with mean values of ?26.7‰±0.4‰,?29.7‰± 0.6‰,and ?26.9‰± 1.2‰ in cold-moist,temperate-moist,and arid-hot environments,respectively. The δ 15N values ranged from ?1.4‰± 1.7‰ to 14.3‰± 0.1‰,with higher values under arid-hot conditions and the lowest values in plants growing at higher altitudes under cold-moist conditions. A strong negative relationship between mean annual precipitation and δ 15N explained more than half of the observed variation in the δ 15N values(r2 = 0.54,P < 0.001);a modest positive relationship was also found between δ 15N and tem-perature(r2 = 0.32,P < 0.01). A weakly positive relationship existed between δ 13C and temperature,and changes in δ 13C values with precipitation and altitude followed quadratic curves. This suggests a shift in the effects of water and heat conditions caused by altitude on carbon isotopic discrimination.The foliar C and N stable isotopic compositions （δ^13C and δ^15N） and the relationships between these compositions and environmental factors of C3 plants in the Ethiopia Rift Valley were investigated. There were three distribution patterns for foliar δ^13C with mean values of -26.7‰±0.4‰, -29.7‰ ±0.6‰ , and -26.9‰± 1.2‰ in cold-moist, temperate-moist, and arid-hot environments, respectively. The δ^15N values ranged from -1.4‰ ±1.7‰ to 14.3‰ ± 0.1‰, with higher values under arid-hot conditions and the lowest values in plants growing at higher altitudes under cold-moist conditions. A strong negative relationship between mean annual precipitation and δ^15N explained more than half of the observed variation in the δ^15N values （r2= 0.54, P 〈 0.001）; a modest positive relationship was also found between δ^15N and temperature （r2 = 0.32, P 〈 0.01）. A weakly positive relationship existed between δ^13C and temperature, and changes in δ^13C values with precipitation and altitude followed quadratic curves. This suggests a shift in the effects of water and heat conditions caused by altitude on carbon isotopic discrimination.

关 键 词：埃塞俄比亚裂谷 C3植物 叶片 碳稳定同位素 氮稳定同位素 环境因素 

分 类 号：Q914.5[天文地球—古生物学与地层学]