【作者】 旺罗； 吕厚远； 吴乃琴； 吴海斌； 刘东生；

【Author】 Wang Luo L Houyuan Wu Naiqin Wu Haibin Liu Tungsheng (Institute of Geology and Geophysics.Chinese Academy of Sciences,Beijing 100029)

【机构】 中国科学院地质与地球物理研究所；

【摘要】 文章通过分析青藏高原4种C₃禾本科植物碳同位素值随海拔高度的变化,发现穗三毛（Trisetum spicatum）,垂穗鹅观草（Roegneria nutans）,紫花针茅（Stipa purpurea）,垂穗披碱草（Elymus nuttans）的碳同位素值随海拔高度增加而变重的趋势明显,平均每增高1km变重1.37‰,其中Trisetum spicatum和Roegneria nutans的碳同位素值随海拔高度增加而变重的趋势更为显著。研究认为温度和大气CO₂分压是引起C₃植物碳同位素值随海拔高度变化的主要因素。另外,研究发现一些C₄植物的生长高度可以达到海拔4 000m以上,最高可达海拔4 520m。更多还原

【Abstract】 In a global survey ofδ¹³C values of plants collected from a wide range of altitudes,spanning many taxonomic and physiognomic groups as well as a wide geographic range,C.Korner et al. found thatδ¹³C values increased with altitude.Other researchers found thatδ¹³C values in single species increase with altitude.However,Most of these studies were carried out on a very restricted range of sites.So far,relatively few systematic studies have addressed howδ¹³C values in single species growing in a complicated environment like Qinghai-Xizang Plateau change with altitude. In this survey stable carbon isotope compositions are determined on leaves of Poaceae plants （Trisetum spicatum,Roegneria nutans,Stipa purpurea,Elymus nutans） sampled along a 2 000km transect on Qinghai-Xizang Plateau of China.δ¹³C values for all samples increase with altitude generally,the meanδ¹³C increase with altitude is 1.37‰/km.Carbon isotope ratios of Trisetum spicatum and Roegneria nutans increase significantly with altitude.The result of linear analyses indicates that temperature and CO₂ partial pressure are the major factors causing theδ¹³C ratios of C₃ plants to increase with altitudes.In this study,we sampled C₄ plants:Chloris virgata,Eragrostis ferruginea,Eragrostis nigra,Arundinella yunnanensis,Orinus thoroldii,Pennisetum centrasiaticum, Atriplex centralasiatica,Salsola ruthenica and found some of them distributed above 4 000m,even reached 4 520m.更多还原