摘要
通过对阜康典型荒漠C3 植物稳定碳同位素值的分析。叶片碳同位素值在 - 2 3‰和 - 2 9‰之间变化 ,其中主要在 - 2 7‰附近波动。这与前人报道的世界上其他地区荒漠植物碳同位素值的变化非常一致。降水可以改变叶片碳同位素值的大小 ,降水越多 ,叶片碳同位素值越负 ,它们的变化幅度有物种的依赖性。叶片碳同位素值也受植物生长形式或期望寿命的影响 ,木本植物或寿命长的植物叶片碳同位素值要高。分析表明 ,利用该区土壤或陆相沉积中有机质碳同位素值可以判断气候的干湿变化 :土壤或陆相沉积中有机质碳同位素值越高 。
Water is usually considered to be the key limiting factor for growth of desert plants, the positive relationship between the primary productivity and rainfall is generally observed. Research in recent years has demonstrated that carbon isotope values in C 3 plants can be used as an integrated indicator of relative water use efficiency. Absolute water efficiency in desert plants is influenced during the growing season by changes in water availability and leaf to air water vapor gradient, and thus changes significantly between seasons. These changes affect all plant species in a community, however, and therefore the relative ranking of carbon isotope values among species provides insight into fitness components related to water use efficiency since the relative ranking of carbon isotope values among plants grown under common conditions remain constant over time. On the other hand, vegetation is sensitive to the environmental change. Under the different environmental and climatic conditions, the vegetation is different even in the same area. After died, the plant body decomposed and its residual entered into soil, which is the main source of the organic matter in soil. So, the past climatic change and the vegetation condition could be uncovered by the variation of the carbon isotope values of organic matter in soil. In the present papers, leaf carbon isotope values were measured on species occurring within a desert community at Fukang County, Xinjiang. Leaf carbon isotope values ranged from -23.15‰ to -29.95‰, averaging -27.61‰, which was broadly comparable with values reported for other desert plants in the world. Less rainfall led to higher leaf carbon isotope values, but the magnitude of the isotope value changes depended on the species. A pattern of increasing leaf carbon isotope values with greater longevity was present. The analysis showed that the change of aridity and humidity could be disclosed by studying the carbon isotope values of soil and land sediments.
出处
《干旱区地理》
CSCD
北大核心
2002年第4期342-345,共4页
Arid Land Geography
基金
"引进国外杰出人才"项目 (中科院人教字 (2 0 0 2 ) 43号 )
中国科学院西部行动计划项目 (CX1-10 -0 6)
中国科学院冰芯与寒区环境开放实验室创新项目 (2 10 5 0 6)
中国科学院阜康荒漠生态系统试验站基金资助
