祁连山两种优势乔木叶片δ^(13)C的海拔响应及其机理  

Responses of foliar δ^(13)C in Sabina przewalskii and Picea crassifolia to altitude and its mechanism in the Qilian Mountains,China

作　　者：张鹏[1] 王刚[2] 张涛[1] 陈年来[1] 

机构地区：[1]甘肃农业大学资源与环境学院,兰州730070 [2]兰州大学生命科学学院,兰州730000

出　　处：《植物生态学报》2010年第2期125-133,共9页Chinese Journal of Plant Ecology

基　　金：国家"十一五"支撑计划(2007BAD46B03)

摘　　要：以分布于祁连山北麓中段的两种优势乔木祁连圆柏(Sabina przewalskii)和青海云杉(Picea crassifolia)为研究对象,分析了高山乔木叶片δ13C值对海拔(2600-3600m)、土壤含水量和叶片含水量、叶片碳氮含量的响应及其机理。结果表明,这两种乔木叶片δ13C值均随海拔升高呈增重趋势,与海拔呈显著正相关关系(p<0.0001)。海拔2600-3600m阳坡树种祁连圆柏叶片的δ13C值显著高于同海拔梯度阴坡树种青海云杉。祁连圆柏和青海云杉叶片的δ13C值均与年平均气温呈显著负相关关系(p<0.0001),与年平均降水量呈显著正相关关系(p<0.0001)。祁连圆柏叶片δ13C值与土壤含水量(p<0.0001)、叶片含水量(p=0.01)和叶片碳氮比(C/N)(p<0.0001)呈显著正相关关系,与叶片全氮呈显著负相关关系(p<0.0001)。而青海云杉叶片δ13C值与土壤含水量、叶片全氮、叶片碳氮比和叶片含水量不相关。说明海拔变化引起的水热条件的改变,尤其是温度变化对高山乔木叶片碳同位素分馏起主要作用,但各个因子综合对高山植物叶片碳同位素分馏的作用机制可能比较复杂,需进一步深入研究。Aims Sabina przewalskii and Picea crassifolia, widely distributed in the Qilian Mountains, were employed to analyze the response of leaf δ^13C of subalpine trees to altitude and its mechanism. Methods Leaf samples were taken at 2 600-3 600 m elevation in October 2007. The δ^13C was determined using an isotope mass spectrometer, carbon content was estimated with the potassium dichromate method and nitrogen content was measured with the micro-Kjeldahl method. Data were evaluated with one-way analysis of variance and correlation analysis using SPSS version 11.5.Important findings Foliar δ^13C in both species was positively related to elevation （p 〈 0.000 1） and annual mean precipitation, but negatively related to annual temperature （p 〈 0.000 1）. The δ^13C value of S. przewalskii increased as leaf and soil water content increased, while that of P. crassifolia was not significantly related to soil water content, leaf water content, leaf N content or C/N ratio. Altitude, which can lead to changes of hydrothermal conditions, is the main factor influencing carbon isotope fractionation in these subalpine trees; however, the combined effects of various factors on the mechanism of action maybe more complicated and need further study.

关 键 词：海拔响应 机理 叶片δ~13C值 青海云杉 祁连山 祁连圆柏 

分 类 号：S718.4[农业科学—林学] Q945[生物学—植物学]