树木年轮中不同组分稳定碳同位素含量对气候的响应  

Response of stable-carbon isotope composition of different tree-ring compounds to climatic change

作　　者：马利民[1] 刘禹[2] 赵建夫[1] 安芷生[2] 

机构地区：[1]同济大学污染控制与资源化研究国家重点实验室,上海200092 [2]中国科学院地球环境研究所黄土与第四纪地质国家重点实验室,西安710075

出　　处：《生态学报》2003年第12期2607-2613,共7页Acta Ecologica Sinica

基　　金：国家自然科学基金资助项目 (4 0 0 71 0 81 ) ;上海市科委资助项目 (0 2 DZ1 2 1 0 1 ) ;国家 973重点规划资助项目(G1 990 43 40 0 1 ) ;中国科学院知识创新工程资助项目 (KZCX2 -1 0 8) ;黄土与第四纪地质国家重点实验室基金资助项目(ZKLLQG2 0 0 0 1 6)

摘　　要：通过研究贺兰山油松树轮中全木、综纤维素、α-纤维素中δ13C值的变化 ,来探讨树木生长过程中引起其中同位素差别的原因 ,以及它们对环境变化的响应。研究发现不同组分的δ13C值在过去 30 a中变化并不一致 ,其中 ,树轮中 α-纤维素中 δ13C序列含有最强周围环境变化的信息。δ13C序列和周围大气平均气温和降雨量关系密切 ,其中和 6～ 8月份的平均气温相关系数为 0 .42 7( α=0 .0 5 ) ;和 2～ 7月份总降水量的相关系数为 ( r=- 0 .5 1 4,α=0 .0 1 )。分析发现树轮 α-纤维素序列和树轮宽度序列呈显著负相关 ( r=- 0 .5 4 5 ,α= 0 .0 1 )。对比树轮各种组分的 δ13C值和气候之间的相关性及和树木的生长量的关系可以发现 ,树轮 α-纤维素中碳在经历了光合作用的固碳过程中的同位素分馏后 ,其 δ13C值就保持了相对稳定 ,是研究过去环境变化的良好载体。The stable-carbon isotope ratio (()^(13)C/()^(12)C) of tree rings is an important proxy to research past climate change. Frequently, δ^(13)C has been measured on the cellulose component of wood xylem, but the question arises as to whether other wood components or even whole wood, could be analyzed to produce similar results. In this paper, cores were sampled from six Pinus tabulacforms trees at Mountain Helan, which is located at 38°31′N 105°46′E at an elevation 2400～2500 m above sea level. The area is one of the driest regions in northwest China, where tree growth is primarily limited by precipitation. After crossdating to establish the age of each ring, they were carefully separated from the cores under a binocular microscope to avoid carbon contamination. For each of the 30 years, rings were pooled from all cores, providing whole-wood tissue samples as well as holocellulose and α-cellulose extracted by standard methods. Each sample was combusted in a quartz tube with copper oxide and platinum wire at 800℃ for two hours to produce CO_2 that was analyzed on a Finnigan-MAT 251 mass spectrometer. Separate whole-wood tissue, holocellulose and α-cellulose δ^(13)C chronologies were thus developed for the 30-year period. Our results show that although there is high correlation among wood components, the climate relationships with δ^(13)C of tree-ring whole wood, holocellulose and α-cellulose are not uniformly strong. The strongest climate relationships involve α-cellulose, with δ^(13)C positively correlated with the average temperature from June to August (r=0.427, P<0.05) and negatively correlated with the precipitation from February to July (r=-0.514, P<0.01). The correlation coefficient for holocellulose with average June to August temperature is 0.327, and it is -0.481 with February to July precipitation. The same correlations for whole-wood tissue are -0.249 and 0.247, respectively. Additionally, the α-cellulose δ^(13)C is negatively correlated with tree-ring width (r=-0.545, P<0.01). These r

关 键 词：树木年轮 稳定碳同位素含量 环境变化 古气候 纤维素 组分 

分 类 号：S718[农业科学—林学]