秦岭桦树树轮纤维素氧同位素的年内变化特征及其气候意义  

Characteristics of intra-annual variations in oxygen isotopers of birch treering cellulose in the Qinling Mountains and their climatic significance

作　　者：何荣[1] 马然 赵雨 祁瑶婷 HE Rong;MA Ran;ZHAO Yu;QI Yao-ting(College of Chemistry and Chemical Engineering,Isotopomics in Chemical Biology,Shaanxi University of Science&Technology,Xi′an 710021,China;Shaanxi Key Laboratory of Chemical Additives for Industry,Shaanxi University of Science&Technology,Xi′an 710021,China)

机构地区：[1]陕西科技大学化学与化工学院天然产物稳定同位素组学实验室,陕西西安710021 [2]陕西科技大学陕西省轻化工助剂重点实验室,陕西西安710021

出　　处：《陕西科技大学学报》2024年第2期116-123,131,共9页Journal of Shaanxi University of Science & Technology

基　　金：国家自然科学基金项目(42007408,41973072);中国博士后科学基金面上项目(2019M650253)。

摘　　要：树轮氧同位素的生理机制较为明确,且具有分布范围广、连续性强等优点,常被用于古气候、古环境的重建研究.年际树轮氧同位素已被成功用于气候信息(如源水、温度、相对湿度等)的重建,年内高分辨率的树轮氧同位素则记录了更加丰富的年内气候变化信息.以秦岭南坡桦树(落叶阔叶植物)为研究对象,本文开展了年内高分辨率树轮全样及纤维素样品的碳、氧同位素分析,同时分析了树轮纤维素分子内的氧同位素组成,即树轮纤维素分子内2号位氧原子(δ^(18)O_(2))和3~6号氧原子(δ^(18)O_(3~6)).通过模拟树木径向生长变化,并结合基于日尺度气象数据的降雨氧同位素模拟结果.结果表明:桦树树轮年内全样以及α-纤维素的δ^(13)C和δ^(18)O的变化趋势符合年内树轮同位素的变化规律;在生长旺季(7~8月),桦树树轮α-纤维素氧同位素(δ^(18)Oα-cell)与温度呈正相关、与相对湿度和降水量呈负相关(相关系数R分别为0.81、-0.84、和-0.69);生长旺季的树轮α-纤维素分子内2号位氧原子的同位素组成(δ^(18)O_(2))与源水的氧同位素(δ^(18)O SW)具有一定的相关性(R=0.58).Stable oxygen isotope ratios in tree ringα-cellulose(δ^(18)Oα-cell)has been turn out to be a powerful tool for climate reconstruction,such as to explore long-term precipitation patterns,seasonality of precipitation,and intra-annual patterns of transpiration rates.High-resolutionδ^(18)Oα-cell could track the short-term seasonal course of climate.In this context,we investigated the seasonal changes ofδ^(18)Oα-cell,δ^(18)O PG(Oxygen isotope analysis of phenylglucosazone,a compound which lacks the oxygen attached to the second carbon of the cellulose-glucose moieties),andδ^(18)O_(2)(^(18)O content of the oxygen attached to the second carbon of the cellulose-glucose moieties)of tree ring cellulose of Birch and their response to climatic parameters.By modelling changes in the radial growth of trees and incorporating the results of daily-scaled oxygen isotope modelling of precipitation based on meteorological date,the result show that:Bothδ^(13)C andδ^(18)O of tree rings bulk sample or cellulose in Birch showed obviously seasonal variation,during the growing season(July~August),δ^(18)Oα-cell)of Birch tree rings showed a positive correlative with temperature,and negatively correlative with relative humidity and precipitation(correlation coefficients R were 0.81,-0.84,and-0.69,respectively),the oxygen isotope composition of O-2(δ^(18)O_(2))in the tree-ringα-cellulose in the growing season showed certain correlation with the oxygen isotope of the source water(R=0.58).

关 键 词：稳定氧同位素 树木年轮 Α-纤维素 年内高分辨率 气候响应 

分 类 号：P597[天文地球—地球化学]