Re-examining the reliability of tree-ring isotope ratio as a historical CO_2 proxy  

作　　者：HOU Aimin, PENG Shaolin, ZHOU Guoyi & WEN DazhiSouth China Institute of Botany, Chinese Academy of Sciences, Guangzhou 510275, China 

出　　处：《Chinese Science Bulletin》2001年第1期17-21,共5页

基　　金：This work was supported by the National Natural Science Foundation of China (Grant No. 39899370 ); the Natural Science Foundation of Guangdong Province (Grant No. 980952) ;the Chinese Academy of Sciences (Grant Nos. KZ951-B1-110 and KZ95T-40-02- 03).

摘　　要：To examine the reliability of using tree ring δ13C and the model of isotopic fractionation in reconstructing atmospheric CO2 levels, we studied the variations of some important parameters of several subtropical species under natural field conditions. It was found that, different from other researchers’ results, leaf conductance to CO2 transfer, g, did not change in proportion to the change in rate of CO2 assimilation, A, with the result that intercellular concentration of CO2, Ci, could not keep constant. Thus, we conclude that the use of tree-ring isotope ratios in the reconstruction of atmospheric CO2 variation based on the presupposition that Ci keeps constant during assimilation is not reliable under current circumstances.To examine the reliability of using tree ring δ13Cand the model of isotopic fractionation in reconstructingatmospheric CO2 levels, we studied the variations of some important parameters of several subtropical species under natural field conditions. It was found that, different from other researchers' results, leaf conductance to CO2 transfer, g, did not change in proportion to the change in rate of CO2 assimilation, A, with the result that intercellular concentration of CO2, Ci, could not keep constant. Thus, we conclude that the use of tree-ring isotope ratios in the reconstruction of atmospheric CO2 variation based on the presupposition that Ci keeps constant during assimilation is not reliable under current circumstances.

关 键 词：A/g CI TREE-RING ISOTOPE ratio reconstruction ATMOSPHERIC CO2 variation. 

分 类 号：Q945[生物学—植物学]