摘要：Based on the experimental results from seven subtropical species,in contrast with other researchers...Based on the experimental results from seven subtropical species,in contrast with other researchers′ results, the parameter Ci/Ca （ratio of substomatal CO2 to atmospheric CO2 concentration）is not stable,but varies with species and environmental factors,especially light intensity.Thus,we concluded that the use of tree-ring isotope ratios in the reconstruction of atmospheric CO2 isotope ratio δa variation,which is based on the assumption that Ci/Ca keeps stable during assimilation,is not reliable under current circumstances.显示全部
