摘要
n-Alkanes and their carbon and hydrogen stable isotopes were analyzed in grasses, reeds and tree leaves from five regions with latitudes of 22° to 39° in China using GC-MS and GC-TC-IRMS techniques. In this study, it is found that a change of ACL units for crossing 1 latitude and increasing 1 ℃ is 0.08 for grass, 0.22 for reed and 0.36 for tree leaves and 0.04 for grass, 0.24 for reed and 0.20 for tree leaves, respectively. The δ13C values of C27 and C29 n-alkanes in the studied plants ranges from -25.3‰ to -35.5‰ and the grass has a lighter mean carbon isotopic composition than the reed and tree leaves. The δD values of C27 and C29 n-alkanes in the plants are between -132.1‰ and -192.6‰ and the mean hydrogen isotopic compositions of C27 and C29 n-alkanes in the grass are lighter than those in the reed and tree leaves. C27 and C29 n-alkanes in the grass and tree leaf samples from high latitude and elevation area have relatively light hydrogen isotopic composition.