Shorter average chain length of n-alkanes from flowers than leaves of modern plants: Implications for the use of n-alkane-derived proxies in soils

Abstract

The average chain length (ACL) of leaf wax n-alkanes has been widely used to differentiate plant types and to reconstruct the paleoenvironment. However, it is still unclear whether or not the ACL differs significantly between different plant organs, in particular between flowers and leaves. Here, we collected flower and leaf samples from 18 plant species and compared the distribution of n-alkanes and n-alkane derived proxies. The abundance and distribution of n-alkanes from flowers differed remarkably from those of leaves. Flowers could produce high concentrations of n-alkanes, with the most abundant compound (C_max) for flowers being lower than or equal to that for leaves. The ACL values of flower n-alkane for all plant species were lower than those of leaf n-alkane. This suggests that the contributions of flower n-alkanes to soils need to be evaluated before n-alkanes are used for paleoclimate reconstruction.