Seasonal variation of leaf wax n-alkane production and δ²H values from the evergreen oak tree, Quercus agrifolia

Abstract

In order to understand the timing of leaf wax synthesis in higher plants, we analysed the variability in leaf wax n-alkane concentration, composition (expressed as average chain length (ACL)), and δ²H_wax values as well as plant source water δ²H values (xylem and leaf water) in the evergreen tree Quercus agrifolia over a period of 9 months, beginning with leaf flush. We identified three distinct periods of leaf development with the first month following leaf flush being characterized by de novo synthesis and possibly removal of n-alkanes. During the following 3 months, n-alkane concentrations increased sevenfold and δ²H_wax and ACL values increased, suggesting this period was the major leaf wax n-alkane formation period. During the remaining 4 months of the experiment, stable values suggest cessation of leaf wax n-alkane formation. We find that n-alkane synthesis in Q. agrifolia takes place over 4 months, substantially longer than that observed for deciduous trees.

Keywords:

• hydrogen-2
• isotope ecology
• n-alkanes
• leaf wax
• oak tree

Acknowledgements

The authors would like to thank Johanna Menges (University of Potsdam) for help with lipid extraction and quantification.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the German Research Foundation (DFG) through an Emmy-Noether Research Grant (DS1889/1–1) to D.S. and by an ERC Starting Grant (279518 COSIWAX) to A.K.