Removal of epicuticular wax has no effect on the rate of cuticular wax deposition, which is constant in mature cherry laurel leaves

O_LIThe plant cuticle, multifunctional hydrophobic air-to-plant boundary, vary dramatically among plant species and responds dynamically to environmental and biotic factors. These dynamics, certainly driven by cost-benefit selection, are poorly understood up to now. C_LIO_LI13C labelling and compound-specific isotope analysis open a new avenue to study the cuticle dynamics. We studied side specific leaf cuticular wax regeneration, in different compounds, and separately for intra-(IW) and epicuticular wax (EW), as well as the effect of epicuticular wax removal on the regeneration rate. C_LIO_LIMature leaves that reached the final area before the start of the experiment deposited new IW at first, but quickly equilibrated with EW. Removal of EW accelerated this equilibration but not the net rate of new wax deposition. The n-alkanes had the fastest turnover. Pentacyclic triterpenoids (ursolic acid) had a surprisingly slow turnover due to the large pool but also slow deposition rate. Adaxial and abaxial leaf surfaces exhibited small but consistent differences. C_LIO_LIWe demonstrated for the first time that EW removal does not affect wax deposition rate in evergreen leaf cuticle. We also confirmed that collodion discriminates between EW and IW well and does not inhibit future leaf metabolism and wax deposition in our species. C_LI