Inhibition of<i>Pinus radiata</i>Primary Needle Epicuticular Wax Biosynthesis by Trichloroacetate

Abstract

High concentrations (1000 parts 10−6) of trichloroacetate (TCA) inhibit germination of Pinus radiata seed. Seedlings growing in the presence of lower concentrations (100 parts 10−6) take up TCA where it becomes concentrated in cotyledons and developing primary needles. TCA inhibits biosynthesis of nonacosan-10-ol and long chain diol constituents of the primary needle epicuticular wax concomitant with a reduction in appearance of tubular wax except around stomatal pores. Epicuticular wax from TCA-treated plants consists mainly of alkyl esters, and is amorphous. It is suggested that P. radiata stomatal subsidiary cells possess tubular epicuticular wax chemically distinct from that of epidermal cells.