Effects of environment on the composition of epicuticular wax from kale and swede

Abstract

The composition of leaf epicuticular waxes of two genotypes each of kale and swede were determined by gas chromatography-mass spectrometry. Plants were grown indoors (I) and outdoors (O) at SCRI, Scotland, and outdoors at Wädenswil in Switzerland (S). Epicuticular waxes from outdoor-grown plants (O and S) were found to have higher proportions of n-alkanes, octacosanoic acid, primary alcohols and long-chain esters but lower proportions of aldehydes, ketones, ketols and secondary alcohols than waxes from (I)-grown plants. Outdoor-grown plants were also found to have proportionally more shorter chain length compounds and indoor-grown plants proportionally more compounds of longer chain length. Variations in wax composition between genotypes of a species and between species were also observed. Differences in leaf surface wax ultrastructure, between species, and between different growth conditions were detected using scanning electron microscopy. The possible role of leaf wax chemicals in the antixenotic resistance to the turnip root fly, Delia floralis, of certain genotypes was also considered.