EFFECTS OF ENVIRONMENT ON THE COMPOSITION OF EPICUTICULAR WAX FROM KALE AND SWEDE

The composition of leaf epicuticular waxes of two genotypes each of ka le and swede were determined by gas chromatography-mass spectrometry. Plants were grown indoors (I) and outdoors (O) at SCRI, Scotland, and outdoors at Wadenswil in Switzerland (S). Epicuticular waxes from outd oor-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 alcohol s than waxes from (I)-grown plants. Outdoor-grown plants were also fou nd to have proportionally more shorter chain length compounds and indo or-grown plants proportionally more compounds of longer chain length. Variations in wax composition between genotypes of a species and betwe en species were also observed. Differences in leaf surface wax ultrast ructure, between species, and between different growth conditions were detected using scanning electron microscopy. The possible role of lea f wax chemicals in the antixenotic resistance to the turnip root fly, Delia floralis, of certain genotypes was also considered.