Epicuticular waxes of Salix species in relation to their overwintering survival and biomass productivity

Abstract

The epicuticular leaf waxes of nine willow clones (one Salix myrsinifolia, four Salix dasyclados, one Salix hybrid and three Salix viminalis clones) with different overwintering survival rates and biomass productivities were analysed by combined gas chromatography-mass spectrometry. The waxes were composed of n-alkanes (C 21C 31), long-chain aliphatic esters (C 36C 58), n-alcohols (C 20C 30), n-aldehydes (C 24C 30) and saturated free fatty acids (C 16C 30). Two types of waxes were observed. The S. viminalis clones had n-alkanes as their major wax component and n-docosanol as their major n-alcohol, whereas the other clones contained approximately equal proportions of n-alkanes, free fatty acids, n-alcohol and n-aldehydes and had n-hexacosanol as their major n-alcohol. The total epicuticular leaf wax contents varied from 3 μg cm −2 to 24.9 μg cm −2 and epicuticular n-alkane contents from 0.7 μg cm −2 to 14.8 μg cm −2. A correlation between high wax content, high n-alkane content, two overwintering survival and high biomass productivity of the clones was observed.