Epi- and intracuticular lipids and cuticular transpiration rates of primary leaves of eight barley (Hordeum vulgare) cultivars

The major constituents of the epi- and intracuticular lipids of primary leaves of 8 cultivars of barley ( Hordeum vulgare L.) have been studied together with cuticular transpiration rates. The total amount of analysed cuticular lipids ranged from 9.6 to 13.4 μg cm^?2 and was dominated by the epicuticular fraction, which made up 73–84% of the total. There were variations in the percentages of the analysed lipid classes, alkanes, esters, aldehydes, β-diketones and alcohols, between epi- and intracuticular lipids among individual cultivars, but no clear tendency in these variations, except for the aldehydes, was found. The epicuticular lipids were richer in aldehydes than the intracuticular lipids. The cuticular transpiration rates were poorly correlated with the levels or composition of epi-, intra- or total cuticular lipids. The cuticular transpiration rates were considerably altered as a response to a water stress treatment, but these changes could not be correlated with any changes in amount or composition of the cuticular lipids. From these results it is concluded that some property other than amount or composition of cuticular lipids is the most important in regulation of water diffusion through the cuticle.