Composition of epicuticular waxes on barley spikes

Abstract

Hydrocarbons, alkan-1-ol and alkan-2-ol containing esters, β-diketones, aldehydes, primary alcohols, hydroxy-β-diketones, free fatty acids and sometimes secondary alcohols are major lipid classes of epicuticular waxes on the spikes of the three wild type barley varieties Bonus, Foma and Carlsberg-II and many of the 40 eceriferum (cer) mutants examined. Division of the spikes into two parts, the awns and the spike minus awns, before wax isolation reveals that (i) β-diketones, hydroxy-β-diketones and esterified alkan-2-ols occur only on the spike minus awns, (ii) secondary alcohols are present only on the awns of Foma and its mutants and (iii) the other lipid classes are found on both parts of the spike. The chain length distributions of the lipid classes common to both parts of the spike are in some cases similar and in others different. © 1976 Carlsberg Laboratory.