A survey of epicuticular waxes among genera of Triticeae. 2. Chemistry

Abstract

During an extensive investigation of the composition of epicuticular waxes from members of the tribe Triticeae, 174 specimens of 123 species from 22 genera have been analyzed. Alcohol content and chain length, β-diketone, hydroxy-β-diketone, and oxo-β-diketone content and structure, and hydrocarbon and ester content have been determined. Sixteen characters have been derived from the results and examined by principal-coordinate and cluster analyses. The results showed considerable uniformity within the tribe; either alcohols, principally hexacosanol or octacosanol, or β -diketones were the major constituents of the wax, hydrocarbons and esters were always minor constituents. When genera were compared, Aegilops, Hordeum, and Roegneria were found to be more uniform than Agropyron, Elymus, Elytrigia, and Leymus but distinctive differences between most of the major genera were observed.