Quantitation of the major cuticular components from green leaf of different tobacco types

Surface chemicals of green tobacco leaf were obtained by dipping the leaf into methylene chloride. Leaf wash procedures were developed and evaluated for both small and large numbers of samples. Cuticular constituents containing alcohol functions were derivatized with trimethylsilyl reagents and analyzed by glass capillary gas chromatography on SE-54 columns. Quantitative data were obtained for the major cuticular diterpenoids a- and fl-4,8,13-duvatriene-l-ols, a- and j3-4,8,13-duvatriene-l,3-diols, cis-abienol, labda-13-ene-8,15-diol, and docosanol, hydrocarbons, and sucrose esters. The application of this method allowed the characterization of the cuticular constituents of numerous tobacco varieties and introductions. The relationships between cuticular composition and insect resistance are presented and discussed. The green leaves of commercial tobacco varieties are covered with a gummy exudate, and the composition of these cuticular waxes may be of significant importance. Dietrich and Demole (1977) and Enzell (1977) have reported that the degradation of the cuticular diterpenoids of green tobacco, during curing and aging, results in the production of numerous volatile terpenes, which may be important tobacco flavor components. Reid (1975) reported that a diterpene fraction, isolated from green leaf cuticular waxes, contained precursors of aroma constituents of commercial tobacco. Cutler et al. (1977) have found that the cuticular diterpenes of green tobaccos have plant growth inhibiting properties. The levels of specific cuticular components are believed to be responsible for the observed resistances of some types of tobacco to green peach aphids [Myzus persicae (Sulzer)], tobacco budworm [Heliothis uirescens (F.)], and tobacco hornworm [Muduca sextu (L.)] (Johnson and Severson, 1982,1984; Severson