Composition of Volatiles in Allium as Related to Habitat, Stage of Growth, and Plant Part

Abstract

The idea of using odor as a taxonomic character in Allium led to a consideration of the relationship of habitat, stage of growth, and plant part to the composition of volatiles on the genus. By gas-liquid chromatography, determinations were made of the proportion and concentration of volatile sulfides from chopped tissues of some Allium spp. collected from different habitats sampled at several stages of growth and from different parts of the plant. Neither habitat, nor stage of growth, nor plant part affected appreicably the proportions of methyl, n-propyi, and allyl radicals in the disulfides from the vapors of chopped tissue. However, the concentration of total sul-fides in the vapor increased steadily during growth until foliage leaves were fully developed. After flowering and senescence of the leaves, a decrease in concentration was observed in amounts of volatiles from the bulb tissue. The concentration of sulfides in the vapor from foliage leaves and from inflorescence stalks of A. christophi Trautv. were significantly higher than those from roots, inflorescences, or bulbs. The proportions of sulfide radicals do not vary significantly within spp. and, hence, this character would be useful in the classification of the genus Allium.