Composition of Volatiles in Relation to Taxonomy of American Alliums

Abstract

The North American species of Allium exclusive of A. schoenoprasum and A. tricoccum of Old World affinity are grouped on the basis of morphological similarity into eight discontinuous species alliances typified by A. acuminatum, A. campanulatum, A. canadense, A. cernuum, A. falcifolium, A. kunthii, A. sanbornii, and A. validum, respectively. Representatives of each of these alliances were compared with respect to volatile constituents responsible for characteristic odors by means of gas chromatography. Results indicate that these volatiles provide evidence of relationship useful in the classification of alliums. Uniformity was found in composition of volatiles in the representatives of the A. canadense, A. cernuum, A. kunthii, and A. sanbornii alliances. Variation was observed in the A. acuminatum, A. campanulatum, and A. falcifolium alliances. A. validum was the only species of its alliance studied. Vapors of A. validum contain mostly n‐propyl sulfides (onion‐like odor) as does the cultivated A. cepa. Methyl sulfides (cabbage‐like odor) predominate in the A. sanbornii alliance. A few species of the A. acuminatum and A. falcifolium alliances contain mainly allyl sulfides (garlic‐like odor).

NUMERICAL TAXONOMIC STUDIES ON SPECIES IN ALLIUM SUBGENUS RHIZIRIDEUM

“…Volatile sulphides produced after tissue damage have been investigated, since it has been shown (Saghir, Mann and Yamaguchi, 1965;Saghir, Mann, Ownbey and Berg, 1966;Bernhard, 1970;Freeman and Whenham, 1975) that there is substantial variation between taxa of Allium in the composition of the sulphides produced and that these are readily separable by gas-liquid ehromatography.…”

“…Since the sections used by all these authors are distinguished by only a small number of characters it was thought worthwhile to study a sample of rhizomatous taxa for a relatively large number of morphological and cytological characters and to compare classifications produced from these data with others derived from a set of chemical characters. Volatile sulphides produced after tissue damage have been investigated, since it has been shown (Saghir, Mann and Yamaguchi, 1965;Saghir, Mann, Ownbey and Berg, 1966;Bernhard, 1970;Freeman and Whenham, 1975) that there is substantial variation between taxa of Allium in the composition of the sulphides produced and that these are readily separable by gas-liquid ehromatography.…”

A Revision of the Allium Fimbriatum (Alliaceae) Complex

“…Alliumfimbriatum sensu Ownbey was one of a group ofNorth American species referred to the A. sanbornii alliance by Ownbey (Saghir et al 1966). Species in this alliance are characterized by a solitary terete leaf and an ovarian crest formed by six prominent and nearly triangular flattened processes, two near the summit of each of the three ovary lobes.…”

L'Allium ampeloprasum(var.bulbilliferumLloyd) de l'Ile d'Yeu (Vendée) est chimiquement un ail et non un poireau

“…Comme la plupart des Allium, il possède des substances soufrées dont certaines sont volatiles (thiosulfinates ct sulfures d'alkyles). La détermination, dans un but taxonomique, de la proportion relative des groupements alkyles a déjà été utilisée pour des A ilium sauvages de l'Ancien et du Nouveau Monde (Saghir et al, 1966 ;Bernhard et Richard, 1970 ;Fr·eeman et Whenham, 1975). Il est par ailleurs bien Downloaded by [91.216.3.177] at 08:32 05 June 2016 établi chez les Allium cultivés que le poireau renferme surtout des produits volatils thiopropyüques (Auger et al .• 1989) et l'ail des produits volatils thioallyliques .…”