Volatile compounds emitted by rose cultivars: Fragrance perception by man and honeybees

Abstract

Petals of 11 rose cultivars were analyzed by solvent extraction for the presence of key scent volatiles. Two different cultivars-'Fragrant Cloud', a very fragrant cultivar, and 'Golden Gate', a non-fragrant cultivar-were further analyzed by the headspace technique during flower opening. The 'Fragrant Cloud' headspace is composed of a variety of volatiles, including monoterpene alcohols, acetates, and terpene hydrocarbons, while the 'Golden Gate' headspace is composed mainly of orcinol dimethylether, a compound that is scentless to the human nose but that is perceived by honeybees, as judged by proboscis extension experiments. In both cultivars, the level of volatiles increased during flower development, while the ratio of different major volatiles remained constant.

Both the adaxial and abaxial epidermal layers of the rose petal emit volatile scent compounds

“…This is a very general feature, which has been observed in a wide range of species including Clarkia breweri (Pichersky et al 1994), A. majus and diVerent rose cultivars Picone et al 2004;Shalit et al 2004). This link between emission of scent and the opening of the Xower is generally related to the capacity of the Xower to attract pollinators (Negre et al 2003).…”

“…In these wild roses, from which R. £ hybrida is derived, Xoral odors are thought to be chemical signals between the plant and insects, the latter including both pollinators and predators (Picherky and Gershenzon 2002). In R. £ hybrida, we show that petal and stamen odors are dominated by monoterpene alcohols and 2-phenylethanol, which are known insect attractants (Dobson et al 1999;Shalit et al 2004). As in R. rugosa, the proportion of eugenol is high in stamens.…”

“…For example, Kovats (1987) identiWed more than 127 components in the essential oil of Rosa damascena, including trace components of high importance for the odour impact of the oil. Later, various headspace techniques were used, providing a more precise description of the scent emitted by numerous rose cultivars (Nakamura 1987;Shalit et al 2004). More recently, researchers have focused on physiological aspects of rose scent emission, with particular emphasis on its circadian rhythmicity (Picone et al 2004).…”

Scent evolution in Chinese roses

“…Taken together with the observation that OOMT proteins accumulate to high levels only in petals of roses that produce PME, the data presented here indicate that Chinese roses evolved their ability to produce these scent compounds as a result of a combination of increased OOMT gene expression in petals and the evolution of more catalytically active enzymes. Because DMT has been shown to be perceived by bees (28,29), evolution of the PME biosynthetic pathway in Chinese roses might therefore have provided distinctive olfactory cues for insect pollinators.…”

Plant Phenylacetaldehyde Synthase Is a Bifunctional Homotetrameric Enzyme That Catalyzes Phenylalanine Decarboxylation and Oxidation

“…nylethanol, and its acetate ester are important scent compounds in numerous flowers (5), including petunias (7,8) and roses (9). They also contribute to the aromas of tomato (6), grape (10), and tamarind (11) fruits and to the flavor of tea (12).…”