An introduction to the scent of cacti

Abstract

The family of Cactaceae consists of around 1500 species in about 100 genera, being mostly leafless trees or shrubs of succulent appearance and often having attractive flowers. In comparison to other families, e.g. Orchidaceae, the flowers of Cactaceae are of a morphologically primitive structure. Nevertheless, they show adaptive traits towards different groups of pollinators. Adaptations are reflected to a certain degree also in their scent composition as illustrated by the selection of analytical data presented in this overview. Special attention is given to night-scented species flowering in most cases only during one night and being pollinated either by moths or by bats. The representatives of the first group show similarities in their scent composition to well-known moth flowers in other families, while the second group is dominated by repulsive garlic or cabbage-like odours caused by large amounts of sulphur-containing compounds such as dimethyl disulphide and methyl thioacetate. Among the scent components of the diurnal species, being pollinated by bees or a mixed spectrum of insects, the musty-earthy smelling dehydrogeosmin and geosmin deserve special attention. Furthermore, some additional structurally and/ or olfactorily interesting constituents occumng in the cacti scents are highlighted.

Mammal pollinators lured by the scent of a parasitic plant

“…Alternatively, the compound may be effective for attraction of small mammals because it is indicative of certain foods. Interestingly, although 3-hexanone is not a component of most floral scents [3], it occurs in the scents of a variety of neotropical bat-pollinated species, including as a major component of members of the Bromeliaceae and Bignoniaceae [12] and as a minor component of members of the Amaryllidaceae [12] and Cactaceae [33].…”

Floral Scent Contributes to Interaction Specificity in Coevolving Plants and Their Insect Pollinators

“…Recent work on the coevolving interactions between woodland star plants (Saxifragaceae: Lithophragma) and their pollinating floral parasites in the Greya moth genus (Prodoxidae) has shown that these closely related plants have an extraordinarily diverse set of floral scents that vary markedly among species and even subspecies , at levels comparable to differences between genera in other studies (e.g., Kaiser and Tollsten 1995;Levin et al 2001). The production of such a diverse array of compounds is likely to incur energetic (Gershenzon 1994;Wright and Schiestl 2009) and ecological costs, because the same compounds that attract mutualistic insects also may attract antagonistic herbivores and seed predators (Irwin et al 2004;Proffit et al 2007;Schiestl et al 2011;Theis 2006;Theis and Adler 2012;Wright and Schiestl 2009).…”

The missing stink: sulphur compounds can mediate a shift between fly and wasp pollination systems

“…Solvent samples (E. bicolor S1 and E. humilis S1, see electronic supplementary material, table S2, for sampling details) were analysed by Dr Roman Kaiser (Givaudan, Switzerland) using methods described in Kaiser & Tollsten (1995). Thermal desorption samples (five for each species; see electronic supplementary material, table S2, for sampling details) were analysed on a Varian CP-3800 GC (Varian, Palo Alto, CA, USA) coupled to a Varian 1200 quadrupole mass spectrometer with a Varian 1079 injector equipped with a 'ChromatoProbe' thermal desorbtion device using methods described in Shuttleworth & Johnson (2009a).…”