Musty‐Earthy Scent in Cactus Flowers: Characteristics of Floral Scent Production in Dehydrogeosmin‐Producing Cacti

Abstract

The musty‐earthy‐smelling sesquiterpenoid dehydrogeosmin (DHG) was found several years ago as a novel compound in flowers of some cactus species, which called attention to the biology of floral scents of the Cactaceae. Our studies showed that the odor bouquet of DHG‐producing cactus flowers is dominated by isoprenoids. All floral volatiles were produced by the perianth during the exclusively diurnal anthesis. Volatile emissions were diurnal, as was the daily opening schedule of flowers. Within one species, the odor composition of cultivated specimens varied strongly, whereas little variation was found among individuals of a natural population of the same species. However, field studies revealed that DHG is not produced by all specimens in natural populations. Our results on the timing and location of odor emission support the hypothesis that this unusual volatile may play a role in pollinator‐plant interactions.