Floral Scent Production in Antirrhinum majus

Abstract

Despite the economic importance of floral scent for plant reproduction, little is known about the molecular mechanisms of floral scent production. Floral scent is often a complex mixture of low-molecular-weight compounds that are mainly distributed within three groups: fatty acid derivatives, benzenoids, and isoprenoids. Esters of such compounds are the most widespread type. Headspace analysis in combination with gas chromatography and mass spectrometry of volatiles emitted from snapdragon flowers revealed that methyl benzoate is one of the major components of the `Maryland True Pink' genotype. The activity of novel enzyme S-adenosyl-l-methionine:benzoic acid carboxyl methyltransferase (BAMT), which catalyzes the methyl esterification of benzoic acid, was analyzed in different floral tissues and at different stages of flower development. It has been found that BAMT activity is highest in petals, both upper and lower lobes, and very low or absent in other floral tissues and leaves. No detectable BAMT activity was found in flower buds 1 day before flower opening. During the lifespan of the flower the level of BAMT activity in petal tissue increases gradually and remains high in old flowers.