Ornamental cabbage (Brassica oleracea var. acephala f. tricolor) cultivars of Japanese seed companies are grown in Europe. Unpleasant odors from cut flowers have become a problem in this region. We investigated volatiles emitted from cut flowers of 'Hatsubeni' and 'Haresugata', two major Japanese ornamental cabbage cultivars in Europe, by gas chromatography-mass spectrometry (GC-MS). Dimethyl disulfide was identified as the major odor-active component emerging from plants as well as from vase water. Vase water was a major source of unpleasant scents, and odor development was prevented by changing the water frequently. We tested the effects of potential suppressors of dimethyl disulfide emission from cut flowers applied to vase water. Cyprodinil, an inhibitor of the synthesis of dimethyl disulfide from methionine, and aminooxyacetic acid, an inhibitor of enzymatic reactions involved in dimethyl disulfide biosynthesis, did not show any effects. In contrast, isothiazolinonic germicide, a cut-flower preservative, inhibited the rot of cut ends of flower stems and reduced dimethyl disulfide emission from cut flowers by 30-40%. In addition, this germicide significantly inhibited emissions from vase water. Isothiazolinonic germicide is a promising candidate inhibitor of unpleasant scents from cut flowers of ornamental cabbage.

A new blue petunia cultivar, TX-794 bred by Takii & Co., Ltd, has a sweet floral fragrance different from conventional petunia cultivars that typically have no odor or have a somewhat unfavorable smell. Since fragrant bedding plants suitable for summer cultivation are rare, we expect that the fragrance will enhance the value of TX-794. The characteristics of emitted scent compounds from TX-794 were evaluated in this study. The major scent compound was phenylacetaldehyde, a C6-C2 aromatic compound that was emitted at higher levels in TX-794 compared to conventional petunia cultivars. iso-Eugenol, a C6-C3 aromatic compound, is the major scent compound in conventional petunia cultivars. These results suggest that TX-794 has a high capacity to biosynthesize C6-C2 aromatic compounds, resulting in a significantly different scent compound composition compared to conventional petunia cultivars. Time-course analysis of scent compound emission revealed that the largest release of scent compounds by TX-794 occurs during the switch from light periods to dark periods. Soon after flowering, that is, in the light period on the day of anthesis, the major scent compound was p-cresol. Thereafter, the primary scent compound was phenylacetaldehyde or methyl benzoate with 2-phenylethanol occupying the next position. Since a bed or a container of petunias has flowers that are primarily over 2-days old, the basic fragrance of TX-794 plants is derived from phenylacetaldehyde, which has a hyacinth-like scent, 2-phenylethanol, which has a rose-like scent, and methyl benzoate, which has a dry fruitlike scent.