For that reason, plants of 10 dianthus species with fragrant flowers and one with little fragrance were selected for the purpose of identifying the main groups of chemicals that confer fragrance.
The volatile gases emitted by the flowers were collected and then analysed with a gas chromatograph. The flowers fell into four main groups. The first of these had a strong "medicinal" fragrance created mainly by benzenoids, among which were methyl salicylate and isoeugenol.
The second group emitted a citrus-like fragrance largely due to terpenoids, including beta-ocimene and beta-caryophyllene. The third group had a green leafy odour with floral scent due largely to fatty acid derivatives such as (Z)-3-hexenyl acetate. The fourth group emitted hardly any scent.
Species in the first group, which included D. hungaricus and D. pyrenaicus, appeared to be the most promising for introducing fragrance to carnation. The second group included D. superbus, which should also be a promising parent.
It was also noted that the fragrance of D. hungaricus was emitted mainly from the limb of the petal, which suggests that double flowers ought to be the most fragrant.
Dr Ken Cockshull, Associate Fellow, Warwick Crop Centre, University of Warwick.
Evaluation of Wild Dianthus Species as Genetic Resources for Fragrant Carnation Breeding Based on Their Floral Scent Composition by Kishimoto, Nakayama, Yagi, Onozaki and Oyama-Okubo (2011). Journal of the Japanese Society for Horticultural Science 80 (2): 175-181. The authors' abstract is available online at www.jstage.jst.go.jp/browse/jjshs1 from where the whole article can be downloaded as a PDF.