To clarify whether climacteric-like increases in
ethylene production of senescing petals are also induced in the absence of the gynoecium in cut carnation (Dianthus caryophyllus cv. Barbara) flowers, we compared
ethylene production and expression of
ethylene-biosynthesis genes in detached petals and in petals, which remained on flowers (attached petals). No significant difference in longevity was observed between the attached and detached petals when held in distilled water, and both showed the inward rolling typical of senescing flowers. Treatment with
silver thiosulfate complex (STS), an
ethylene inhibitor, similarly delayed senescence of attached and detached petals. Climacteric-like increases in
ethylene production of petals and gynoecium started on the same day, with similar bursts in attached and detached petals. Transcript levels of DcACS1 and DcACO1 were very low at harvest and increased similarly during senescence in both petal groups. Removal of the gynoecium did not significantly delay wilting of attached petals. In flowers with the gynoecium removed, the petals produced most of the
ethylene while production by the other floral organs was very low, suggesting that
wound-induced
ethylene is not the reason for the ineffectiveness of gynoecium-removal in inhibiting flower senescence. These results indicate that
ethylene biosynthesis is induced in carnation petals irrespective of the gynoecium.