Induction of flower senescence and gynaecium development in the carnation (Dianthus caryophyllus)by ethylene and 2-chloroethylphosphonic acid

SummaryThe absorption of solutions of 2-chloroethylphosphonic acid (CEPA) or 2, 4-di-chlorphenoxy acetic acid (2, 4-D) at 100 mg l-1 through cut stems, or of ethylene gas, accelerated the senescence of cut carnation flowers. Accelerated growth of the ovary wall, placenta and receptacle accompanied wilting of petals, a typical symptom of senescence, both in the intact or cut flower. Fresh weight, dry weight and girth of the ovary were significantly greater in flowers treated with CEPA orr 2, 4-D than in controls held in water. The CEPA treatment was less effective in promoting dry weight increase of the ovary if the petals were removed. CEPA and 2, 4-D released ethylene or induced its formation in the carnation flower.On the grounds that growth changes in the ovary, induced by ethylene, simulate natural pollination and fertilization, except for seed development, it is postulated that ethylene acts as a terminal growth regulator in the carnation.