Role of ethylene in flower senescence of Gypsophila paniculata L

Flowers on Gypsophila paniculata L. plants senesced about 10 days after the onset of opening. The first indication of senescence was translucency of the petals, followed by desiccation. In harvested panicles kept in water, the flowers lasted for 4 days prior to petal wilting, 6 days when 200 mg I 1 Physan (a disinfectant) was included in the vase solution, and 10 days when both Physan and sucrose (15 g 1-I)were included. Petal wilting was preceded by a sharp rise in ethylene production. Treatment directly after harvest with silver thiosulphate (4 mM) for 30 min increased flower longevity in each of the foregoing solutions. In cut panicles, young flowers and buds also wilted, and panicle wilting was delayed by two days if stems were held at 90% RH rather than at 60%. It is concluded that petal senescence in G. paniculata is regulated by ethylene, and that early senescence of the flowers on cut panicles is related to ethylene production which is apparently caused by adverse water relations. Translucency, the first indication of impending senescence, is a result of infiltration of cell sap into the apoplast