Effects of ethylene and dehydration on cut flowering stems of Verticordia spp

Abstract

The potential for ethylene-induced abscission among Verticordia species used for cut flowers (V. nitens, V. chrysantha, V. plumosa, and V. densiflora) was studied by treating them with 2-chloroethyl-phosphonic acid (ethephon) or exposing them to dilute ethylene gas. The possibility that ethylene production induced by water stress may cause flower abscission was also investigated. Dipping in ethephon (500 or 1000 mg/L) failed to induce flower abscission in V chrysantha or V plumosa. Treatment with ethylene (8.6 pL/L) failed to induce flower abscission in V. densiflora. Ethephon and ethylene both induced substantial flower, pedicel, and leaf abscission in V. nitens. Pretreatment with silver thiosulfate prevented ethylene-induced flower abscission in V nitens. Dehydrating stems for periods of 6, 12, 24, or 48 h at about 20¦C did not induce flower abscission in either V plunzosa or V nitens. Dehydration periods of 6 and 12 h had no effect on longevity. Longer drying periods (24 and 48 h) induced early loss in appearance (visual quality) of both species.