POLLINATION-INDUCED CHANGES IN ETHYLENE PRODUCTION AND SENSITIVITY TO ETHYLENE IN CUT DENDROBIUM ORCHID FLOWERS

The longevity of cut dendrobium orchid (Dendrobium hybrid, cultivar 'Jaquelyn Thomas') flowers is normally 3 weeks. After pollination however, there is a rapid acceleration of the wilting process, beginning after only 24 h. Enhancement of senescence was induced only by successful pollination and not by emasculation. Following pollination there was an increase in both ethylene production and the sensitivity to ethylene. The increase in ethylene production began about 12 h after pollination and reached its peak after 30 h. An increase in ethylene sensitivity following pollination was not dependent on endogenous ethylene production as it occurred also in flowers treated with (aminooxy)acetic acid, an inhibitor of ethylene biosynthesis, which greatly reduced ethylene production levels.