The effects of ethylene on the postharvest development of fruits and vegetables have
been extensively studied. However there are many plant hormones whose potential utility
in postharvest technology needs to be explored. Plant hormones rarely, if ever, function
alone. Even in cases in which a response can be evoked by application of a single hormone,
the tissue may contain additional endogenous hormones that contribute to the response.
Senescence is controlled by hormones; growth stimulators (auxins, gibberellins and
cytokinins) delay it, and growth inhibitors (ethylene and abscisic acid) speed up the
senescence process. Ripening in fruit may be retarded by applying inhibitors of respiration
and ethylene production at postharvest; however, the ripening process, once started, cannot
be reversed.