Ethylene sensitivity. All cultivars responded
to the application of exogenous
ethylene with increased petal abscission (Fig.
1). The sensitivity to ethylene varied among
cultivars with ‘Kim’ being the least sensitive
followed by ‘Veronica’ and ‘Cotton Candy’.
‘Fox’ was the most sensitive to ethylene,
abscising the most petals following all treatments.
Previous reports have indicated varying
sensitivity to ethylene among cultivars of
geranium (Clark et al., 2001; Deneke et al.,
1990). Increased rates of abscission over controls
were observed in all cultivars following
1 h of exposure to 1.0 mL·L–1 ethylene. In
geranium, petal abscission rates depend on
both the ethylene concentration and treatment
times (Evensen, 1991).