Temperature effects on uptake and effectiveness of glyoxal dioxime in oranges citrus sinensis cultivar hamlin
Evensen, K.B.; Bausher, M.G.; Biggs, R.H.
HortScience 17(4): 675-676
Temperature effects on glyoxal dioxime (Pik-0ff) stimulation of ethylene production and fruit loosening and on uptake of 14C-glyoxal dioxime were investigated using 'Hamlin' oranges [C. sinensis (L.) Osb.] harvested with petioles attached. Oranges treated with 250 ppm glyoxal dioxime produced significantly more ethylene than untreated fruit at 20, 25 and 30.degree. C but not at 10 or 15.degree. Fruit loosening was correlated with internal ethylene concentration, producing a significant loosening effect for glyoxal dioxime at 20, 25 and 30.degree. Lack of effectiveness of glyoxal dioxime for inducing fruit loosening at low temperatures (10 and 15.degree.) cannot be explained by a reduced rate of uptake but may result from impairment of ethylene biogenesis by fruit tissue.