Ms. Tian et al., EFFECTS OF FLORET MATURITY, CYTOKININ AND ETHYLENE ON BROCCOLI YELLOWING AFTER HARVEST, Postharvest biology and technology, 6(1-2), 1995, pp. 29-40
The phytohormones ethylene and cytokinin have a central role in the po
stharvest yellowing of broccoli. The relationship between ethylene syn
thesis and the extent of yellowing was examined in three broccoli cult
ivars ('Shogun','Green Belt' and 'Green Beauty'). In these cultivars,
no consistent relationship was found between basal ethylene production
and the rate of floret degreening (20 degrees C in darkness). In cult
ivar 'Shogun', floret maturity stages were determined by examining the
developmental stages of the pollen. Different patterns of ethylene pr
oduction, ethylene sensitivity, respiratory activity and chlorophyll l
oss occurred in florets of different maturities. Floret maturity is li
kely to have the greatest effect on the rate of broccoli yellowing. Di
pping florets (cv. 'Shogun') in 6-benzylaminopurine (6-BA) stimulated
ethylene production, depressed respiration rate and delayed floret yel
lowing. The effect of cytokinin on broccoli yellowing was related to c
ytokinin concentration and postharvest floret age when the cytokinin w
as applied. A continuous propylene treatment reduced the positive effe
ct of cytokinin on broccoli colour changes.