OXIDATIVE STRESS, ANTIOXIDANT CAPACITY AND ETHYLENE PRODUCTION DURINGAGING OF CUT CARNATION (DIANTHUS-CARYOPHYLLUS) PETALS

The objective of this work was to study the role of free radicals in r elation to ethylene production during ageing of cut carnation petals, Ethylene production by freshly cut flowers was negligible, but 8 d aft er cutting ethylene production began to increase and reached a peak by day 9, before beginning to decline again, The efflux of electrolytes (membrane damage index) increased 101% and 2',7'-dichlorofluorescein o xidation rate (oxidative stress index) increased 53% from day 8 to day 11 after detachment, Ethylene peak was either (a) not affected signif icantly by the supplementation of exogenous ethylene on the day of cut ting, or (b) expanded between days 7-9 after ethylene supplementation on day 6 of cutting, or (c) was inhibited by amino-oxyacetic acid and paraquat treatments, After ethylene supplementation, conductivity and 2',7'-dichlorofluorescein oxidation increased significantly as compare d to control petals, and the activity of antioxidant enzymes was not a ffected, However, both cr-tocopherol and glutathione content decreased significantly after ethylene supplementation on day 6 after detachmen t, Amino-oxyacetic acid treatment prevented the increases in conductiv ity and 2',7'-dichlorofluorescein oxidation, did not alter the activit ies of antioxidant enzymes and significantly increased the content of alpha-tocopherol and glutathione as compared to control carnation peta ls, Paraquat treatment paralleled qualitatively ethylene supplementati on after 6 d of cutting.