Chilling injury in mango fruit in relation to biosynthesis of free polyamines.
Suresh Nair, Zora Singh
Author Affiliation: Horticulture/Viticulture, Muresk Institute, Division of Resources and Environment, Curtin University of Technology, GPO Box U1987, Perth, WA 6845, Australia.
Journal of Horticultural Science and Biotechnology 79 : 515-522
Abstract : Mature green mango (cv. Kensington Pride) fruits were stored at 0, 5, 10, 15 and 20°C for 1, 3, 7, 14, 21 and 28 days in 1999 to induce different levels of chilling injury (CI) and to investigate its relationship with endogenous polyamines during storage. In a related experiment conducted in 2000, the fruits were stored at 5 and 15°C for 2 weeks and were allowed to ripen at 22±1°C to determine the relationship between endogenous free polyamines and CI during ripening. The fruit CI index increased as the storage temperature was decreased from 10 to 0°C and the storage period was prolonged from 1 to 28 days. The CI symptoms progressed during the ripening period in fruits stored at 5°C for 2 weeks. The total free polyamines in the skin and pulp were higher in the chill-injured fruits than in the non-chill-injured fruits during storage and ripening except on day 4 of the ripening period. The accumulation of putrescine and the depletion of spermidine and spermine in the skin and pulp of the chill-injured fruits were recorded during the storage and ripening periods. In another experiment in 2000, the exogenous application of spermine (0.50 mM) effectively reduced CI, among the different concentrations of the 3 polyamines tested. Putrescine accumulation did not inhibit CI in mango fruits but the chilling stress promoted its accumulation in the early stages of ripening. The depletion of endogenous spermidine and spermine with CI and the reduction of CI with pre-storage application of these polyamines indicate that CI development in mango fruit is associated with the biosynthesis of polyamines.