Inhibition of postharvest decay of fruits by nitrous oxide

Nitrous oxide (N2O) was tested for its potential to control the postharvest decay of fruits. Both climacteric and non-climacteric fruits were inoculated with high and low N2O-sensitive groups of Fungi. Fruits included apple cv. Fuji, inoculated with Alternaria alternata and Penicillium expansum, strawberries cv. Toyonoka with Botrytis cinerea, Fusarium oxysporum f. sp. fragariae and Rhizopus stolonifer, Satsuma mandarin with Geotrichum candidum, tomato cv. Momotaro with F. oxysporum f. sp. lycopersici, persimmon cv. Fuyu with Colletotrichum acutatum and seedling guava with R. stolonifer. Inoculated fruits were exposed to 80:20% (N2O:O-2) and stored at 20 degreesC. In addition, strawberries were inoculated with B. cinerea and exposed to 10, 30, 50 and 80% N2O with 20% O-2 and stored at 2 degreesC. Our results showed that regardless of the physiological nature of the fruits or group of fungi, N2O delayed the appearance of disease and reduced the lesion growth rate. This response to N2O was dose and time dependent. This suppression of decay by N2O treatment is thought to be a direct inhibitory effect on fungal growth rate and/or increased resistance of host tissue. (C) 2001 Elsevier Science B.V. All rights reserved.