Ethylene involvement in chilling injury symptoms of avocado during cold storage

Application of exogenous ethylene, irrespective of the method of application, caused intensification of mesocarp discoloration in avocado fruit (Persea americana Mill.) during cold storage of all cultivars tested. 'Ettinger' fruit treated with Ethrel (2-chloroethyl phosphonic acid) prior to packing and storage developed severe chilling injury (CI) symptoms, expressed as mesocarp discoloration after 3 weeks at 5degreesC. 'Fuerte' fruit treated with ethylene gas (100 mul l(-1)) for 24 h at 20degreesC prior to storage at 5degreesC exhibited mesocarp discoloration, which increased dramatically during shelf life at 20degreesC. 'Fuerte' Fruit treated in cold storage with a continuous low ethylene dose (4 mul l(-1)) developed severe browning in the fruit pulp after 3 weeks at 5degreesC. 'Hass' fruit treated with 50 mul l(-1) ethylene, for 12, 24 or 48 h at 5degreesC showed a gradual increase in mesocarp discoloration after 3 weeks in cold storage plus shelf life; the 48 h ethylene-treated fruit exhibited the most severe pulp browning. Use of absorbent sachets that removed ethylene from modified atmosphere (MA) packaging reduced mesocarp discoloration and decay development in 'Hass' fruit after 5 weeks storage at 5degreesC. Application of 1-methylcyclopropene (1-MCP), reduced mesocarp discoloration, decay development and polyphenol oxidase activity, whereas this enzyme activity was induced in ethylene-treated fruits that were cold stored for 4 weeks. (C) 2002 Elsevier Science B.V. All rights reserved.