The effect of varying levels of ethylene on the chilling injury (CI) development and the changes in the levels of putrescine, squalene and a-farnesene of 'Tahitian' lime (Citrus latgolia Tanaka), 'Emperor' mandarin (Citrus reticulata Blanco), 'Marsh' grapefruit (Citrus paradisi Macf) and 'Valencia' orange (Citrus sinensis L Osbeck) stored at 0°C was investigated. It was found that different citrus fruits stored at 0°C had varying sensitivity to CI, and that low levels of exogenous ethylene induced earlier and more severe CI in all citrus fruits. The levels of endogenous putrescine, squalene and a-farnesene varied between fruit, and was affected by the time of exposure at 0°C and the presence of ethylene. The patterns of change indicate that loss of squalene coupled with loss of afarnesene could be involved in induction of CI.

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Mature but unripe Fuerte and Hass avocados harvested at 3 stages of maturity were vacuum-infiltrated with 4 and 8% calcium chloride (CaCl2) solutions and stored at 20�C. The fruit were assessed for ripening and injury development and analysed for Ca content. Postharvest application of Ca to fruit harvested 2 weeks before prime harvest elicited a greater delay in ripening and caused less fruit injury than application at prime harvest or 2 weeks after prime harvest. Fruit maturity did not have a significant effect on the amount of Ca taken up by fruit when infiltrated with each CaCl2 solution. Vacuum infiltration with 8% CaCl2 solution greatly enhanced the uptake of Ca by both Hass and Fuerte fruit but did not delay ripening further than 4% CaCl2 treatment.