Chilling injuri as related to climacteric behaviour in plums

Abstract

Plums have a limited postharvest life due to their elevated rate of ripening and because they can develop chilling injury after long cold storage, even when stored at optimal temperatures (0°C ± 0.5°C). Flesh browning and flesh translucency are the main symptoms and the susceptibility depends on the cultivar and storage temperature (Crisosto et al. 1999). Flesh browning is a brown discolouration of the flesh that starts below the epidermis. Flesh translucency manifests as a translucent gelatinous breakdown of the mesocarp tissue around the stone. Although these symptoms mainly develop during shelf life following cold storage, changes in membrane permeability have been observed before the occurrence of symptoms. These changes in membrane permeability were associated with the development of chilling injury in ‘Songold’ plums (Taylor et al. 1993).

In climacteric fruits, ethylene production at the onset of ripening controls the changes in colour, aroma, texture, flavour and other biochemical and physiological attributes. In contrast, the ripening of non-climacteric fruits is considered as an ethylene-independent process (Lelièvre et al. 1997). Plum cultivars can be classified into climacteric or suppressed climacteric according to their ripening behaviour. Suppressed climacteric phenotype results from an inability of the fruit to produce enough ethylene to coordinate ripening (Abdi et al. 1997). Many trials have been carried out to study the relationship between ethylene production, ripening and ethylene inhibitors such as 1-MCP in plums (Martínez-Romero et al. 2003; Candan et al. 2006). However, further studies are necessary to explain the role that ethylene plays in the occurrence of chilling injury in plums.