บทคัดย่องานวิจัย

หมวดหมู่ : ฐานข้อมูลงานวิจัย

Temperature and ethylene affect induction of rapid softening in ‘Granny Smith’ and ‘Pacific RoseTM’ apple cultivars.

Johnston, J. W., Hewett, E. W., Hertog, M. L. A. T. M. and Harker, F. R.

Postharvest Biology and Technology, Volume 25, Number 3, July 2002 , pp. 257-264

2002

บทคัดย่อ

Temperature and ethylene affect induction of rapid softening in 'Granny Smith' and 'Pacific RoseTM' apple cultivars.

The occurrence of rapid softening in apples (Malus domestica [M. pumila]) at ambient temperatures (10-20 deg C) varies among cultivars, as some cultivars require exposure to low temperatures before autocatalytic ethylene biosynthesis occurs. The influence of time at 0.5 deg C on subsequent softening at 20 deg C was investigated for the slow softening 'Granny Smith' and 'Pacific Rose' apple cultivars (harvested from Palmerston North, New Zealand). Ethylene (100 micro litre litre-1 for 24 h) was also applied to apples at 20 deg C to determine if ethylene treatment could replace the requirement for cold treatment. 'Granny Smith' fruits without ethylene or cold treatment softened slowly at 20 deg C, while both ethylene- and cold-treated fruits softened more rapidly than nontreated fruits. Nontreated 'Pacific Rose' fruits also softened slowly or not at all at 20 deg C, but in contrast to 'Granny Smith', did not soften rapidly after either ethylene or cold treatment. The mechanism by which both cold and ethylene treatments initiated rapid softening in 'Granny Smith' may be facilitated by ethylene, as these treatments induced maximum internal ethylene concentrations (IEC) that were two to threefold greater than in nontreated fruits at 20 deg C. However, rapid softening at 20 deg C was often delayed relative to the increase in IEC from basal concentrations for cold-treated 'Granny Smith' fruits. This delay for cold-treated 'Granny Smith' fruits, and absence of rapid softening in 'Pacific Rose' fruit at 20 deg C despite a maximum IEC of more than 100 micro litre litre-1, suggests that fruit sensitivity to ethylene may be more important than IEC for regulating softening. 'Pacific Rose' may be a genotype of apple with reduced capacity for ethylene biosynthesis and action, and hence softening. The role of ethylene in softening of both cultivars at shelf life temperatures may be clarified by research on changes in ethylene sensitivity that occur during maturation and ripening.