CO2 treatment of zucchini squash reduces chilling-induced physiological changes

Zucchini squash showed chilling injury (CI) damage as pitting on 93% of their surface after 12 days at 2 degrees C, and a 2-2.5-fold increase in putrescine levels in both skin and pulp was detected during storage (from 162 and 38 to 320 and 98 nmol g(-1) of fresh weight, respectively). Abscisic acid concentration increased mainly in the skin. Treatments with CO2 prior to storage at 2 degrees C were found to be effective in reducing CI. With 5% CO2, increases in putrescine and abscisic acid levels were lower than in control fruits, while exposure to 40% CO2 resulted in a decrease of these values. Spermidine and spermine levels decreased during storage, regardless of treatment. Thus, the 40%, CO2 treatment was more effective than the 5% CO2 one in reducing both CI and the putrescine and abscisic acid changes found in control chilling-injured squash.