Abstract: The effects of calcium (CaCl2) and calmodulin antagonist trifluoperazin (TFP) dipping treatments on chilling tolerance of postharvest peach fruit (Prunus persica Batsch ‘Baifeng’) during cold storage were investigated with distilled water as control. The results showed that CaCl2 treatment could significantly reduce internal browning of peach fruit during cold storage, mitigate chilling injury, decrease relative electric conductivity and malonaldehyde (MDA) content, reduce hydrogen peroxide (H2O2) content and superoxide anion radical (O2 -·) production rate, and the activity of proline dehydrogenase (PDH). In addition, CaCl2 treatment improved the activities of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), Δ1-pyrroline-5-carboxylate synthetase (P5CS), ornithine δ-aminotransferase peroxidase (OAT) and glutathione reductase (GR). High levels of proline, vitamin C and glutathione (GSH) were also observed in peach fruit treated with CaCl2. However, the opposite effect was observed with TFP treatment. These findings suggested that the Ca2+-CaM complex was involved in the regulation of cold tolerance in postharvest peach fruit and that CaCl2 treatment could maintain reactive oxygen metabolism balance, alleviate lipid peroxidation and membrane damage, and increase the accumulation of the osmoregulator proline, thereby reducing chilling injury, maintaining fruit quality and extending the storage life of peach fruits during cold storage.

Key words: calcium, trifluoperazin, peach fruit, chilling injury, chilling tolerance