Mitigation of postharvest chilling injury in tomato fruit by prohexadione calcium

Storage of tomato (Solanum lycopersicum) as originally tropical fruit is limited by the risk of chilling injury (CI). To develop an effective technique to reduce CI, the effects of treatment with 0, 50 and 100 mu M prohexadione-calcium (Pro-Ca) on CI, electrolyte leakage (EL), malondialdehyde (MDA) and proline contents, and activities of phospholipase D (PLD) and lipoxygenase (LOX), were investigated in tomato fruit stored at 1A degrees C for 21 days. Treatment with Pro-Ca, without significant difference between two applied concentrations, significantly mitigated chilling injury. Also, Pro-Ca treatment maintained lower levels of EL and MDA content, higher level of proline content and inhibited the increases in PLD and LOX activities compared with the control fruit. These results suggest that Pro-Ca might mitigate CI by inhibiting PLD and LOX activities and by enhancing membrane integrity.