Impact of postharvest prohexadione calcium treatment on PAL activity in tomato fruit in response to chilling stress. Norali Ghiasi 1* and Farhang Razavi 2

Abstract

<span style="font-family: Calibri;"><span style="font-size: medium;"><span>Freshly harvested tomato fruit </span><span>(<em>Solanum</em> <em>lycopersicum</em>) </span><span>were pre-treated with </span><span>0, 50, and 100 µM prohexadione-calcium (Pro-Ca) </span><span>and then stored at 1 °C for 21 days to investigate the effect of </span><span>Pro-Ca</span><span> treatment on </span><span>electrolyte leakage (EL), malondialdehyde (MDA), proline and total phenols contents, and activity of phenylalanine ammonia-lyase (PAL)</span><span> in relation to chilling injury (CI).</span><span>Treatment with Pro-Ca, without significant difference between two applied concentrations, mitigated chilling injury, reduced EL and MDA content and increased proline content. Also, our results indicated that during </span><span>storage time</span><span> fruits treated with Pro-Ca exhibited significantly higher PAL activity, but total phenols content was not significantly affected by Pro-Ca treatments. These results suggested that Pro-Ca protects tomato fruit from CI by activation of PAL enzyme, enhancing proline contents and reducing MDA content, and </span><span>thus maintaining membrane integrity</span><span>.</span></span></span> <span><span style="font-family: Calibri; font-size: medium;"> </span></span>