Alleviation of chilling injury induced by cold quarantine treatment in Midknight Valencia and Lane Late sweet orange fruit

Abstract

Cold quarantine treatment (1°C for 21 days) induces chilling injury (CI) in sweet orange fruit. We investigated the effects of different treatments such as hot water dip (HWD, 50 °C) alone or combined with thiabendazole (TBZ) five-minute, different concentrations of salicylic acid (SA), methyl jasmonate (MJ) one-minute dip and fumigation of nitric oxide (NO) two-hour and ethylene (ET) (six-hour) on CI and fruit quality following 21 days cold quarantine treatment and 10-day at ambient temperature in 'Lane Late' and 'Midknight Valencia' fruit. The experiment was laid out by following completely randomised design included three replications. HWD alone or combined with TBZ, or MJ significantly reduced CI in both cultivars. NO (5 μL L-1) fumigation significantly reduced weight loss in 'Lane Late' only as compared to all other treatments except SA (1, and 3 mM). SCC/TA ratio was significantly reduced with ethylene, HW alone or combined with TBZ or MJ (0.25 mM) as compared to all other treatments in 'Midknight Valencia', but not in 'Lane Late'. The NO (10 μL L-1) fumigation resulted in the significantly highest level of vitamin C only in 'Midknight Valencia'. SA (3 mM) dip treatment resulted in the significantly highest levels of total antioxidants as compared to all other treatments in 'Lane Late' but not in 'Midknight Valencia'. In conclusion, HWD alone or in combination with TBZ (20 mg L-1) or MJ (0.50 mM) effectively reduced CI caused after cold quarantine treatment without adversely affecting fruit quality.

Susceptibility of Blood Orange Cultivars to Chilling Injury Based on Antioxidant System and Physiological and Biochemical Responses at Different Storage Temperatures

“…PAL activity has been considered as a defence mechanism of cold stored fruit in response to chilling stress [8,28,33]. Cold temperature can enhance PAL activity in blood orange by upregulating PAL codifying genes in response to chilling stress [9]. In this sense, PAL mRNA accumulated in mandarin fruit during storage at low temperature (2 • C), which was related to the sensitivity of citrus fruit to CI [34].…”

“…The common responses include changes in cell structure, fatty acid saturation index, lipid peroxidation, electrolyte leakage (EL), proline content, hydrogen peroxide (H 2 O 2 ), malondialdehyde (MDA), activity of antioxidant enzymes and epidermis structure, among others [8]. In addition, chilling stress can change the cellular metabolism and reduce cell energy status, leading to chilling injury (CI) symptoms such as scalding, rind pitting and necrotic areas, watery breakdown and browning [8,9]. Postharvest treatment by hot water dipping (HWD, 3 min at 50 • C) and hot air treatment (HAT, 37 • C for 48 h) on blood orange fruit during cold quarantine at 1 • C for 16 days, showed that HWD and HAT similarly reduced CI in all cultivars, and neither treatment caused visible damage to the fruit [10].…”

Susceptibility of Blood Orange Cultivars to Chilling Injury Based on Antioxidant System, Physiological and Biochemical Responses at Different Storage Temperatures

“…The common responses include changes in cell structure, fatty acid saturation index, lipid peroxidation, electrolyte leakage (EL), proline content, hydrogen peroxide (H2O2), malondialdehyde (MDA), activity of antioxidant enzymes and epidermis structure, among others. In addition, chilling stress can change the cellular metabolism and reduce cell energy status and leading to chilling injury (CI) symptoms such scalding, rind pitting and necrotic areas, watery breakdown, and browning [8][9][10].…”