Postharvest jasmonic acid and methyl jasmonate dip treatments alleviate chilling injury and maintain quality of cold-stored 'Black Amber' and 'Tegan Blue' Japanese plums (Prunus salicina Lindell).

Background: Chilling injury (CI) in Japanese plums (Prunus salicina Lindell) is a critical cold storage constraint that adversely impacts fruit quality and marketability. Jasmonic acid (JA) and its methyl derivative 'methyl jasmonate' (MeJA) are widely studied phytohormones for the mitigation of CI in several fruit crops, whereas their efficacy in Japanese plums remains unexplored. Freshly harvested 'Black Amber' and 'Tegan Blue' plums were dipped for 1 min in 0 (control), 25, 75 or 250 ppm of aqueous solutions/emulsion of jasmonic acid (JA), methyl jasmonate' (MeJA) and the ethylene precursor aminocyclopropane-1-carboxylic acid (ACC), and cold stored for 14 and 28 days followed by 1 and 2 days under shelf conditions. Fruits were evaluated for CI incidence, CI index, relative electrolyte leakage (REL) and other physicochemical quality attributes.

Results: JA and MeJA treatments significantly reduced CI in both cultivars. In 'Black Amber' plums, MeJA 250 ppm decreased CI incidence to 16.6% compared to control (56.7%). In 'Tegan Blue' plums, 250 ppm JA and 25 ppm MeJA lowered CI incidence to 35% compared to 81.7% in control. REL was significantly reduced in JA and MeJA treatments. The flesh firmness remained higher in 'Tegan Blue' plums treated with all three concentrations of MeJA dip treatment. The soluble solids content (SSC) and SSC:titratable acidity (TA) ratio was significantly increased in 'Black Amber' plums dipped in an aqueous solution of ACC (250 ppm). The percentage of TA was not significantly affected by JA, MeJA and ACC treatments.

Conclusion: This is the first study to show that the application of MeJA and to a lesser extent JA alleviated CI in both cultivars of plum fruit without compromising fruit quality. © 2025 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.