The effects of methyl jasmonate and salicylic acid on suppressing the production of reactive oxygen species and increasing chilling tolerance in 'Eureka' lemon [Citrus limon (L.) Burm. F.]

Certain markets have phytosanitary requirements which stipulate exposing lemons to temperatures below 0 C during export. Such exposure can result in the development of chilling injury (CI), caused primarily by the accumulation of reactive oxygen species (ROS). The potential of methyl jasmonate (MJ) and/or salicylic acid (SA) to reduce the accumulation of ROS and, hence, the incidence of oxidative damage resulting in CI during cold storage, were investigated. Lemon fruit were dipped in various concentrations of MJ and/or SA, waxed with Citrasbine (R) and stored at -0.5 degrees C for 0, 7, 14, 21, 28, 35, or 42 d before being transferred to room temperature for a simulated 7 d shelf-life period.Treatment with MJ and/or SA significantly (P <= 0.05) lowered CI and membrane lipid peroxidation, suppressed ROS production, and enhanced anti-oxidant activity in the lemon flavedo. However, the effects of MJ and/or SA were concentration-dependent. Treatment with 10 mu M MJ plus 2 mM SA was most effective at enhancing the stability of cell membranes and protected cells from possible damage by ROS. Application(s) of MJ and/or SA should be investigated further as a tool to reduce CI in lemon.