EFFECT OF METHYL JASMONATE AND SALICYLIC ACID ON CHILLING INJURY OF 'EUREKA' LEMONS

X.I. Siboza, J.P. Bower, I. Bertling
Lemons are susceptible to chilling injury when exposed to temperatures below -0.5°C. South Africa produces and exports lemons to countries around the world. The industry continues to lose large amounts of fruit to chilling injury during postharvest storage. Exposing lemons to low temperature (-0.5°C) for a certain period is an obligatory quarantine treatment for disinfestations of Mediterranean fruit fly. However, fruit do not tolerate such temperatures and develop chilling injury - an unsolved problem in the citrus industry. As postharvest applications of methyl jasmonate and salicylic acid have been successfully used in mangoes, guavas and peaches to reduce symptoms of chilling injury. A similar treatment was applied to ‘Eureka’ lemons. Fruit were sterilized, air-dried and dipped in 1, 10 or 50 µM of methyl jasmonate or 1, 2 or 2.5 mM of salicylic acid for 30 s, waxed with Avoshine® and stored at -0.5°C for 0, 7, 14, 21, 28, 35, or 42 days, before being transferred to ambient temperature for 7 days. Measurements of fruit weight, ethylene and CO2 evolution, electrolyte leakage of the rind, total antioxidant capacity/activity, total phenolics and soluble sugars were taken. Fruit did not develop visual symptoms of chilling injury despite the extended cold storage time. No significant differences (P>0.05) were found between treatments and cold storage time with respect to electrolyte leakage, ethylene evolution and respiration. However, treatment with 10 µM methyl jasmonate or 2 mM salicylic acid significantly (P<0.05) reduced fruit mass loss and slowed reduction of total antioxidants during cold storage. Therefore, methyl jasmonate and salicylic acid dips can enhance the resistance of fruit to chilling injury probably through an increase in antioxidant levels.
Siboza, X.I., Bower, J.P. and Bertling, I. (2011). EFFECT OF METHYL JASMONATE AND SALICYLIC ACID ON CHILLING INJURY OF 'EUREKA' LEMONS. Acta Hortic. 911, 409-414
DOI: 10.17660/ActaHortic.2011.911.47
https://doi.org/10.17660/ActaHortic.2011.911.47
chilling injury, methyl jasmonate, salicylic acid, antioxidants
English

Acta Horticulturae