EUREKA LEMON CHILLING INJURY

In accordance with the currently approved Australian citrus disinfesta tion protocol for export to Japan, degreened 'Eureka' lemons [Citrus l imon (L,) Burm,] were cold-stored for 2 weeks at 1C. Following cold tr eatment, fruit were stored at 5C for 3 weeks, then transferred to 20C for an additional week to simulate transportation and handling. Fruit harvested early in the season were more susceptible to chilling injury than fruit harvested later, with 62% having lesions >1 cm(2) after 2 weeks at 1C. Most of the chilling injury occurred after subsequent sto rage (at 5C) rather than immediately after the 1C treatment, Injury wa s different from surface pitting or oleocellosis, manifesting as large uniform surface lesions 2 to 3 cm in diameter that rapidly discolored following storage at 20C, Although the oil glands were flattened, the collenchyma layer immediately above the oil gland remained intact, Ce llular discoloration was localized around the oil gland, possibly indi cating a lateral release of oil gland contents. Nondegreened late-seas on fruit developed substantially lower levels of chilling injury.