Abstract

Chilling-sensitive fruit often produce a burst of ethylene when reconditioned at ambient temperature after cold storage. This has led some authors to propose that Chilling injury (CI) may be induced by post-chilling ethylene production. To test this hypothesis we examined two tomato (Solanum lycopersicum L.) mutants, non-ripening (nor) and ripening-inhibitor (rin) that do not produce climacteric ethylene. Fruits were stored at 5°C followed by reconditioning at 20°C, during which time a detailed characterisation of respiration, ethylene production, colour analysis, firmness, total soluble solids, starch content and weight loss was done. The response of the mutants to cold-storage at 5°C differed, and was not as extreme as the parent line cv. Ailsa Craig, still, both mutants showed symptoms of chilling stress on the ripening pathways that are initiated upstream of climacteric ethylene production. When the fruit were stored at 2°C for 14 days followed by reconditioning at 20°C for 3 weeks, visual evidence of CI such as water-soaking, non-uniform ripening and minimal colour change was noted in both the control and mutant genotypes. We conclude therefore that while ethylene production may influence chilling injury, it is not essential for initiating this process in tomato cv. Ailsa Craig.

Key words: Chilling injury, tomato fruit, ripening mutants, rin, nor.