Effect of Bolting on Postharvest Chlorophyll Degradation of Japanese Radishes

Abstract

The rapidity of post-harvest chlorophyll degradation in three Japanese radish cvs. Hayabutori-tokinashi, Houryou and Soubutori-miyashige was studied. Seeds were sown on 10 May and the first harvest occurred on 19 June when half of the 'Soubutori-miyashige' plants had bolted. The bolted plants and the non-bolted plants of 'Hayabutori-tokinashi' and 'Houryou' were harvested and kept at 20°C. On 4 July when half of the 'Houryou' plants began to bolt, both the bolted and non-bolted plants and non-bolted 'Hayabutori-tokinashi' plants were harvested and stored at 20°C. At harvest and 3 days later, leaves at different positions were analyzed for chlorophyll content.
1. Leaf chlorophyll level decreased more rapidity 3 days after storage in plants harvested on 4 July than it did in those harvested on 19 June. The degradation took place more rapidly in lower than it did in upper leaves; the pace was accelerated on bolted plants.
2. The respiration rate of bolted plants in the dark was slightly higher than that from non-bolted ones. The rate of ethylene evolution of 'Hayabutori-tokinashi' plants was the fastest. There is no correlation between the rates of ethylene evolution and chlorophyll degradation.