Abstract
Experiments were designed to clarify a role of calyx for occurring the blossom-end rot (BER) in tomatoes by regulating transpiration and Ca transport. Fruit cluster in an early stage of fruit development was treated with or without calyx lobes in combination with airflow or bagging with aluminum foil. The incidence of BER was increased by the bagging of fruits or the removing of calyx lobes, especially in summer as compared with winter culture. The incidence of BER was considerably reduced by the air flowing to fruits. In the absence of calyx lobes or in the fruit truss enclosed by bag in the early stage of fruit development, fruits were dropped or their development was greatly arrested, especially in summer, whereas their development was considerably promoted in winter. The effect of these treatments in the early stage (from 0 to 20 days after blooming) of fruit development was greater than that in the later stage (from 40 to 60 days after blooming) of fruit development. The percentages of dry matter of tomato fruit or calyx were reduced by the bagging of fruits. The Ca contents in fruit were decreased, and K and N contents in fruit were increased with the increase of BER incidence, especially at the distal end of fruit as compared with the basal part of fruit. The ratios of K/Ca, N/Ca, P/Ca and Mg/Ca in fruit were high in fruit with severe BER. Conclusively, the incidence of BER in fruit was promoted by the inhibition of transpiration of fruits without calyx or with bagging, whereas that was considerably reduced by air flow to fruit or calyx of tomato in the early stage of fruit development.
