The morphology of red bayberry (Myrica rubra Sieb. et Zucc.) during fruit development

The changes in morphology and anatomy during fruit development in red bayberry (Myrica rubra Sieb. et Zucc.) were examined in Japan. The edible portion of red bayberry is a juice column, compared with the juice sac in citrus. Juice columns are initiated as bulges on the epidermal side of the exocarp, and have condensed cytoplasm and large nuclei. Primordia developed continuously from anthesis on 22 April to 6 May, although some columns appeared before anthesis. The length of the juice column increased markedly from 2.9 mm on 10 June, to 7.6 mm. on 1 July, corresponding to the increase in fruit diameter. At harvest, the juice column extended to approx. 65% of the fruit diameter. A vascular bundle entered each juice column and was connected to the mesocarp. A cap on the top of the column was initiated early in the development of the column and persisted until maturity. Several small glands also developed on the side of each juice column. These glands may act on a protection from insect damage, because the glands generally contain resin.