Anatomical and Histological Changes of the Pulp Tissue in Developing Akebi (Akebia pentaphylla) Fruit

摘要

The growth of akebi (Akebia pentaphylla) fruits was investigated to analyze the edible portion of the fruit in relation to its cell structure throughout the fruit growing period. Samples ranging from flowers to mature fruits were collected weekly frommature trees. Hie growing period from anthesis to fruit maturity lasted 24 weeks. The flesh of akebi fruit arose as projections from the placenta derived from the endocarp just before and at flowering. During the fruit growing period, the expansion of the pulp tissue was observed as placentation. The tip of the protrusion of the pulp tissue continued to erupt with a volcano-like appearance, and functioned as meristematic tissue. The contact interface at the tip portion of the pulp tissues fused with each other. Finally, the pulp tissues filled the entire carpel and packed many seeds. At fruit maturity, a crevice between the basal part of pulp tissue and rind appeared, and then the rind dehisced along the ventral suture.