Structural Design of the Developing Fruit Walls of Brassica juncea (L.) Czern. and Raphanus sativus L.

Abstract

The exocarp of B. juncea and R. sativus is the outermost layer of the pericarp; the 12–14 cells thick mesocarp develops from the histologically homogenous 6 – 9 cells thick ovary wall and the single layered endocarp develops from the innermost layer of the ovary wall - the inner epidermis. About 10–13 sclerenchyma of the inner hypodermis in Brassica and 4–7 such selenchyma in Raphanus coincide with each endocarpic cell. The stomata are frequent on the exocarp but the endo carp is astomatic. The vascular bundles in Brassica are sclerosed but feebly developed in Raphanus . The dehiscing zones of Brassica fruit become distinct as narrow band of parenchyma inbetween the lignified eells of the mesocarp near ventral vascular bundles. The mature mesocarpic parenchyma are stretched in two directions. In the beak region of Brassica; where there are no dehiscing zones, because of the absence of sclerenchymatic inner hypodermis, and thining of the veins later the two dry valves fall off from the tip. Raphanus has no zones of dehiscence from base to the tip and the valves do not separate