Morpho-histogenic studies in the pericarp of Cardiospermum halicacabum L. (Sapindaceae)

Abstract

The present study deals with the ontogeny, structure and development of Cardiospermum halicacabum fruit and the mode of its dehiscence. The trigonous, pyriform and bladdery capsular fruit of C. halicacabum develops from a 3-celled ovary with one ovule in each cell. The ovary wall is 5 to 7 cell layers thick. The outer epidermis of the ovary wall develops into a single-layered epicarp. The isodiametric cells of developing epicarp contain abundant tanniniferous contents. The 3 or 4 layers thick ground parenchyma of ovary wall constitutes the mesocarp. The thin walled cells of developing mesocarp are found to get apart from each other, as their elongation is meagre, to keep pace with the increment in the circumference of fruit. The tangentially elongated cells of inner epidermis of ovary wall form a single layered endocarp. The endocarpic cells of developing fruit do not exhibit much structural changes, except vacuolation. Due to the disintegration of thin walled parenchyma cells situated throughout the length of the septum and rupture of similar type of cells located in between two lateral vascular bundles, the ripe capsule of C. halicacabum dehisces septicidally.