Structure and Development of Pod of Calliandra tweedii Benth.

Abstract

Summary The mature pericarp is differentiated into one layered thick walled epicarp, 10—12 layerd valvular mesocarp, 15—20 layered sutural mesocarp and 6—8 layered endocarp. The outer 3—4 layers of valvular mesocarp are sclerotic, composed of sclereids. In sutural mesocarp, but for 3—5 hypodermal layers, all layers outside vascular bundles become sclerenchymatous. This selerenchyma zone is separated into 5—7 segments by radial rows of 1—2-celled wide parenchymarays. Endocarp lining the seed chamber is sclerenchymatous, the cells of the innermost two layers are tangentially elongated, whereas those of the outer layers are radially elongated. Inner epidermis forms an interseed region. Sutural vascular bundles are 5—6 on either side of the groove in the dorsal and ventral sutures. valvular vascular bundles are 10—15 in each valve, but they are smaller and less differentiated than sutural bundles. the pericarpial anatomical structure is “Acacia type”. The dehiscence is from tip to base along sutures. The mature basal region is characterised by a rich tanniniferous zone of thin walled epidermis and 3—5 layers of hypodermis. The secondary growth is observed even in earliest stages of pod development. The central cylinder breaks into two groups, each of 13—15 segments, due to lateral constriction of the parenchyma. These separate and later establish as dorsal and sutural bundles. Each bundle is with a multicellular hemispheric or C-shaped sclerenehymatous zone. The inner epidermis and 2—3 layers outside it constitute endocarp. The apical region at its extremity consists of one layered epidermis, some cells with tannin, 8—10 layered parenchymatous cortex and poorly developed sutural vascular bundles and sclerenchyma.