Characteristics of Root Caps in Four Root Types of Avicennia marina (Forsk.) Vierh.

Abstract

The anatomy of the root caps in four root types of Avicennia marina were studied using conventional histological tech-niques by Ligth Microscopy (LM) in order to relate their development and structure of their function as environmental adaptation in mangrove's root and to identify cellular polarities with respect to gravity. In columella cells, nuclei are located proximally. The result reveals that root caps consisted of two regions, i.e., central columella or statenchyma and peripheral regions. The columella cells (statocyte) are in the form of oval to rectangular. We also found that all root with marked gravitropism have statoliths that settle along different walls of that statocyte. Caps vary in form and size within root system of A. marina. The most striking feature of the root is the distinct and extensive root cap with quite long files of cells. From its shape, structure, and location, it seems clear that the root caps protects the cells under it from abrasion and assists the root in penetrating the soil.