Effects of Abscisic Acid on the Root, Stem and Leaf Anatomy of Radish Seedlings

Abstract

In this work, the effects of various concentrations of abscisic acid on the root, stem and leaf anatomy of radish seedlings were studied. Although the concentrations of abscisic acid mostly decreased the root diameter, cortex zone thickness, endodermis cell length, vascular cylinder diameter, protoxylem and metaxylem width in comparison with roots of control seedlings grown in distilled water medium, they generally increased the root hair number and epidermis cell width. As for the stem anatomy, many of the concentrations stimulated more or less the stem diameter, epidermis cell width and cortex zone thickness while they usually reduced the epidermis cell length, vascular bundle width and trachea diameter. On the other hand, the concentrations used mostly
increased the stomata number in the lower surface, stomata length in the upper surface and stomata index in both surfaces, whereas they generally decreased the epidermis cell number in the upper surface, stomata width and lenght in the lower surface, epidermis cell width in both surfaces, leaf thickness and distance between vascular bundles.