Comparative Study of Two Grasses from Different Habitats by Scanning Electron Microscopy

Abstract

A scanning electron microscope comparative study was carried out on root, stem and leaf structures of Ammophila arenaria (L.) Link. and Phragmites australis (Cav.) Trin. ex Steud. These perennial grasses are characteristic of seashore sand dunes and aquatic environments, respectively. The structures of the organs referred to above are similar in both species, nevertheless each exhibits adaptive characters to its habitat. A. arenaria shows some adaptations to the dry conditions of its habitat, mainly in the leaves. Hence the stomata are found in furrows situated on the adaxial surface and protected from the surrounding environment by the leaf rolling up. The presence of broad bands of sclerenchyma in root and stem, and to a less extent in leaves, was observed in this species. In P. australis the presence of aerenchyma in the root and stem was an evident adaptation to its aquatic environment. This tissue permits gas diffusion among the submerged parts of the plant. The rhizomes of this species store considerable amounts of starch which was observed as grains in the parenchymatous cells of the cortex.