Acomparative study in stem anatomy and morphology of Zannichellia palustris L. and Myriophyllum spicatum L. that growing in Tigris River within Mosul City, Iraq.

Abstract

The current study examined two groups of submerged aquatic plants growing in Tigris River within Mosul city; monocots which represented by Zannichellia palustris and dicots that represented by Myriophyllum spicatum. The results showed variation in some morphological and anatomical characteristic between species, in M. spicatum two types of leaves observed, submersed were solid and strong and divided into more than 14 leaflet pairs, but the emergent leaves (bracts) were inconspicuous and smooth edged, located on the flower spike. While the blade in Z. palustris described as a simple type and linear that thread-like shaped. The results also showed anatomical variation in the internal structure of the stems particular in the area of the cortex. In M. spicatum three layers of parenchyma cells observed after the epidermis, while the epidermis was surrounding the earenchyma directly in Z. palustris. however, the size of earenchyma lacunae were much greater than lacunae of Z. palustris, which also characterize by central cylinder with a central channel surrounded by small parenchyma cells and reduce in xylem tissue, in M. spicatum the central canal was absent but the xylem was presence as solitary vesseles surrounded by parenchymas cells.