Abstract
The structure of hydathode in the leaf tip of indoor-grown and outdoor-grown rice plants was examined by light and transmission electron microscopy. Terminal ends of large-sized vessel elements are in direct contact with some cells of the epidermis covering the extreme tips of. the leaves. Expanded intercellular spaces directly adjoin thin cell wall of the large vessel elements. The cell wall of vessel elements exhibited a secondary thickness in places. Intercellular spaces are occasionally occupied with numerous bacteria. Mesophyll parenchyma cells surrounding the vessel elements characteristically have cell wall ingrowths developed slightly. The mesophyll cells sometimes contain electron dense deposits which are tightly packed between cell wall and plasmamembrane. Microbodies are often present in the mesophyll cells. From these results, it was elucidated that rice leaf hydathode principally consists of large-sized vessel elements, the adjoining expanded intercellular spaces and water pores.
