VESSELS IN THE ROOTS OF BARCLAYA ROTUNDIFOLIA (NYMPHAEACEAE)

Scanning electron microscope (SEM) studies of paraffin-sectioned material of stems and roots of Barclaya rotundifolia Hotta revealed perforations on tracheary elements of roots, but not on those of stems. End walls of vessels are identical with lateral walls except for the presence of perforations. Perforations can only be clearly revealed with SEM, and this method is advocated for further study of tracheary elements of Nymphaeaceae in particular, and primary xylem of angiosperms in general. Vessel presence may be related to the habitat of this species, which unlike other members of the Nymphaeaceae (sensu stricto) has only aerial leaves and a rhizomatous system that is not inundated for prolonged periods.