Abstract
Two types of the characteristic vessel elements were found by the authors in the terminal part of leaf margins (Fig. 2 B) and in the tip of midrib (Fig. 4 A). The shape of both was like a barrel and the diameters were much larger than the normal vessel elements (Fig. 2 A). The lateral wall of the former showed a tendency of increased pitting (Fig. 3 B) as compared with the normal (Fig. 3 A), and the latter, which were directly surrounded by mesophyll, the distinguishing pitting (Fig. 4A, B). Water pores (Fig. 5 A, Fig. 6 A) were also found along such vessel elements on the adaxial surface of the leaf. It is assumed from these observations that such vessel elements may have an immediate connection with guttation of rice leaves.
