Pattern and Control of Sclereid Formation in the Leaf of Camellia japonica

Abstract

EXCELLENT material for the study of factors controlling cell differentiation may be found in the sclerenchymatous idioblasts present in the leaves of certain higher plants. Outstanding examples of this cell type are the lignified sclereids that occur in leaves of Camellia japonica L. During the course of an investigation on sclereid formation in this species I observed the striking distributional pattern of these cells in cleared leaf preparations. In C. japonica the sclereids occur predominantly near the lateral margins of the leaf from apex to base and, to a lesser extent, along the length of the mid-vein and scattered throughout the lamina. The distribution of sclereids along a line parallel and close to the leaf margins constitutes a unique pattern, one not hitherto described for any other species.