Shoot Apex Organization in Tamaricaceae

Eighty six freshwater algal spThe shoot apex organization has been studied in three species of Tamarix and in one species of Myricaria. The shoot apices in all the species are dome shaped. On the basis of the plane of division, differences in cell size and shape, the shoot apex shows four zones which do not show much variation cytohistologically in different phases of plastochrons. These zones are-one layer of tunica, central zone of corpus mother cells, radiating zone on either side of the central zone (Flank zone) and zone at the subjacent level (Rib zone). In all the species the pattern of leaf development is same. The initiation of leaf is marked by the periclinal divisions in the first layer of corpus. The apical growth takes place by the differentiation of sub apical initials, which are differentiated at an early stage in the leaf buttress. The lamina is initiated by the marginal and submarginal initials differentiated along the two margins. The marginal initials divide only anticlinally and form the protoderm. The submarginal initials, have two cutting faces, which cut off cells adaxially and abaxially.