EXPERIMENTAL INDUCTION OF DILATATION MERISTEMS IN MELIA-AZEDARACH L

Dilatation meristems were induced experimentally in the bark of Melia azedarach L. by mechanical bark blocking, wounding, and by application of 1-0% of either naphthaleneacetic acid (NAA) or of ethrel. The treatments induced the formation of dilatation meristems in the rays, in the axial phloem parenchyma, and in the primary cortex.Dilatation was the result of both cell divisions and cell enlargement. The dilatation meristems were sometimes several cells wide, and were formed in all possible orientations; some were even branched. In many cases, whirls were formed as the result of dilatation activity in many directions over a small bark area. The possible hormonal regulation of dilatation activity is discussed. © 1992 Annals of Botany Company.