Comparison of Gametophytic Callus and Tumor Tissues of Pteridium aquilinum

Abstract

A comparison of the fates of isolated fragments of two morphologically similar forms of disorganized growth of the gametophyte of Pteridium aquilinum establishes a basic difference between environmentally induced callus and spontaneous or radiation-induced tumors The callus, induced by dark culture on high sucrose concentrations, is readily revertible to normal gametophytic growth under normal culture conditions, the reversion following a characteristic apical developmental pattern By contrast, the tumor is self-perpetuating under normal culture conditions through repeated lateral divisions which give rise to a multiply branched filamentous structure Certain normal developmental attributes can be imposed upon the isolated tumor filaments, at least temporarily, in the presence of an auxin. These include apical divisions and differentiation of some of the lateral cells into rhizoids