THE GROWTH AND DIVISION OF CELLS IN RELATION TO MORPHOGENESIS IN FERN GAMETOPHYTES: I. PHOTOMORPHOGENETIC STUDIES IN PTERIDIUM AQUILINUM

Abstract

The development of the fern gametophyte is affected by a number of rather diverse treatments. In particular the spectral quality of light has a strong influence on the change in form of the gametophyte. It was reconfirmed that in the developing fern gametophyte red light promotes elongation whereas in blue light the magnitude of elongation is greatly reduced. A correlation between rate of cell division and two-dimensional form was found. A high rate of cell division promotes the formation of a gametophyte that is increasing both in length and in width while a low rate of division promotes the formation of a gametophyte that is increasing primarily in length. On the basis of this observation the change in the form of the gametophyte is interpreted to be directly related to the rate of cell division, which in turn influences the plane of division. This interpretation is also applied to the transition from unidimensional to two-dimensional growth in the developing gametophyte.