Differentiation in Fern Gametophytes Treated with Purine and Pyrimidine Analogs.

Analogs of the purines, adenine and guanine, and of the pyrimidines, cytosine and uracil, completely inhibited two-dimensional differentiation in the gametophytes of the fern, Asplenium nidus L. Analogs of thymine caused a nonspecific growth inhibition without suppressing two-dimensional growth. The effects of the analogs were reversed by the respective bases or their derivatives.