Developmental properties of induced buds from a nonbudding mutant of Hydra viridis

Abstract The apical portions of the nonbudding mutant of Hydra viridis were induced to bud by grafting to them basal portions of wild type hydra of the same species. The induced buds had unusual developmental and morphogenetic properties that frequently showed characteristics of both wild type and mutant animals. The rate and extent of bud induction varied depending upon the body region of the wild type tissue grafted to mutant tissue. The gastric region induced the most buds at the highest rate. Induced buds containing cells from both the wild type and the nonbudding mutant were referred to as “heterocytes”. Wild type heterocytes were more like the mutant. Mutant heterocytes had regeneration properties characteristic of both the wild type and mutant animals depending upon how long they had been fed. The initial budding rates of the wild type heterocytes varied, but eventually all wild type heterocytes transformed into animals of mutant phenotype. These observations suggest that complex interactions are taking place in the heterocytes composed of cells derived from both the wild type and the nonbudding mutant.