EFFECTS OF COLCEMID ON HYDRA VIRIDIS WITH MULTIPLE-PEDUNCLE GRAFTS

The effect of Colcemid on multiple-graft Hydra viridis containing three peduncles (3p) grafted in tandem is reported. At grafting, the apical member of a 3p animal is a foot-less host, the middle member, an isolated peduncle, and the proximal member, a foot-bearing peduncle. In different experimental situations all three members are treated with Colcemid, the host member alone is treated, or the host member is not treated but the others are. Control animals have only non-treated members. Head and foot regeneration on graft pieces and the formation of waists and separations at the borders between these pieces are monitored and the significance of differences between frequencies tested by Chi square. Head formation on the middle and proximal peduncles is promoted by Colcemid when all pieces are treated, but animals with treated host pieces have significantly higher frequencies of heads on their non-treated proximal pieces than other experimental and control animals. Animals with Colcemid-treated proximal peduncles do not have significantly more heads on the most proximal peduncle compared to controls. Colcemid does not alter the frequency of foot formation significantly on the host peduncles of animals in the different categories, but foot formation is increased on the middle pieces of animals with three treated pieces and on animals with middle and proximal treated pieces. The rate of waist formation and graft separation is retarded when all three or just the host piece is treated, but not when only the middle and proximal pieces are treated. The direct action of Colcemid on nerves and on dividing cells may be responsible for these effects.