THE FORMATION OF THE REGENERATION BLASTEMA IN PLANARIANS GIRARDIA TIGRINA
The aim of the work was to analyze the positional differences in the ability to regenerate body parts in planarian Girardia (Dugesia) tigrina. It will be shown the value of the size and position of individual fragments of planarians differences in their ability to regenerate, and the fundamental difference in the mechanisms of formation of head and tail blasts. The proposed scheme of regeneration includes two populations of pluripotent stem cells – neoblasts differing as the role and distribution along the planarian body. Based on the results of the scheme of planarian regeneration, including two populations neoblasts differing as the role and distribution along the planarian body. In particular, the population neoblasts involved in the formation of any blastema, migrates to the nearest blastema, and the population participating only in the creation of blastema head migrates along the planarian body part on a gradient of biomass damaged axons arising after the amputation of the head. The maximum size of the head detected in blastema fragment obtained after cutting head fragment at eye level, and the maximum of all pluripotent stem cells migrating into two blastema, found in fragment obtained planarians transection at the level above the mouth, followed by cutting off the head piece at eye level.