Theoretically, introduction includes acclimatization process, which is an expression of adaptive changes on the genetic and population level. It is known many current theories about acclimation, but unilateral and controversial. From our point of view, there are three adaptive types in the process of acclimatization: i) populational acclimatization (adaptation) of plant, whose magnitude of environmental resistance falls within the new growth conditions, ii) acclimatization through segregation of the characters at the population level. The heterogeneous material, within a short time, segregates and multiply resulting in new pre-adaptive genotypes, forming new introductive populations, becoming highly heterogeneous in the next generations iii) adaptive acclimatization occurs in the population-specifi c processing, resulting in the emergence of new adaptive forms of different rank at the species level, being naturalized and often naturalized.