The analysis of tree ring anatomical characteristics (cell production, cell radial size (D), cell wall thickness (CWT)) has been conducted for P. sylvestris rootstock and two scions: P. sibirica and P. cembra. The P. sibirica scions were from two different provenances (Еmelyanovo (EM) and Surgut (SU)).We found an increase of cell production of P. sibirica scions relatively to the control tree stand by a factor of 1.2 (EM) and 1.3 (SU) times. The radial cell dimensions increased by 15% (ЕМ) and by 13% (SU), while the CWT increased on 15.3% (ЕМ). The cell parameters of Scots pine rootstock have been altered in both directions: in the direction of decrease (cell production, D and CWT of ЕМ and КА; cell production and CWT of SU), also in the direction of increase (D of SU). The degree of alteration depends on the species of scion. The seasonal dynamics of grafted tree parameters D and CWT maintains its species-related characteristics as in non-grafted tree stand, which indicates that the genetic program of cell differentiation is stable. The adaptive abilities of scions are not reflected in any way in the anatomical structure of rootstock tree rings for the years in which the climatic conditions were close to the climate of scion’s place of origin. On the contrary, the display by the scion of the climate reactions characteristic of the rootstock points to the significant role of the latter in the control of xylem formation. The alteration of cell parameters in both graft components and their coordinated growth suggests that they are both involved in the control of cell differentiation as well as their ability to “adjust” to each other.