... formationSupported by the Ministry of Education, Youth and Sports of the Czech Republic, Project No. MSM 6215648902, and by the Ministry of the Environment of the Czech Republic, Project No. SP/2d1/93/07, and ... however, there were diff erences of weeks in the timing of the formation of the tissues. It means that the factor which describes the variability of phloem tissue growth when comparing young and ... is not the number of cells but the timing of their for-mation. When the results obtained in the old stand were compared with the results of other authors, it was found out again that the diff...