Models of sclerification of Betula pendula (Betulaceae) bark tissues in nature and in an experiment.

摘要

The pattern of sclereid differentiation in the bark of different forms of Betula pendula was studied during normal ontogenetic development and during regeneration after mechanical injury. The hypothesis was tested that sclereid differentiation is induced by defined auxin and sucrose concentrations. On this basis, different models of bark tissue sclerification are discussed. It is concluded that the appearance of the sclereids in the pericambial zone of phloem as well as the formation of wide abnormal rays is apparently connected with the accumulation of excess amount of assimilates in certain parts of conducting phloem.