Peroxidase activity in organs and tissues of silver birch trees

Silver birch trees with different degrees of manifestation of wood grain patterns were studied to reveal acid and alkaline peroxidase activity in the phloem and xylem parts of the cambial zone during the trees' growing season. Peroxidase activity in the phloem tissues of both types of silver birch was elevated in xylem tissues. Correlations between peroxidase activity and intensity of the cambial growth were negative. In June, when growth processes commenced in the trunk, peroxidase activity dropped significantly when compared to data obtained in May. At this time, cambium was not yet active. Later in July, a prolonged high temperature period resulted in substantial inhibition of cambial activity. Peroxidase activity in both acid and alkaline forms of the enzymes rose during this period both in xylem and in phloem tissues. High enzyme activity was found only in tissues of curly-grained trunks. Peroxidase activity in straight-grained plants did not change. Possible pathways of peroxidase involvement in the processes of abnormal morphogeny of woody plants are discussed.