Biomics

The effect of copper ions (100 and 200 μM CuSO4) in a long-term experiment on the activity of class III peroxidases and PRX gene expression level in the root and stem of juvenile zinnia plants was studied. It was found that an increase in the content of copper ions in the root system was accompanied by the rise of hydrogen peroxide, which led to the growth of the activity of neutral guaiacol peroxidase (GPO) and acid benzidine peroxidase (BPO). The relative number of PRX gene transcripts also increased in the root that caused additional lignification, especially, Klason lignin. In the stem, the copper content in the experimental plants was comparable to the control level. An increase in the activity of peroxidases contributed to a decrease in the amount of hydrogen peroxide in this organ and was accompanied by a compensatory rise in the lignin content. The increase of the expression level of PRX gene suggests its role in the formation of plant resistance to the prolonged impact of copper ions due to enhanced lignification of cell walls.

cell walls, lignification, metaxylem, class III peroxidases, phenols, heavy metals

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