Study of antioxidant enzymes’ activity in reaction wood of poplar tree (Populus alba L.)

Studying biochemical variation in reaction wood is needed to understand the nature of reaction wood formation and the physiology of trees. The activity of antioxidant enzymes (superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX) and guaiacol peroxidase (GPX)) was studied in normal wood (NW) and reaction wood (RW) (opposite wood (OW) and tension wood (TW)) in the bole of poplar trees (Populus alba L.). Four-year-old trees were induced to produce reaction wood by forced bending. The activity of antioxidant enzymes was studied with repeated sampling during a growing season. The results showed that total protein content and antioxidant enzymes are sensitive to mechanically induced stress. TW and OW showed higher activity of enzymes than NW as well as higher amounts of total protein. OW showed a higher concentration of CAT and SOD than TW. APX was more active than GPX in both TW and OW. In addition to mechanical stress, the effect of other climate factors was observed in the reactive oxygen species accumulation.