The effect of soil fertility on antioxidant enzymes activity in a subarctic woody species

The influence of major nutrients’ reserves (available to plants) – nitrogen (N), phosphorus (P), potassium (K) – in the top 25-cm layer of soil on the Karelian birch (Betula pendula Roth var. carelica (Mercl.) Hämet-Ahti) with non-figured and figured wood via the antioxidant enzymes’ activity was investigated. The analysis of sites in area where Karelian birch trees with varying degree of figured wood intensity were growing was carried out. The cambial zone of the sample trees during active cambial growth period was studied for the activity of AOS enzyme complex (superoxide dismutase (SOD); catalase (CAT); peroxidase (POD); polyphenol oxidase (PPO)). Cellulose content and lignin content were studied. It was noticed that the availability of major nutrients in the investigated sites had influence on the degree of figured wood intensity in Karelian birch plants. Thus, non-figured and figured Karelian birch plants that grew on sites with various levels of major nutrients’ reserves differed in the AOS enzymes’ activity, which was a consequence of different xylogenesis scenarios in the studied birch forms. It was supposed, that the certain site conditions (N, P, K levels) formation could affect the degree of figured wood intensity, cellulose and lignin content. The N level and P/N ratio had the most effects under the adequate K level. So AOS enzymes’ complex activity could indicate differences in Karelian birch wood quality in sites that differ in soil fertility (N, P, K levels).