ACTIVITIES OF ENZYMES PARTICIPATION IN REDOX POTENTIALIN THE TWO DEPTHS OF TAGAN PEATLAND L.W. Szajdak, L.I. Inisheva, T. Meysner, W. Gaca, K. Styla

szajlech@man.poznan.pl

**Testing Agroecology Laboratory, Tomsk State Pedagogical University, Tomsk, Russia, inisheva@mail.ru

The redox potential is a critical environmental factor because it governs the chemical and biochemical form of many compounds and their availability for plants and soil microorganisms.

Soils samples were taken from four places marked as No 1, 2, 3 and 4 each from two depth 0-25 and 50-75 cm of the peatland Tagan. Peatlands Tagan is located near Tomsk, West Siberia, Russia. Place No 1 in both layers represents grasses peat with the degree of the decomposition ranged from 25 to 35 % (pH 6.31-7.95). Point 2 is characterized by wooden and wooden grasses peat with 35 % degree of the decomposition (pH 5.16-9.31). There is buckbean peat in the points 3 and 4 (pH 6.4-6.49). However, 1,5 m depth of sapropel is located in point 4.

Dissolved organic matter and total organic matter, reductase, xanthine oxidase, phenol oxidase and peroxidase activity were determined in the soil samples. It is known that organic matter is capable of inducing reduction and oxidation reactions, hence affecting the redox system in the environment. Our research showed that the dissolved organic carbon concentration ranged from 5,67 to 10,92 g kg-1 and total organic matter from 314,0 to 436,8 g kg-1 in all of sampling.

Nitrate reductase is enzyme involved in the process of denirification. Nitrogen present in the structure of this enzyme acts as a terminal acceptor of electrons instead of molecular O2 by bacteria and is irreversible once NO is formed. The investigation has shown that nitrate reductase activity in the soils reached from 0.11 to 0.68 pgN 24h-1 g-1 in all of sampling.