SENSITIVITY OF BETA GLUCOSIDASE TO SOIL CONTAMINATION WITH ZINC, COPPER, NICKEL, CADMIUM AND LEAD

In the experiment, loamy sand, sandy loam and sandy clay loam with a pH of 7.0 and 5.5 were contaminated with Zn2+, cu(2+), Ni2+, Cd2+ and Pb2+ in the laboratory. The analyzed substrates differed in their chemical properties, and therefore they were contaminated with six different doses of each metal. Substrate samples were incubated for 30, 60 and 120 days, and the activity of beta-glucosidase was determined at the end of each incubation period. The results were used to calculate the enzyme's resistance to soil contamination with heavy metals. Enzyme activity in soil with natural levels of trace elements ranged from 0.539 mM PNP kg(-1) h(-1) DM in sandy clay loam with a pH of 7.0 to 0.247 mM p-nitrophenol (PNP) kg(-1) h(-1) DM in the same substrate with a pH of 5.5. The highest levels of beta-glucosidase activity were noted in sandy clay loam, and the lowest in loamy sand. In acidic soils, enzyme activity increased after the first incubation period (30 days), whereas in neutral substrates, higher levels of P-glucosidase activity were observed after two successive incubation periods (60 and 120 days). beta-glucosidase was most resistant to contamination with Cu2+ (RS=0.997) and least resistant to contamination with Zn2+ (RS=0.097).