Enzymes in the rhizosphere of plants growing in the vicinity of the Polish Arctowski Antarctic Station

Abstract

In maritime Antarctica soil enzymes have been little researched, mainly in the rhizosphere of the only two vascular plants that grow there: Colobanthus quitensis and Deschampsia antarctica. This study evaluated the activities of hydrolytic enzymes β-glucosidase, phosphatase and urease in the rhizospheric soils of C. quitensis and D. antarctica from three different sites in the Polish Arctowski Station in Antarctica. The sensitivity to temperature changes of the enzymes was also evaluated using two incubation temperatures (37 and 12 °C). The highest activities related to the C and P cycles, β-glucosidase and acid phosphatase, respectively, were detected in the rhizospheric soils at the site with the greatest variety of plant cover. Urease activity, related to the N cycle, was high in two of the three sites, and the lowest activity was detected at the site where only D. antarctica was found. The activity of the enzymes decreased when the temperature of incubation was reduced, but the magnitude of the decrease depended on the enzyme. β-glucosidase was the most sensitive to temperature change, whereas urease was least affected. Therefore, temperature changes in rhizospheric soils could lead to changes in substrate degradation rates and consequently in the availability of nutrients (C, N and P) for C. quitensis and D. antartica in maritime Antarctica.