Rhizosphere Effects on Soil Enzyme Activities in Red Pine (<i>Pinus </i><i>resinosa</i>) Stands

The rhizosphere, located under the plant roots, is a vital part of plant life. It is a complex community of microbes, minerals, and enzymatic activity. These components allow for nutrient cycling within the soil and plant roots ecosystem, which is necessary for plant survival. Several studies have focused on the biogeochemical cycling of elements in this microenvironment. This study aims to have a better understanding of the rhizosphere effect on microbial activity in soils. Soil samples were collected from three different locations in Sudbury, Ontario, Canada. At each site, soil samples were collected from the rhizospheres of red pine (Pinus resinosa) trees. Surrounding non-rhizosphere soils collected from three separate areas were used as controls. Activities of nine different enzymes were analyzed due to their roles in ecological processes. They included β-glucosidase (BG), cellobiohydrolase (CBH), β-N-acetylglucosaminidase (NAGase), aryl sulfatase (AS), acid phosphatase (AP), alkaline phosphatase (ALP), glycine aminopeptidase (GAP), leucine aminopeptidase (LAP), and peroxidase (PER). Results of this study showed that activities of AP, ALP and AS involved in the cycling of elements such as phosphorus and sulphur were significantly increased in the rhizosphere compared to control sites. Other enzymes, such as BG, CBH, NAGase, GAP, LAP, and PER, appeared to be more conditioned by external environmental factors. More studies are required to determine the role of targeted enzymes in the rhizosphere.