Rhizoremediation in cold climates

Abstract

Rhizoremediation has become increasingly interesting as it offers several solutions to environmental problems by making use of plants. The International Phytotechnology Society (http://phytosociety.org/) defines phytotechnology as the strategic use of plants to solve environmental problems by remediating the qualities and quantities of our soil, water, and air resources and by restoring ecosystem services in managed landscapes. Plants always interact with belowground microbes, bacteria, fungi, and archaea, and even aboveground epi/endophytic microbes. The recent adoption of omics techniques has led to much widened understanding of soil microbial communities, and conditions that promote predictable activity in contaminated soils with effects on plants. These methods have in microbial ecology brought out new concepts like plant microbiome describing the wide array of microorganisms living and interacting in different ways with the plant. The identification of increasing numbers of microbes associated with plants helps to notify new functional groups of microbes that are and become important for applications of phytotechnology. In the boreal cold climate freezing and thawing of soil occurs, which shapes the active microbial communities in a peculiar way. Also in the cold season soil, microbes perform tasks important for ecosystem functioning. The plants create a suitable environment for microbes especially in the rhizosphere where root exudates are excellent food for microbes in the vicinity of roots. Woody plants have received increased attention, especially poplars (Populus spp.), when it was recognized that they can reduce the level of trichloroethylenes in soil with the help of endophytes. Poplars have successfully been used for rhizoremediation of petroleum and other hydrocarbon compounds.