ROOTS 2011 WORKSHOP
Finnish Forest Research Institute
The quality of polluted soil can much be improved and the environmental risks reduced by use of phytoremediation. Harmful hydrocarbon compounds can be degraded through the activity of plant and its associated microbes. We previously showed that PAHs increase aromatic ring-cleavage gene diversity in rhizosphere of birch (Sipilä et al. 2008, Yrjälä et al. 2010a) and the rhizosphere of aspen harbors Burkholderia bacteria able to degrade aromatics (Yrjälä et al. 2010b). The results are promising for successful remediation of polluted soils with woody plants. The aim of our studies is to elucidate the response of the plant and the associated bacteria to oil pollution and high salt. In a long term greenhouse experiment the effects of petroleum hydrocarbons and high salt on aspen seedling clones and on bacterial populations were studied. The root morphological plasticity of four selected aspen clones was studied. In the long term experiment with soil from an accidental oil spill, the abundance of catabolic ring-cleavage genes was elevated in the rhizopsphere. Stress effects on root morphology were detected, but one of the clones differed in that it hardly responded to the treatments. The height growth of trees correlated positively with specific root length and area. It can be concluded that certain bacteria populations are clearly favored by oil pollution, especially in the rhizosphere. The aspen seedlings may generally try to increase fine root length and surface area in response to oil but with clear exceptions.
Yrjälä, K., Ostonen, I., Mukherjee, S., Sipilä, T., Vaario, L.-M. and Pulkkinen, P. 2011. Fine roots of aspen clones in high salt and petroleum hydrocarbon pollution. In: Roitto, M., Lehto, T., Sutinen, S., Finér, L. and Repo, T. (eds.). ROOTS 2011 WORKSHOP, Abstracts, Joensuu, Finland, 13-14 December 2011. Metlan työraportteja / Working Papers of the Finnish Forest Research Institute 214: 37.