Role of ericoid mycorrhizas in establishment of ericaceous plants in oil sands reclamation areas

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Land reclamation efforts following oil sands mining are challenging due to the harsh climatic conditions and the severity of land disturbance. In many reclamation areas, soil contains elevated salinity and high pH. Plants suffer from drought conditions due to low soil moisture content, high atmospheric vapor pressure deficit and post-planting stress. The problem is aggravated by the lack of knowledge concerning some of the fundamental processes that affect plant growth and survival in reclamation sites, especially for the forest understory plants. Plants of the Ericaceae family play important ecological roles in the boreal forests and are of special cultural importance to the First Nations people. Their growth in reclamation sites is severely impacted by the soil factors. Plants of this family require a specific type of ericoid mycorrhizal associations to enhance their resistance to unfavorable soil factors in reclamation sites. Therefore, in the present project, we will examine the role of ericoid mycorrhizal associations in conferring high pH, salinity, and drought resistance to ericaceous plants and the processes involved in these plant responses. The main long-term objective of the proposed study is to contribute new knowledge concerning the physiological processes in ericaceous plants colonized by the ericoid mycorrhizal fungi. Specific objectives are to i) identify the ericoid mycorrhizas in the rhizosphere of upland and lowland blueberry, Labrador tea and lingonberry plants in natural forest sites and in oil sands reclamation areas, ii) examine whether ericoid mycorrhizal associations enhance high pH, drought and salinity tolerance in these three ericaceous plant species, iii) determine the effects of ericoid mycorrhizal associations and pH on water relations of upland and lowland blueberries and the role of plant and fungal aquaporins in these responses, and iv) examine the growth responses of mycorrhizal plants following planting in oil sands reclamation areas. The project consists of several studies which will be carried out in growth rooms under controlled conditions and in the field. The results of the study will be used to improve revegetation of oil sands areas with ericaceous plants.