Here, tomato plants were grown from seed in potting mix for two weeks , watered with ultrapure water. All the seedlings were unpotted and their roots were washed, then half were inoculated with TSth and the rest weren’t. All the seedlings were planted in coarse tailings for two weeks, watered as before. Pictures of four week-old plants show that those treated with Tsth (left) were larger.
Some fungi form beneficial partnerships with plants called symbioses, generally defined as ‘different organisms living together’.
Fungi called arbuscular mycorrhizae (AM) help plant roots absorb nutrients. Roots produce chemicals that attract growth from AM spores (fungal seeds) in the surrounding soil. Once a symbiosis is formed, AM fungi provide minerals and water for plant growth and drought tolerance in return for sugars from photosynthesis.
Other fungi do more. At the University of Saskatchewan, Susan Kaminskyj and colleagues recently showed that certain fungal strains help plants grow in harsh environments. One of these, called Tsth, helps plants grow on dry, low-nutrient ‘coarse tailings’ (CT) that also have an oily residue. CT are a high-volume by-product from refining Athabasca oil sand that must be restored to self-sustaining boreal forest.
In her lab, Kaminskyj’s group compared the growth of tomatoes grown in CT with or without TSth. As shown in the images, plants colonized with Tsth grew more than twice as large on CT as ones without it. Her team is already using endophyte fungi with various cover crops and grasses, and looking for places to confirm that this growth enhancement also works outdoors.
Finally, Kaminskyj’s group is also studying fungal strains that help plants to grow instead on salty or acid soil.
[Ed. note: the above article was co-authored by SFC contributor, Janet Wallace, and Susan Kaminskyj, of the University of Saskatchewan (susan.kaminskyj@usask.ca)]
- Janet Wallace and Susan Kaminskyj