This summer, two of Plant Chicago’s interns are working on a project that can potentially benefit all farmers and gardeners in Chicago, especially those in areas with an industrial past. The topic of study is a special kind of fungus that lives in our soil, and creates special relationships with the plants growing around it. Keep reading to find out how this works, and what they dig up!
Introduction to: (Arbuscular) Mycorrhizal Fungi in South Side soils
AK Miller & Tyler Bogartz-Brown
Hello from Plant Chicago, Back of the Yards, Chicago, where we are searching for arbuscular mycorrhizal fungi in our urban soils! These special fungi, relatives of the ones who fruit into above-ground mushrooms, are underground beings who have the special job of partnering with the roots of plants for the benefit of the whole ecosystem.
Myco (fungi) + rrhizal (pertaining to roots)
Mycorrhizal = Root-fungi who gather water, nutrients, minerals, and information for plants. In exchange, the plant feeds its specialty—sugar from the sun—to the fungi. Not only do mycorrhizal fungi enter symbiotic relationships with plants, they facilitate and evolve relationships between the plants themselves. For example, mycorrhizal fungi help tall trees in the forest send sugars to shaded young saplings, nourishing the next generation. They also send information about invading diseases, helping trees and plants collaboratively adapt.
Arbuscular = this particular fungi inhabits the cells inside plants’ roots, forming arbuscules, or tiny tree-like structures for nutrient transport.
Arbuscular Mycorrhizal Fungi (AMF) are known to associate with more than 90% of plants. Nearly every plant, from oaks, to orchids, to corn, to herbs can partner with AMF, becoming more resilient and interconnected through these mutually beneficial relationships, literally sharing bodies to co-evolve.
We want to see if we can find, and hopefully identify, AMF living in our soils. These fungi are typically suppressed by contamination, compaction and the use of fertilizers. If they do survive here, the particular strains could be cultivated for the remediation of urban farm soils and for the creation of mycorrhizal inoculants that could reduce the use of fertilizers. We theorize that the older, less disturbed soils (such as the “weedy edge” of The Plant‘s yard and the forest preserve locations) will have more mycorrhizal fungi present than the newer, tilled farm site soils.
We’ve collected soils from five different sites at The Plant and five off-site locations, including other urban farms and forested areas. Our goal was to get samples of different “ages” to see if the AMF varies. We planted basil seeds in each of these samples. We also mixed each of The Plant soils with a bagged potting mix, and planted basil seedlings in each of these mixes. So far, the soils collected from forested areas (2nd and 3rd from left, Wooded Isle and Wolf Road Woods), and the fertilizer-containing potting mix (far right), have the best-performing basil seedlings!
We will be running the soil samples through a sieve set and spin them in a borrowed centrifuge in order to separate soil particles from potential fungal spores. Then, we’ll check them out under a microscope—arbuscular mycorrhizal spores should be round and big enough to spot. If we find some AMF spores, we can then try to ID them.
Later in the summer, we’ll also stain the roots of the mature basil plants to see if any root relationships have formed. We’ll keep you posted! –AK & Tyler