Effects of Commercial and Native Mycorrhizae on Two Warm Season Grasses]

Abstract

Mycorrhizal fungi help plants acquire nutrients from the soil in exchange for organic carbon. Our goal is to determine the effects of commercial mycorrhizae vs. native mycorrhizae on plant growth depending on the sympatric/allopatric relationship between the soil, fungus, and plant. We hypothesized that plants exposed to mycorrhizal fungi, whether it is commercial or native, will have the greater biomass than those without fungi. The plant species used were Bothriochloa ischaemum and Andropogon gerardii. The seeds of these were divided and put equally into sterile soil with or without inoculum. Inoculated groups were given ¼ teaspoon of Plant Success Endo- and Ecto-Mycorrhizae. Height was recorded weekly for each plant, and were dried and weighed to determine biomass. Our findings did not support out hypothesis. There was not a significant difference in biomass between the commercially added and the wild mycorrhizae. Sterile, non-inoculated soil resulted in greater biomass and height in both species.  This suggests that mycorrhizal association did not benefit our specific grass species. It is also possible that if the experiment had run longer, we would have had different results, as mycorrhizae are usually required for grasses to complete their life cycle. Additional research could be done to determine if the amount of inoculum added affects plant fitness, as it is possible too much of the fungus could parasitize plants.