Fertilizer vs. Fungi, Part II: How Nitrogen Fertilizers Affect Beneficial Mycorrhizal Fungi

Overview

Objectives/Goals The objective of this study was to determine whether exposure to nitrogen fertilizer will decrease the number of beneficial mycorrhizal fungi that grow into the root systems of California grassland plants. The fungi assist their host plants in water and nutrient uptake and provide protection from pathogens. Methods/Materials Collected experimental and control soil samples, extracted and rinsed plant roots, stained plant roots using 2.5% potassium hydroxide, 1% hydrochloric acid, an acidic glycerol/trypan blue mixture, and acidic glycerol. Made permanent slides and counted the fungi using a compound light microscope. Extracted nitrate from soil using 2.5% potassium chloride, then performed nitrate tests using cadmium powder and a nitrate testing kit. Results I counted beneficial mycorrhizal fungi for plant roots with and without exposure to nitrogen fertilizer. The plant roots not exposed to fertilizer showed more mycorrhizal fungi than those exposed to fertilizer. Nitrate levels in the soil with and without added nitrogen fertilizer were tested. The soil with fertilizer added had a higher level of nitrate than the soil without fertilizer added. Conclusions/Discussion The plant roots exposed to nitrogen fertilizer had fewer beneficial mycorrhizal fungi than those not exposed to nitrogen fertilizer. I concluded that nitrogen fertilizers can lower the number of beneficial mycorrhizal fungi in plant root systems. This indicates a potential harmful side effect of the use of chemical fertilizers.

Competition history

• CSEF 2018 Microbiology (General) · Entry S1609

Resources

• CSEF project summary ↗

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