The Affects of Brassica Nigra on Arbuscular Mycorrhizal Fungi Abundance

Mycorrhizal fungi provide important ecosystem services to plants, such as helping  increase plant nutrient uptake and mineral absorption, resulting in improved plant vitality and increased growth and quantity of plant biomass. Our main research focus examines how invasive plants, such as the non-mycorrhizal plant, Brassica nigra, affect the abundance of obligate biotrophic arbuscular mycorrhizal fungi associated with native plants from an invaded grassland habitat. We predict that presence of Brassica nigra inhibits mycorrhizal fungi and thus reduces fungal abundance in soils. Soil samples were taken from an intact native grassland habitat (<50% native), manually managed Brassica nigra plots (30-50% native), highly invaded plots with high Brassica nigra cover (<10-15% native), as well as introduced Brassica nigra experimental plots. Plant bioassays will be performed with the native plant, Stipa pulchra, grown in each soil type. After harvesting the plant bioassay, soil hyphal extractions will be performed on all samples in order to investigate the difference in fungal abundance among these soil types. Extracted hyphae will be stained and examined under a microscope to quantify mycorrhizal abundance and evaluate the effect of B.nigra on fungal abundance in invaded and restored Southern California grasslands.