Publication Date

Fall 2014

Document Type


Degree Name

Master of Science


Environmental Biology

First Advisor

Mary E. Carrington, Ph.D.

Second Advisor

Timothy Gsell, Ph.D.

Third Advisor

John Yunger, Ph. D.


Arbuscular mycorrhizal fungi (AMF) form a relationship with a multitude of host plants that is estimated to include 70-90% of terrestrial plant species over a wide range of environments. AMF and other microbiota, as well as abiotic factors are an important component of plant-soil feedback systems. The effects of plant species and soil type on root characteristics, plant-soil feedback and influence on microbiota and arbuscular mycorrhizal colonization were assessed through a manipulative laboratory study. Aster laevis, Parthenium integrifolium, Aster novae-angliae and Andropogon gerardii were grown in sterilized control soil and soil collected from beneath monocultures of A. laevis, P. integrifolium, and A. gerardii. Soil type (heterospecific and conspecific sources) was expected to have the largest influence on root characteristics and AMF colonization. Microbial community carbon metabolism became more homogenous after the study was completed. It was found that both plant and soil had similar influence. Negative feedback was expected for plants grown in A. gerardii soil, but the opposite was observed. The relationships between AMF colonization and fine root branching, and between AMF and specific root length were hypothesized to be negative. Specific root length was found to be negatively correlated to proportion mycorrhizal colonization, but fine root size and branching characteristics were not correlated with AMF colonization. Total biomass was positively correlated with proportion mycorrhizal colonization. It was found that mycorrhizal dependence of the four prairie species studied was high and plant death only occurred in 26 sterilized control soils. No net feedback was observed for A. laevis, P. Integrifolium, and A. gerardii.