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Research Team
Research Team
This project would not have been possible without the support of the students of BIO400WC.
Emily Massar
Emily Massar
Biology Major, Pre-Health Studies Co-Major, Spanish Minor
Mackenzie Pottmeyer
Mackenzie Pottmeyer
Biology Major, Pre-Health Studies Co-Major
Faculty Advisor: Dr. Jonathan Bauer, PhD
Faculty Advisor: Dr. Jonathan Bauer, PhD
Biology Department
Abstract/Introduction
Abstract/Introduction
Microbial mutualisms are essential for plant health, nutrient cycling, and ecosystem stability. Arbuscular mycorrhizal fungi (AMF) enhance plant nutrient uptake, water absorption, and stress tolerance. Understanding these relationships is critical for grassland restoration and agricultural productivity. This study is intended to evaluate how different AMF isolates and different pathogenic fungi affect plant growth and biomass. It aims to assess variation in plant performance across microbial treatments. Currently, there is limited understanding of how different AMF isolates interact with pathogens within plant systems. It is unclear whether different AMF isolates provide equal protection to host plants. This study aims to support previous research regarding AMF’s role in plant ecosystems.
It is hypothesized that plants treated with AMF will grow taller, and that plants treated with pathogenic fungi will experience stunted growth or death. Differences among AMF isolates may result in varied growth and success.
Methods
Methods
Study Species: Andropogon gerardii
216 total seedlings grown under greenhouse conditions
Natural light supplemented after 2 weeks
Watered twice daily to maintain soil moisture
Pots filled with 50/50 clay loam topsoil and sand mixture
Soil sterilized via autoclave (1 hr)
10 mL AMF (arbuscular mycorrhizal fungi) added per treatment pot, six treatment groups (n=36)
Pathogens introduced as part of experimental treatment conditions
23 plants survived, 193 replaced with healthy seedlings (week 2)
Measured biomass of each plant (week 10); total of 36 plants remained at time of final harvest
Results/Findings and Discussion
Results/Findings and Discussion
Results
The average biomass varied across AMF treatments, with an overall mean biomass of 0.0172 g (SD = 0.0163, n = 34). Among treatments, LS4 exhibited the highest average biomass (0.028 g), followed by LM6 (0.0192 g) and KSC1 (0.0171), while LC1 (0.014 g), the control (0.0133 g), and ERC2 (0.012 g) showed lower values (Figure 1). An unpaired, 2-tailed t-test was performed (ɑ = 0.05), producing a p-value of 0.035. Despite these differences in mean biomass, variability within treatments was relatively high, as indicated in the overlapping standard deviation error bars (Figure 1). These results suggest a trend toward increased biomass in certain AMF treatments, specifically LS4, although variation within groups was substantial.
Average biomass between plants treated with different pathogens differed significantly. Control group plants treated with no pathogen exhibited a mean biomass of 0.021 g. Plants that received pathogen 1 had an average biomass of 0.027 g. Plants that were treated with pathogen 2 displayed a mean biomass of 0.016 g. Lastly, plants inoculated with pathogen 3 presented a mean biomass of 0.009 g (Figure 2). Biomass values ranged from 0.005 g to 0.06 g. An unpaired, 2-tailed t-test was performed (ɑ = 0.05), producing a p-value of 0.0049. Statistical analysis revealed the significant difference in biomass across groups (Table 2). Together, the results displayed significant differences across groups with respect to AMF and pathogenic treatment type (Tables 1, 2; Figures 1; 2).
Discussion
Our results indicate that arbuscular mycorrhizal fungi (AMF) can influence plant growth, but the effects vary depending on the specific isolate. Some treatments, particularly LS4, were associated with higher average biomass, suggesting that certain AMF strains provide greater benefits to host plants. However, other isolates showed little to no improvement compared to the control, highlighting that not all AMF relationships are equally beneficial.
Pathogen treatments had a more consistent impact on plant growth. While some pathogens appeared to have minimal effects, others significantly reduced biomass, indicating differences in pathogen severity. Interestingly, one pathogen treatment resulted in higher average biomass than the control, which may reflect variability in pathogen virulence or plant responses under the given conditions.
Due to high seedling mortality and a reduced sample size, we were unable to fully assess interactions between specific AMF isolates and pathogens. As a result, conclusions about whether AMF provides protection against pathogens remain limited. Future research with larger, more consistent sample sizes will be necessary to better understand these interactions and the role of AMF in plant defense.
Overall, this study supports the idea that microbial relationships play an important role in plant performance, but also emphasizes that these effects are complex and context-dependent.
Conclusions and Future Study
Conclusions and Future Study
Key Findings - AMF inoculation influenced plant biomass, with some isolates (e.g., LS4) showing greater growth benefits. Not all AMF treatments resulted in increased growth, highlighting variability among isolates. Pathogen treatments significantly impacted plant biomass, with some pathogens reducing growth more than others.
Overall Interpretation - AMF effects on plant growth are isolate-dependent and may vary in strength. Pathogens have a more direct and consistent negative impact on plant performance. Interactions between AMF and pathogens remain unclear based on current data.
Future Directions - Increase sample size to improve statistical power and reliability of results, prevent early seedling loss to maintain consistent experimental groups, further investigate interactions between specific AMF isolates and pathogens, and incorporate additional measurements to better understand mechanisms.
Limitations - High seedling mortality reduced sample size and experimental consistency. Replacement of plants may have introduced variability in growth stages. We were unable to draw conclusions about AMF–pathogen interaction effects due to limited data.
Acknowledgements
Acknowledgements
We would like to thank our advisor, Dr. Jonathan Bauer, for his guidance and valuable feedback throughout the course of this project. We are also grateful to our classmates in BIO400WC for their collaboration and assistance with data collection. Additional thanks to the laboratory and greenhouse staff for providing the resources and space necessary to conduct this research.
References
References
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NACE Career Readiness Competencies
NACE Career Readiness Competencies
Throughout this research project, we demonstrated several key NACE Career Readiness Competencies including, but not limited to, teamwork, critical thinking, and communication.
Teamwork was evident through our collaboration as a class to carry out this experiment. By working together to solve problems and stay organized, we ensured that each part of the project was completed effectively and on time.
Critical thinking played a key role in how we approached our research question and interpreted our results. Throughout our experiment we faced challenges regarding the health of our plants, which led us to results that differed from our initial hypothesis. With the use of critical thinking, we were able to analyze these unexpected results and still reach conclusions that were worthwhile.
Communication was demonstrated through both the creation of our research poster and verbal discussions. We presented our research poster in a clear, structured format, making our findings comprehensible to others. Additionally, we communicated within our class throughout the project to share ideas and advice.
Together, these NACE Career Readiness Competencies strengthened the quality of our research and helped us produce a well-organized and thoughtful final project.
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