Presentation Type
Presentation
Faculty Mentor’s Full Name
Cara Nelson
Faculty Mentor’s Department
Ecosystem Science and Restoration
Abstract / Artist's Statement
Purpose
Conyza canadensis is a ruderal annual that thrives under drought despite it lacking obvious xeromorphic traits, such as succulent leaves or deep roots. This plant is also highly colonized by arbuscular mycorrhizal fungi (AMF) making it an ideal candidate to study how mycorrhiza affects plant drought tolerance. The overarching objectives of this research were to determine whether 1) mycorrhizal Conyza plants are more drought tolerant than nonmycorrhizal Conyza plants under drought stress, and, if so 2) to gain insight concerning potential underlying mechanisms.
Methods
We used a 2x3 factorial design with two inoculation treatments (+AMF and -AMF) and three watering treatments (control, moderate, and severe drought). Each treatment was replicated eight times for a total of 48 plants. Conyza seedlings were grown for two months and drought was implemented using the wick method, which generated a constant difference in volumetric soil water content of 18%, 8% and 5% among drought treatments. We measured biomass, water content, leaf water potential, photosynthetic rate, stomatal conductance, and shoot nitrogen and phosphorus concentrations.
Significance
All inoculated treatments were mycorrhizal and all control treatments were non-mycorrhizal. Shoot and root biomass were lower in pots with increasing drought stress and, overall, AMF suppressed shoot but not root biomass. Total biomass responses to AMF inoculations changed from parasitic to neutral with increasing stress, suggesting a potential shift in cost-benefit ratios and mycorrhizal function. Although mycorrhizal plants had higher photosynthetic rates (P=0.05) than non-mycorrhizal ones, this upregulation was insufficient to prevent reductions of shoot biomass when conditions were benign. Mycorrhizal plants also had higher stomatal conductance (P=0.01) and shoot water content (P=0.02), which is indicative of lower drought stress in general. Leaf water potential became increasingly negative with drought stress, especially in the most stressed non-mycorrhizal plants (PAMFxDrought
Category
Life Sciences
Consequences of arbuscular mycorrhizal fungi on plant drought responses and possible mechanisms
Purpose
Conyza canadensis is a ruderal annual that thrives under drought despite it lacking obvious xeromorphic traits, such as succulent leaves or deep roots. This plant is also highly colonized by arbuscular mycorrhizal fungi (AMF) making it an ideal candidate to study how mycorrhiza affects plant drought tolerance. The overarching objectives of this research were to determine whether 1) mycorrhizal Conyza plants are more drought tolerant than nonmycorrhizal Conyza plants under drought stress, and, if so 2) to gain insight concerning potential underlying mechanisms.
Methods
We used a 2x3 factorial design with two inoculation treatments (+AMF and -AMF) and three watering treatments (control, moderate, and severe drought). Each treatment was replicated eight times for a total of 48 plants. Conyza seedlings were grown for two months and drought was implemented using the wick method, which generated a constant difference in volumetric soil water content of 18%, 8% and 5% among drought treatments. We measured biomass, water content, leaf water potential, photosynthetic rate, stomatal conductance, and shoot nitrogen and phosphorus concentrations.
Significance
All inoculated treatments were mycorrhizal and all control treatments were non-mycorrhizal. Shoot and root biomass were lower in pots with increasing drought stress and, overall, AMF suppressed shoot but not root biomass. Total biomass responses to AMF inoculations changed from parasitic to neutral with increasing stress, suggesting a potential shift in cost-benefit ratios and mycorrhizal function. Although mycorrhizal plants had higher photosynthetic rates (P=0.05) than non-mycorrhizal ones, this upregulation was insufficient to prevent reductions of shoot biomass when conditions were benign. Mycorrhizal plants also had higher stomatal conductance (P=0.01) and shoot water content (P=0.02), which is indicative of lower drought stress in general. Leaf water potential became increasingly negative with drought stress, especially in the most stressed non-mycorrhizal plants (PAMFxDrought