Assessing the Role of UV-B Radiation and Litter Position on UV-Absorbing, Bulk-Soluble Phenylpropanoid Concentrations in Typha angustifolia

Location

CSU Ballroom

Start Date

10-4-2018 10:00 AM

End Date

10-4-2018 11:30 AM

Student's Major

Biological Sciences

Student's College

Science, Engineering and Technology

Mentor's Name

Christopher Ruhland,

Mentor's Department

Biological Sciences

Mentor's College

Science, Engineering and Technology

Second Mentor's Name

Erin Moseman

Second Mentor's Department

Biological Sciences

Second Mentor's College

Science, Engineering and Technology

Description

Plant phenylpropanoids are secondary metabolites produced via the Shikimate Pathway and act as a protective sunscreen for terrestrial and aquatic plants. These phenolics are essential in deterring herbivory, pathogen-attacks and inhibiting decomposition. Narrow-leaf cattail (Typha angustifolia) is an emergent, invasive hydrophyte prominent in Minnesota's wetlands. Decomposition of cattail is a major contributor to biogeochemical cycling in these systems. Therefore, understanding how this material breaks down is important for quantifying carbon fluxes in wetlands. Senescent litter persists throughout the winter months when microbial decomposition is presumably low and limited by temperature. Litter is exposed to sunlight throughout the season and how visible and ultraviolet (UV) radiation influences the breakdown of this material is unknown. We examined how concentrations of bulk-soluble UV-absorbing phenylpropanoids in cattails changed over time when exposed to near-ambient and reduced UV irradiance. We compared litter placement (standing vs. fallen), as much of this material is lodged during winter months. Litter was placed in bags that either transmitted 85 (“Aclar”) or 2.8% (“Mylar”) of ambient ultraviolet-B radiation (UV-B) for 225 d. Concentrations of phenylpropanoids were measured spectrophotometrically at 300 and 375 nm. Over the course of the experiment, litter lost significant amounts of soluble phenolics and on average, standing litter lost 19% more of these compounds than fallen litter. Standing litter placed in Aclar bags lost 53% of their initial phenolics, which was higher than all other treatments. Exposure to UV-B, especially during the winter months, may prime litter for leaching of bulk-soluble compounds.

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Apr 10th, 10:00 AM Apr 10th, 11:30 AM

Assessing the Role of UV-B Radiation and Litter Position on UV-Absorbing, Bulk-Soluble Phenylpropanoid Concentrations in Typha angustifolia

CSU Ballroom

Plant phenylpropanoids are secondary metabolites produced via the Shikimate Pathway and act as a protective sunscreen for terrestrial and aquatic plants. These phenolics are essential in deterring herbivory, pathogen-attacks and inhibiting decomposition. Narrow-leaf cattail (Typha angustifolia) is an emergent, invasive hydrophyte prominent in Minnesota's wetlands. Decomposition of cattail is a major contributor to biogeochemical cycling in these systems. Therefore, understanding how this material breaks down is important for quantifying carbon fluxes in wetlands. Senescent litter persists throughout the winter months when microbial decomposition is presumably low and limited by temperature. Litter is exposed to sunlight throughout the season and how visible and ultraviolet (UV) radiation influences the breakdown of this material is unknown. We examined how concentrations of bulk-soluble UV-absorbing phenylpropanoids in cattails changed over time when exposed to near-ambient and reduced UV irradiance. We compared litter placement (standing vs. fallen), as much of this material is lodged during winter months. Litter was placed in bags that either transmitted 85 (“Aclar”) or 2.8% (“Mylar”) of ambient ultraviolet-B radiation (UV-B) for 225 d. Concentrations of phenylpropanoids were measured spectrophotometrically at 300 and 375 nm. Over the course of the experiment, litter lost significant amounts of soluble phenolics and on average, standing litter lost 19% more of these compounds than fallen litter. Standing litter placed in Aclar bags lost 53% of their initial phenolics, which was higher than all other treatments. Exposure to UV-B, especially during the winter months, may prime litter for leaching of bulk-soluble compounds.

Recommended Citation

Schmid, Samuel. "Assessing the Role of UV-B Radiation and Litter Position on UV-Absorbing, Bulk-Soluble Phenylpropanoid Concentrations in Typha angustifolia." Undergraduate Research Symposium, Mankato, MN, April 10, 2018.
https://cornerstone.lib.mnsu.edu/urs/2018/poster-session-A/20