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Abstract

The hybrid cattail Typha × glauca is invasive in the Midwestern United States, and outcompetes wetland natives and its parent species, Typha angustifolia and Typha latifolia under high nutrient conditions. Typha × glauca’s large size and copious litter production are the main factors known to contribute to its success, although research is lacking on physiological processes that contribute to its nitrogen use efficiency.

Nitrogen resorption was investigated as a mechanism of dominance in Typha × glauca. Due to nitrogen resorption being a nutrient conservation strategy, nitrogen resorption should be high in areas of low nitrogen availability. Since nitrogen resorption is an energetically-costly process, we hypothesized that Typha × glauca would exhibit lower nitrogen resorption than either parent species, thereby not wasting energy on unnecessary nutrient conservation in the nutrient-rich environments where it is dominant. Nitrogen resorption was evaluated in Typha × glauca and its parent species across a nutrient gradient. Our results showed significant differences in resorption across the nutrient gradient; in areas of high nutrients nitrogen resorption was lower. However, resorption did not differ significantly between taxa. This suggests that nitrogen resorption is not a primary factor in Typha × glauca’s success.

Producing longer-lived leaves also conserves nutrients but decreases photosynthetic capacity. Because of this, we hypothesized that Typha × glauca would have a shorter leaf lifespan and a higher photosynthetic rate than its parents because in high nutrient areas competition is mainly for light and nutrient conservation is less advantageous. Leaf longevity and photosynthetic rate were measured in Typha × glauca and its parent species across a nutrient gradient. Our results showed that leaf longevity did not differ between the three taxa or across a nutrient gradient. Photosynthetic rate differed between taxa; T. angustifolia exhibited the highest rates followed by Typha × glauca and T. latifolia. These results show that photosynthetic rate may be playing a role in Typha × glauca’s dominance over T. latifolia, but not T. angustifolia. There were significant differences in photosynthesis across a nutrient gradient with high soil nitrogen levels having the highest rates.

Year of Submission

2018

Department

Department of Biology

First Advisor

Kenneth Elgersma

Date Original

2018

Object Description

1 PDF file (VI, 61 pages)

Language

EN

File Format

application/pdf

Included in

Plant Biology Commons

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