Nitrogen Resorption in Cattail Species: Are There Differences?

T. x glauca is an invasive hybrid cattail that is prevalent in the Midwestern United States. Under high nutrient conditions, T. x glauca can outcompete native wetland species, including other cattails. T. x glauca’s large size and copious litter production are the main factors known to contribute to its success, although research on physiological processes, such as nitrogen resorption, is lacking. Nitrogen resorption is an important nutrient conservation strategy that utilizes energy to move nitrogen from senescing leaves to storage tissues. Theory suggests that nitrogen resorption should be high in areas of low nitrogen availability, where resorption provides a large competitive advantage. We hypothesized that T. x 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. This study evaluated nitrogen resorption in T. x glauca and its parent species, T. angustifolia and T. latifolia across a nutrient gradient. Live and senesced leaf tissue samples from each taxon were analyzed for their nitrogen content. Our results confirmed that there were significant differences in resorption across the nutrient gradient. In contrast, resorption did not differ significantly between species. This suggests that nitrogen resorption is not a primary factor in T. x glauca’s success. Consequently, lowering nitrogen levels in waterways may not be an effective management plan on its own, since T. x glauca may be able to recycle nitrogen as effectively as its parent species