Abstract Detail

Recent Topics Posters

Horner, John [1], Schatz, Benjamin [1].

Resorption of trap nitrogen during senescence and a nitrogen cost-benefit analysis of prey capture in a carnivorous pitcher plant.

Previous cost-benefit analyses of botanical carnivory have focused primarily on energy, but the principle benefit of carnivory is the acquisition of limiting nutrients such as nitrogen (N) for use in various physiological processes. In assessing the nutrient costs and benefits of carnivory, nutrient resorption during senescence could substantially alleviate the cost of constructing traps and affect the nutrient cost-benefit relations of prey capture. Since carnivorous plants generally grow in nutrient-poor soils, we hypothesized that nitrogen resorption during senescence should be relatively efficient. We further hypothesized that the resorption of nitrogen should reduce the nitrogen irretrievably committed to the production of the trap, which in turn would minimize the N needed from prey capture to achieve marginal return. We performed a field study in which we compared the N content of non-capturing mature pitchers, of non-capturing senescent pitchers after resorption, and of prey capture. Although the % N (dry mass) of senescent pitchers was lower than that of green pitchers, this difference was not statistically significant.  However, this was due to a significant resorption of nontarget components of the pitchers as revealed by a change in the specific leaf mass (mass per unit area) of pitchers. Another measure of N content, the N per unit area of pitchers, was significantly lower in senescent than in mature green pitchers.  The resorption efficiency based on N/unit area was approximately 42%. The cumulative mass of N captured per unit area was significantly less than the N/unit area of mature pitchers but was comparable to that in senescent pitchers. Therefore, prey capture offset the N content of senescent pitchers but may not offset the N content of green pitchers. Resorption reduces the N needed from prey capture to achieve marginal return, which supported our second hypothesis.

1 - TCU, Biology, Box 298930, 2955 S. University, Fort Worth, TX, 76129, USA

Keywords:
Carnivorous plant
Sarracenia
cost-benefit analysis
Nutrient reabsorption.

Presentation Type: Recent Topics Poster
Session: P
Location: Hall D/The Shaw Conference Centre
Date: Monday, July 27th, 2015
Time: 5:30 PM
Number: PRT043
Abstract ID:1829
Candidate for Awards:None