COS 303-1 - Temperature effect on enzyme concentration in two Sarracenia species

Abstract: Understanding how environmental conditions influence organismal physiological processes is of great importance in the context of climate change. Indeed, temperature and metabolism are directly linked. Sarracenia purpurea and Sarracenia flava are carnivorous plants that live in nutrient poor bogs, receiving most or all of their nutrients and minerals through predation on insects captured in their cup-shaped leaves (pitchers). These two species differentially rely on two different mechanisms of digestion. The pitchers of S. purpurea have a vertical lid and the contents are filled with rain water. These pitchers are habitat for bacteria, protists, invertebrates and more (inquiline community); so, S. purpurea relies more heavily on them for prey digestion. Sarracenia flava, on the other hand, have a horizontal lid and do not support as diverse an inquiline community, instead relying more heavily on plant produced digestive enzymes. In this study, we collect fluid from pitchers across ten sites varying in average temperatures across North Carolina and Virginia. We then used colorimetric enzyme assays to measure acid phosphatase, chitinase, and protease activity as a proxy for concentration. We use fluid enzyme concentrations to 1) understand the role of environmental temperature on nutrient release and 2) determine whether species specific enzyme concentration responds to temperature based on their digestive mechanism.

Our findings suggest that acid phosphatase (AP) concentration is inversely affected by the average temperature of the collection site. AP aid in phosphate release, a key limiting nutrient for carnivorous plants. Coupled with the understanding that enzymes function more efficiently in warmer temperatures, the overall inverse relationship suggests that pitcher plants in warmer areas are using AP more efficiently than plants growing in colder areas, thus producing a lower concentration. The AP results show that Sarracenia purpurea and Sarracenia flava are also affected differentially. As expected from its enzyme reliant carnivorous strategy, S. flava was significantly more affected by temperature. Unexpectedly, our results do not suggest any relationships between temperature and chitinase or protease activity. Overall, this study shows that temperature affects the nutrient processing in these pitcher plants negatively, but differentially depending on its digestive mechanism.