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Harvard Forest REU Symposium Abstract 2005

  • Title: Prey Availability Alters Photosynthetic Physiology in Sarracenia
  • Author: Cheryl L Hester (Pueblo Community College)
  • Abstract:

    Prey Availability Alters Photosynthetic

    Physiology in Sarracenia

    Cheryl Hester

    It has been widely accepted that there is a correlation between prey capture and photosynthetic rates among carnivorous plants; however, this theory has rarely been tested. This study expands the previous research by looking at a total of 10 species of pitcher plant, a majority of which have never been measured for photosynthetic rates. The theory predicts that the energy cost of producing a leaf that is specialized for the capture of prey (pitchers) versus a phyllode (photosynthetic leaf) is relative to the nutrient availability in the surrounding environment. If nutrients are limited the plants would devote more energy in producing pitchers for prey capture. Previous research had shown that this holds true for certain species when given an increase in inorganic nitrogen. I measured the photosynthetic rates and foliar chlorophyll prior to feeding the first and second pitchers; feeding treatments consisted of 6 weekly additions of 5 levels of ground insects along with a controlled unfed plant for each species. Minimum and maximum levels varied by average size of each species, resulting in a total of 9 levels across all species. At harvest, photosynthesis, fluorescence, chlorophyll, leaf area, and biomass were measured for the first, second, and an extra pitcher, along with a phyllode, if one was available. Photosynthesis (Fig. 1) and quantum efficiency both increased with amount of insects fed. The results support currently accepted theory; however, a longer-term study should be done to look at the delayed response of nutrient intake among pitcher plants.

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