The Effects of A Plant's Water
Requirement on RuBisCo Levels
Abstract
Rubisco is an enzyme that facilitates carbon fixation in the photosynthesis cycle of plants. Photosynthesis is one of the most important processes in life, therefore it is important to understand all the key components like rubisco. Studies have shown that plants that are drought resistant do not use as much rubisco, therefore, it is predicted that the less water a plant requires, the less rubisco the plant will produce. Thus plants from a desert origin, purslane, a moderate climate, lavender, and an aqueous environment, water lettuce, were chosen to study the effect of water requirement on rubisco protein and RBCL DNA levels. Therefore it is believed that purslane will have the least amount of RBCL DNA along with rubisco protein than either lavender or water lettuce. In addition, water lettuce will have the most RBCL DNA and rubisco protein. Real Time PCR was used to determine the amount of RBCL DNA, the gene for rubisco, encoded within samples. In addition, a Western Blot was used to determine the amount of rubisco protein itself within the plant. The Real Time PCR revealed a lower amount of RBCL DNA for purslane than both water lettuce and lavender which had similar amounts of RBCL DNA. The Western Blot only showed bands of rubisco protein for lavender. This may be that the other protein concentrations were too low to visualize. The Real Time PCR supports the hypothesis that a plant that needs little water to survive, such as drought resistant purslane, have less RBCL DNA than either a mesophyte or aquatic plant. However, the Real Time PCR also shows that the mesophytic lavender had about the same amount of DNA as the aquatic water lettuce. The Western Blot would need to be performed again to be used to confirm this data or show evidence that amount of rubisco is different that the amount of RBCL DNA.
Authors: Sarah Davis and Rebecca Moore
James Madison University Biology Department
Image courtesy of: Protein Data Bank