In warmer habitats, plants possessing the C4 photosynthetic pathway have higher photosynthetic rates, greater potential productivity and greater competitive potential than the more common C3 species. The vast majority of C4 plants, including the economically important species such as corn and sugar cane, are limited to habitats which are worm and sunny. Since 1982, however, several species of the C4 grass Muhlenbergia have been discovered in forest understory habitats at light levels significantly lower than normal for C4 plants. This project investigates the photosynthetic responses of Muhlenbergia sobolifera, the most shade-tolerant C4 species known, to determine if it uses both photosynthetic pathways, either concurrently or in response to environmental cues. Because M. sobolifera is thought to have evolved regressively from the more common high-light, fully-functional C4 plants, an understanding of its metabolic pathway will provide scientists valuable insight into the environmental pressures which lead to the evolution of photosynthetic pathways. In addition, this knowledge may lead to breeding approaches for producing plants with the desirable characteristic of both photosynthetic types.
