Kyle Snell

Does endopolyploidy influence functional traits of Solidago altissima leaves?

The significance of whole-organism polyploidy in plants has been hypothesized to increase the evolutionary potential due to the increased amount of replicate genomic DNA. Specifically, an increased amount of replicate DNA creates potential for unique gene expression patterns that would not be possible in a diploid. Recently, the significance of endopolyploidy, or “cell polyploidy,” in plants has begun to receive more attention. Endopolyploid cells contain at minimum a doubling of the base nuclear DNA of the plant, and have only been found in select tissues in plants exhibiting the phenomena. Based on the increase in cellular DNA, it has been hypothesized that endopolyploidy is an adaptive mechanism to enhance gene expression in specific tissue, rather than throughout the entire plant. This has specifically been hypothesized for plants with small genome sizes. One area that endopolyploidy may serve as an adaptive mechanism is in response to varying light quality, as instances of endopolyploidy have been correlated with a decrease in light quality. I propose an experiment to examine the occurrence of endopolyploidy though ontogeny in leaves of Solidago altissima, a native polyploid angiosperm that has been determined to exhibit endopolyploidy. The plants will be exposed to one of two light treatments inside of a growth chamber: one with light directly from the power compact bulbs inside the chamber, the other with the same light filtered to increase far-red wavelengths and simulate shade created by a neighboring plant. In addition I plan to measure four functional leaf traits: net photosynthetic rate, chlorophyll content, specific leaf area, and C:N ratio, and determine if a correlation exists between these traits and endopolyploidy. I hypothesize that S. altissima with smaller genome size will have higher instances of endopolyploidy than those with larger genome size. In addition, I hypothesize that increased endopolyploidy will have a positive correlation with chlorophyll concentration, net photosynthetic rate, specific leaf area, and a negative correlation with C:N ratio.