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Does endopolyploidy influence functional traits of Solidago
altissima leaves?
Kyle Snell
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.