The Consequences of Whole Genome Duplication in Arabidopsis thaliana

Abstract

Whole genome duplication, having more than two chromosome sets per nucleus is found in all domains and kingdoms, but is especially frequent in plants. In this thesis, I examined the structural consequences of whole genome duplication, its impact on storage and growth, and its associations with environment through an analysis of natural diploid and synthetic polyploid accessions of Arabidopsis thaliana that differed in tissue endopolyploidy. I found that leaf endopolyploidy positively correlated with apparent chlorophyll content; possibly indicating that endopolyploidy increases the chloroplast content of leaves. I also found that leaf endopolyploidy increases in colder environments; possibly as a way to increase growth speed. Moreover, I found that polyploidy increases the storage/water content per unit dry mass of tissues and organisms which may increase their tolerance to drought. However, increasing cytotype may come with costs such as increased days to bolting, decreasing seed production and a decrease in structural stability. A novel equation/model quantifying the changes in tissue storage from whole genome duplication was proposed. This equation/model may be applied to other organisms in order to better understand the variation in incidence of whole genome duplication among different taxonomic groups.