Genome size in the UK Fabaceae flora and how this relates to their nitrogen and water tolerance - Royal Botanic Gardens, Kew research repository
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Master's dissertation

Genome size in the UK Fabaceae flora and how this relates to their nitrogen and water tolerance

2019

Abstract

Genome size (GS) is defined as the total DNA amount in the unreplicated nucleus of an organism, often used synonymously with ‘1C value’. GS varies greatly in flowering plants. Nitrogen (N) and water are considered major limiting factors for plant growth, and their availability could correlate with plants’ GS. Nitrogen is one of the main building blocks of DNA; plants with larger genomes may have elevated N requirements. Water is lost through pores in the epidermal leaf surface area called stomata, formed by two guard cells. GS has been shown to positively correlate with guard cell size. Previous studies have demonstrated that smaller guard cells result in reduced water-loss. This study considers whether large genome Fabaceae species are more likely to be excluded from dry, N-limited environments, and whether there is an interaction between N and water availability which affects GS. Ellenberg values were used as a proxy for water and N in habitats. GS of UK Fabaceae flora were obtained from the Royal Botanic Gardens, Kew 2C-value database and flow cytometry measurements. Guard cell measurements were obtained from stomatal peels. Statistical analysis in R revealed statistically significant correlations between genome size, water, nitrogen and their interaction, with one interesting outlier species. Phylogenetic trees, ancestral reconstruction and a phylogenetic least squares model revealed a strong phylogenetic signal in the data. This study demonstrates that N and water availability often has an effect on GS in UK Fabaceae. Subsequent studies should include mycorrhizal association and

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2019_Pollitt_Lauren_MSc.pdf
30 Apr 2020
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