Small vs. large

Traits of organisms are in the limelight of contemporary ecological research. Traits can be different features of organisms, such as size or weight, but also biochemical processes or concentrations of certain substances in cells and tissues. Scientists are particularly interested in understanding the functions of a given trait and how traits, the environment, individual organisms and their fitness, the diversity of species, and ultimately the functioning of entire ecosystems are interrelated. The aim of this research project is to study in plants the relationship between two important traits: genome size and growth rate. Genome size is the total amount of DNA contained in the genome of an organism. Genome size is known to vary greatly across organisms, but it does not necessarily reflect the complexity of a given species. Scientist found, however, correlations between genome size, cell size, metabolic processes within cells, and the pace at which cells divide. Based on these correlations it is generally assumed that with increasing genome size of organisms their growth rate, i.e. the increase of biomass (weight) over time, decreases. This assumption is controversially discussed because studies revealed contrasting results. However, recent plant-studies suggest that the relationship between genome size and growth rate could be dependent on the availability of mineral nutrients, key resources of plant growth. Paramount goal of this research project is to specifically test this novel idea. To this end a series of plant growth experiments, applying different fertilization treatments, with 140 plant species will be conducted. Besides different genetic and biochemical analyzes, phylogenetic comparative analyses will be used to test for potential underlying evolutionary correlations. In plants it is common that an organisms genome contains more than two copies of chromosomes, which is called polyploidy. Understandably a higher copy number affects genome size; hence, this research project also aims to elucidate which is more important for plant growth, the absolute genome size or the level of ploidy, respectively. Taking only a few traits into account, this research project has the potential to uncover a hitherto unexplored and possibly fundamental ecological concept. This is, a concept that may help us to better understand our environment, but also protect it. The latter appears particularly important when we consider the enormous impact of humans on the inputs of nutrients to diverse ecosystems and the resulting changes of those systems.