Reckless driving: Improved phosphorous availability is a most likely important driver and species killer in angiosperm evolution

Introductory summarizing paragraphPlants show a large range of genome sizes with a more than thousand fold difference between the largest and the smallest genomes (Bennett, M. D., 1972; Bennett, 2005; Knight, 2005; Gregory et al., 2007; Bai et al., 2012; Kelly et al., 2015). Since, 1. DNA phosphorous is a phosphorous pool not possible to recycle within the cell. 2. Carnivorous plants with very small genomes living in low phosphorous environments uses carnivory to supply phosphorous (Leushkin et al., 2013). 3. The genus Fritillaria with very large genomes is dependent on mycorrhiza (Wang & Qiu, 2006; Kelly et al., 2015) probably mainly for supply of P, I decided to investigate if lifestyles connected with releases from P-limitation correlate with 1C-genome sizes. For the investigation I used available lifestyle data from several websites and articles (Wang & Qiu, 2006; Lysak et al., 2008) together with the Angiosperm C-values available at Kew http://data.kew.org/cvalues/. Based on this analysis I suggest the following order of P restriction for genome size expansions, from the least restricted to the most restricted, for the different lifestyles: Myco-heterotrophs<Parasitic plants<Mycorrhizal plants<Non-Mycorrhizal plants<Carnivorous plants. The data further suggest that a general improved P status most likely precedes whole genome duplication events and that uneven ploidy increases are more punishing than even ploidy most probably since uneven ploidy increases cannot be followed by adaptive recombination/selection. Thus P-limitation is a likely main restraint for angiosperm evolution and genome-expansion. However, relaxing this restraint leads plants into an evolutionary dead end with large nuclei (Bennetzen & Kellogg, 1997) and high P demand.