Genome Size and DNA Base Composition of Geophytes: the Mirror of Phenology and Ecology?
|Year of publication||2011|
|MU Faculty or unit|
|Description||Genome size is known to affect various plant traits such as stomatal size, seed mass, and flower or shoot phenology. However, these associations are still not well understood for the species with giant genomes, mostly represented by geophytic plants. No detailed associations are known between DNA base composition and genome size or species ecology. Genome sizes and GC contents were measured using flow-cytometry in a worldwide sample of geophytes together tentative morpho-anatomical and ecological traits. Data were analyzed using conventional statistics and using analysis of phylogenetically independent contrasts. Increase in genome size was associated with earliness of flowering, tendency to grow in humid conditions, and tightly positively correlated with increase in stomatal size, namely in extremely large genomes. Seed mass of geophytes was closely related to their ecology, but not to genomic parameters. Genomic GC content showed unimodal relationship with genome size but no relation with species ecology. Evolution of genome size in geophytes is closely related with their ecology and phenology and also associates with remarkable changes in DNA base composition. While geophytism together with producing larger cells seems advantageous strategy for fast development of an organism in seasonal habitats, this is perhaps the drought sensitivity of large stomata which restrict the occurrence of geophytes with giant genomes to water non-stressed conditions.|