Genome size variation in gymnosperms under different growth conditions

Abstract

The genome is structurally and functionally influenced by ecological factors during adaptive processes. Several natural factors can cause this, and here we present the effects of different growth conditions on the genome size. Genome size assessments were carried out by flow cytometry for a set of 19 taxa for each of three growing conditions: (i) wild plants growing in their natural habitats used as a control group; (ii) potted plants; and (iii) bonsai plants. Our results show a large variation in the genome size of bonsai and potted plants compared to their wild representatives. The most important conclusion is that 1Cx values measured in potted plants can be up to 8.48% lower and in bonsai plants up to 26.83% higher than the values assessed for the respective wild individuals. In the case of Juniperus thurifera, this divergence largely exceeded the genome size variation previously estimated along the natural geographical range of the species. Such deviation from expected values could be interpreted as genuine genome size variation, or to result from biochemical or/and DNA compactness changes triggered by growth conditions. The present results provide evidence for plant response to human-induced environmental changes, thus making the current approach potentially interesting for the prediction of the influence of climate change on plants and for other applications.