Abstract
Genome size was estimated using Feulgen densitometry for 76 accessions of 40 taxa of Orobanche and two taxa each of the related
genera Phelypaea and Cistanche, providing the first data set for any group of nonphotosynthetic angiosperms. The 2C-values were
16.8-19.9 pg in Cistanche, 2.9-11.6 pg in Orobanche sect. Orobanche, 6.8-10.8 pg in sect. Trionychon, 4.3-5.1 pg in sect. Myzorrhiza,
and 4.9-5.8 pg and 10.5 pg in the two diploid species Phelypaea coccinea and P. tournefortii, respectively. Distribution of genome
size is congruent with phylogenetic lineages identified by analyses of nuclear ITS sequence data, in particular regarding the distinctness
of O. anatolica from the rest of sect. Orobanche. With the exception of tetraploid O. transcaucasica, polyploid taxa of sect. Orobanche
are among those with the smallest C-values, suggesting substantial genome downsizing after polyploidization (as in other angiosperm
groups). In O. sect. Orobanche, genome size evolved more rapidly in earlier stages of its evolution than in later stages. This might
be indicative of adaptive radiation, but this hypothesis requires corroboration in the form of genome size estimates on more taxa and
accessions.
| Original language | English |
|---|---|
| Pages (from-to) | 148-156 |
| Number of pages | 9 |
| Journal | American Journal of Botany: the journal for all plant biologists |
| Volume | 93 |
| Issue number | 1 |
| Publication status | Published - 2006 |
Austrian Fields of Science 2012
- 106012 Evolutionary research
- 106008 Botany