Table II.
rDNA cytosine methylation in leaf and derived calli
The calli were established from different plants and cells were cultivated for at least 6 weeks. In all experiments, the growth media contained the same concentration of auxin and cytokinin. N, Number of independent experiments; nd, not determined.
| Species | Methylation of the 18S Genea | Methylation of the IGSb | |||
|---|---|---|---|---|---|
| N | Leaf | Callus | Leaf | Callus | |
| N. tabacum cv Vielblattriger | 5 | 91 ± 5.0 | 71 ± 4.7 | 72 ± 8.2 | 42 ± 10.0 |
| N. tabacum cv SR-1 | 4 | 76 ± 3.0 | 63 ± 3.0 | 45 ± 2.4 | 33 ± 5.7 |
| N. sylvestris | 3 | 96 ± 0.6 | 80 ± 2.4 | 96 ± 0.3 | 90 ± 0.6 |
| C. parqui | 2 | 98 ± 0.3 | 94 ± 0.3 | Nd | nd |
| T. mirus | 1 | 98 | 95 | Nd | nd |
a
The data are based on methylation of a conserved SalI site close to the 5′-end of the 18S gene.
b
The data are based on methylation of ClaI and MspI sites in the ETS of N. tabacum and N. sylvestris, respectively.