Chromosome number and nuclear DNA content of plants regenerated from salt adapted plant cells.

Plants regenerated from tobacco (Nicotiana tabacum L. cv. Wisconsin 38) cells that were adapted to 428 mM NaCl were found to have hexaploid or near-hexaploid chromosome numbers compared to the normal tetraploid, 2N(2C)=4X=48 chromosome numbers of plants regenerated from unadapted cells. Even though cells with chromosome numbers other than hexaploid were found in the cell population only hexaploid plants were regenerated. The hexaploid condition may impart some karyotypic stability that allows more efficient morphogenic activity. The hexaploid condition could not be correlated with several phenotypic alterations associated with plants regenerated from adapted cells, including male sterility and increased salt tolerance.