CHARACTERISTICS OF STRESS-RESISTANT TOBACCO REGENERANTS

Regenerants resistant to the influence of 1% NaCl were obtained from 1 0 cell lines of Nicotiana tabacum L. previously selected for resistanc e to L-azetidine-2-carboxylic acid (a toxic analog of proline) and pos sessing overproduction of proline under stress conditions. Cells of th e leaves of regenerated plants were highly resistant to dehydration an d contained an enhanced amount of proline under normal as well as stre ss conditions. Regenerants of azetidine-resistant lines differed in sa lt tolerance, forms sensitive to salt influence being also found among them. Loss of salt tolerance by a regenerant is shown to be accompani ed by sharp decline in the level of free proline in its tissues. Secon dary callus induced from leaves of resistant regenerants preserved the trait of salt tolerance.