CORESTA Meeting, Agronomy/Phytopathology, Louisville, 1991

Effects of abscisic acid and proline on adaptation to tobacco callus cultures to salinity and osmotic shock

EBERHARDT H.-J.
Verband des Cigarettenindustrie, Bonn, Germany.
Tobacco callus (Nicotiana tabacum cv. Badischer Geudertheimer) took up sorbitol rapidly and without a lag period from media with up to 0.7 M of the polyol. Accumulation of proline was greatly enhanced under these conditions and was proportional to the absorbed sorbitol, while the viability of the callus cultures was quite low after a few hours of incubation. Under moderate condition (0.1 M sorbitol) as well as under severe osmotic shock (0.8 M sorbitol), the cells adapted by adjusting the sorbitol/proline ratio to ca 3. NaCl (0.1 M) had the same effect as sorbitol (0.7 M) on the survival rate, but only slightly affected proline synthesis in the first hours of incubation. Addition of10-7 or10-5M abscisic acid (ABA) did not increase the proline content, but10-7M ABA delayed the deleterious effect of NaCl and improved the state of the cells. No influence of abscisic acid during the incubation with sorbitol could be detected. Two different strategies for the adjustment of tobacco callus to salinity and sorbitol are suggested : non-ionic stress is controlled by the accumulation of proline, whereas ABA could be involved in the adaptation to ionic stress.