EFFECT OF C-12(-BEAM IRRADIATION ON CELL VIABILITY AND PLANT-REGENERATION IN CALLUS, PROTOPLASTS AND CELL-SUSPENSIONS OF LAVATERA-THARINGIACA(5) ION)

The biological effects of irradiation with C-12(+5) ion beam on plant cells have been analyzed. Protoplasts and cell suspensions of Lavatera thuringiaca, and a somatic hybrid callus (Hibiscus rosa-sinensis + La vatera thuringiaca), were irradiated with doses from 0.05 to 50 Gy, an d the effects on cell growth, cell division, cell viability and embryo genesis rates were analyzed. Irradiation with C-12(+5) ion beam at rel atively very low doses (5.0 Gy) significantly inhibited cell division, yet the survival rate and regeneration capability of the cells throug h somatic embryogenesis were conserved in more than 70 and 50 %, respe ctively. These results indicate that cell division is the most sensiti ve parameter to irradiation, accounting for the inhibition of colony f ormation and callus growth. The potential use of the C-12(+5) ion beam in asymmetric protoplast fusion experiments is discussed.