Effects of Gamma Rays and Sodium Chloride on Growth and Cellular Constituents of Sunflower (Helianthus Annuus L.) Callus Cultures

The effect of gamma rays and NaCl on growth and cellular contents of soluble carbohydrates, protein and nucleic acids in Helianthus annuus L. callus were investigated. Optimal callus initiation was attained in stem segments cultured in MS medium enriched with 0.05 mg/1 2,4-dichloro phenoxyacetic acid (2,4-D) and 0.01 mg/1 N-6 furfurylamino purine (kinetin). Radio sensitivity, based on fresh weight changes, was determined following exposure of the calli to different doses of gamma rays. The LD50 was calculated and it was equal to 2.8 krad. Inclusion of NaCl in the medium caused a significant reduction in callus fresh weight. In general, the cellular contents of protein, soluble carbohydrates and ribonucleic acid (RNA) were reduced, while deoxyribonucleic acid (DNA) increased at 2% NaCl level. There is a significant increase in protein, carbohydrates and DNA, while a significant reduction in RNA content was observed. The role of such information in breeding for salt tolerant sunflower following physical mutagenesis in vitro is outlined.