PHYSIOLOGY OF NACL TOLERANCE IN CALLI OF VIGNA-RADIATA (L) WILCZEK

Calli of two strains of Vigna radiata, CUM 82007 and CUM 82037 were cultured on the callus proliferation medium (MS + 2.0 mg l-1 BA + 0. 2 mg l-1 NAA) in presence of NaCl concentrations ranging from 0 to 150 mM. Calli of CUM 82007 exhibited salt tolerance upto 100 mM NaCl(ext) while CUM 82037 was susceptible to salinity at this concentration. Presence of NaCl in the medium affected various growth parameters differently of the Calli of the two strains. Correlation coefficients between external and internal Na+ concentrations with various growth parameters as well as soluble sugars and proline contents revealed that proline is a better stress marker than sugars and it accumulates in the cells possibly to withstand situation of salinity stress. However, the salt tolerant strain accumulates relatively less proline than susceptible one. Free sugars appear to have a more important role in salt tolerance of the legumes.