Cellular and whole plant responses ofVigna radiata to NaCl stress

The effect of different NaCl regimes was examined on the growth and ion accumulation in whole plants and callus cultures ofVigna radiata. Whole plants grown in sand culture were watered with Hoagland's solution supplemented with 0-350 mol m-3 of NaCl. Callus cultures were initiated from leaves of 7-d old seedlings of the same seed stock and grown in modified PC-L2 medium containing the same levels of NaCl as in Hoagland's solution. Callus showed the same tolerance to salt as did the whole plant suggesting thatV. radiata appears to have a mechanism(s) for salt tolerance which operates at the cellular level. Ion analysis of whole plant showed that root sodium concentrations of the tolerant cultivar G-65 was much higher while shoot sodium was much less than those of salt sensitive cultivar ML-1. Callus cultures of cv. G-65 also accumulated higher Na+ levels. Thus, the greater salt tolerance of cv. G-65 was associated with the control of sodium accumulation at the shoot or cellular level.