The physiological responses of Dunaliella salina and Dunaliella tertiolecta isolated from Sambhar Salt Lake of Rajasthan, India were studied at different salinities. Both Dunaliella species (D.salina and D. tertiolecta) were treated with a range of NaCl concentrations from 6 to 30% (w/v). Salinity more than 15% decreased the growth rate and chlorophyll level in D. salina while increased the total carotenoid and glycerol level in the cell. In case of D. tertiolecta salinity more than 6% adversely affect the growth rate, while glycerol level was increased as salinity increased but total carotenoid and chlorophyll level was not salt triggered. The highest cellular carotenoids level in case of D.salina was recorded at 25% NaCl concentration. The results showed that glycerol level in both the species was salt induced.In case of D. salina maximum level of glycerol (30.5±0.24 pg/ cell) was at 30% salt concentration, while in case of D. tertiolecta (19.36±0.13 pg/cell) it was at 25% NaCl concentration. The highest specific growth rate in D. salina was observed at 15% NaCl (0.12 d-1), while in case of D. tertiolecta it was observed at 6% NaCl (0.13 d-1). These results indicated that D. salina was more salt tolerant than D. tertiolecta. Evaluation of physiological  attributes of these species will be of help for carrying out mass cultivation.

Dunaliella, salinity, growth rate, glycerol,carotenoids.