Abstract: Present work studied physiological and biochemical characteristics of Scytonema javanicum,one of the pioneer species that was isolated from algal crusts.The production of extracellular polymeric substances(EPS) and carbohydrates increased by exponential growth phase and reached maximum in stationary phase.Under salinity,the growth rates were restrained and biomass production was decreased,wherever,the productions of EPS and proteins were increased.In the presence of NaCl concentration,the intracellular deoxidizing sugar,water-soluble sugar and sucrose were increased and reached maximum at 0.1 mol·L^-1.The grapes of the proline production have a typical V shape with various salinities.Pigment analysis showed that the absorbance carotenoid had a significant change,whereas Scytonemin pigment changed a little under salt stress.The increase of EPS and the changes of intracellular carbohydrates under salt stress showed that they changed the equilibrium between intra-and extra-cells and played an important role in osmotic regulatory.

Key words: desert algae, salt stress, extracellular polymeric substances(EPS), photosynthetic character