Summary Two cultivars of barley, Prato and California Mariout 72 (CM 72), show significant differences in response to salt stress during seed germination (Ramagopal, 1988). Seeds of these cultivars were imbibed in germination-inhibitory concentrations of salt, 0.34M NaCI (Prato) and 0.51M NaCI (Prato and CM 72), for 3 days; the ungerminated seeds were selected and further incubated for 24 h in a nonsaline medium, at which time the seeds were on the verge of germination. The embryos were labeled in vivo with 35S-methionine and protein synthesis was assayed during salt stress and recovery. The embryos of both cultivars retained their ability to incorporate 35S-methionine into protein under prolonged stress. The salttolerant cultivar (CM 72) showed a higher capacity to resume protein synthesis than the salt-sensitive cultivar (Prato) upon removal of salt. Newly synthesized proteins were analyzed by sodium dodecylsulfate- polyacrylamide gel electrophoresis, fluorography, and densitometry. Although some of the proteins made during salt stress and recovery were common, distinct differences were also observed. Eight new proteins were made exclusively during salt stress and seven during recovery. All of the newly induced proteins in CM 72 and Prato were qualitatively identical, but the expression of some of them indicated that quantitative differences existed between the two cultivars. Further, the protein profiles of recovering seed embryos were distinctly different from those of germinating embryos not previously exposed to salt. The findings suggest that prior salt stress alters the pattern of proteins normally associated with the germinating embryos.