The effects of gibberellic acid (GA(3)), kinetin (KIN), benzyladenine and ethylene (E) on mitotic activity and chromosomal aberrations in root tips of barley seeds (Hordeum vulgare L. cv. "Bulbul 89") germinated under salt stress were investigated. It was determined that all of these plant growth regulators (PGRs) decreased mitotic index in root tips of barley seeds germinated at 20 A degrees C and in distilled water. Furthermore, some of the PGRs studied increased significantly the frequency of chromosomal aberrations. The frequency of chromosomal aberrations in seeds treated with E and KIN was considerably higher than in the seeds germinated under nonstress conditions. The inhibitory effect of salt stress on mitotic index increased with increasing salt concentration (0.30, 0.35, 0.40 and 0.45 molal, m). GA(3) and KIN pretreatments showed a successful performance in ameliorating the negative effects of increasing salinity on mitotic activity. The number of chromosomal aberrations also increased with increasing NaCl concentration. However, most of the PGR pretreatments studied alleviated the detrimental effects of increasing salinity on chromosomal aberrations. KIN pretreatment at 0.30 and 0.35 m salinity could not rescued the cytogenetic activity of salt stress on this parameter.