This study was conducted to investigate the influence of ACC deaminase rhizobacteria on the ACC-induced classical "triple" response in etiolated pea seedlings. Etiolated pea seedlings were exposed to different concentrations of ACC (0, 2, through 10 mmol L-1), in 100 ml glass beakers placed in airtight mason jars wrapped in green foil and incubated under dark for seven days. In another study pea seedlings were inoculated with five strains of rhizobacteria which vary in their ACC-deaminase activity. These inoculated pea seedlings were exposed to 10 mmol L-1 ACC and incubated in the darkness at 25 ± 3 ºC. Results revealed that exogenous application of ACC had