effects of pgpr application methods on proline and soluble sugars content of yarrow (achilea millefolium l.) under drought stress conditions

in order to study the effects of pgpr application methods on proline and soluble sugars content of yarrow (achillea millefolium l.) under drought stress conditionsan experiment was performed at islamic azad university, yadegar-e-imam khomeini (rah) shahre-rey branch. this experiment was carried out in a split plot arrangement with randomized complete block design in three replications. experimental factors were included irrigation regimes as the main plot in three levels including 50, 90 and 130 mm evaporation from a class pan, and pgpr application methods in four levels including, non application, root inoculation, application in irrigation water, and root inoculation+irrigation in irrigation water methods as the subplot. the results indicated that, simple effects of irrigation and pgprs were significant on experimented traits but the interaction effects were meaningful only on proline content at 5% level of probability. in this case, drought stress increased proline and soluble sugars in yarrow. the treated plants with pgprs had lessproline and soluble sugars compare to control. the results revealed that root inoculation + application in irrigation water were more effective than without application methods for decreasing harmless effects of drought. so the lowest proline (2.0833 mg/g fw) belonged to non-stress and root inoculation+irrigation pgpr application methods treatment and the lowest soluble sugars (8.663 mg/g fw( belonged to non-stress and pgpr application in irrigation water methods treatment.