ABSTRACT Plants play an essential role in the ecological cycle; however, they face numerous global biotic and abiotic stress factors. The capacity of plants to survive in adverse conditions is called stress tolerance. Drought stress is among the major stresses faced by plants, as arid conditions affect plant development and productivity, crop yield, relative water content, nutrient intake, photosynthesis, dry matter accumulation, and respiration. Hormones play an essential role in plant stress metabolism. Until recently, it was thought that plant hormones consisted of five groups: auxin, gibberellin, cytokinin, abscisic acid, and ethylene. However, other substances synthesized by plants, such as jasmonates, brassinosteroids, salicylic acid, and nitric oxide, have also shown critical vital functions in the plant, like the hormones. Another hormone in these substances is strigolactone (SL), which has been reported to perform essential functions in stress physiology. This research investigated the effects of SL applications on drought stress on 1103 Paulsen American Grapevine Rootstock. GR24, a synthetic analog of SLs, was applied to grapevine rootstock. Physical and biochemical changes were determined (chlorophyll, membrane injurity, prolin, lipid peroxidation, soluble protein, superoxide dismutase, ascorbate peroxidase activities, phenolic compounds, plant hormones, and mineral elements). The results show that GR24 applications effectively alleviate the harmful effects of drought stress in most features. cycle however factors tolerance productivity yield content intake photosynthesis accumulation respiration metabolism recently groups auxin gibberellin cytokinin acid ethylene However jasmonates brassinosteroids oxide SL, , (SL) physiology 110 Rootstock GR SLs rootstock chlorophyll, chlorophyll (chlorophyll injurity prolin peroxidation protein dismutase activities compounds elements. elements . elements) GR2 features (SL 11 1