Salicylic acid (SA) plays a key role in plant disease resistance and hypersensitive cell death but is also implicated in hardening responses to abiotic stressors. The aim of this study is to examine the effects of salicylic acid on the growth, eco-physiological and biochemical characteristics in Zinnia eleganceplant exposed to copper stress. Effects of copper (Cu) on biomass, root length and shoot height and Cu uptake are also discussed. This experiment was arranged as a factorial experiment based on completely randomized design with four replications in greenhouse conditions. The experimental treatment consisted of four levels of Cu (0, 100, 200, and 400 mg kg-1 in potted soil) and three levels of salicylic acid (0, 1, 2mM) as foliar spray or chelate into soil. Results showed that with increasing levels of copper, reductions in shoot and root growth, leaf area and leaf number were statistically significant at 1 percent level. Analysis of some biochemical indices (chlorophyll content) and eco-physiological indices such as primary florescence chlorophyll (Fo), ratio of variable chlorophyll to maximum (Fv/Fm) in treated plants were statistically significant at one percent level. The results showed that copper accumulation was higher in the roots than shoots. The Fluorescence measurements showed that primary florescence chlorophyll (Fo) was increased butFm wasdecreasedprogressively with increasing Cu. Salicylic acid significantly increased root and shoot growth, chlorophyll in copper stressed plants.SA treatments as chelate in concentration of 2mM also showed an increased level of tolerance toward high Cu concentrations as indicated by chlorophyll fluorescence parameters. The results support the conclusion that SA alleviates Cu toxicity.

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