Mercury (Hg) is a heavy metal causing oxidative stress in plants. Saline soil in pots were treated with three levels of Hg (0, 75 and 150 mg/l) by using mercuric chloride salt 10 days after planting (plants at three leaf stage). The experiment was conducted as factorial in a completely randomized design with three replications. 60 days after planting, leaf samples were collected and investigated for photosynthetic pigments, soluble sugars, activity of peroxidase and catalase enzymes and chlorophylls a, chlorophylls b, total chlorophyll, SPAD value and carotenoids. Plants were harvested 70 days after sowing, and root and shoot fresh and dry weights and mercury concentration in root and shoot of turnip were determined. The results showed that the maximum concentration of mercury occurred in roots followed by shoots. Soluble sugars in shoot were reduced significantly, chlorophyll a, chlorophylls b, total chlorophyll contents and SPAD value were significantly reduced with 75 and 150 mg/l mercury treatments compared to control. Carotenoid content and catalase and peroxidase activities in leaf decreased significantly with mercury levels of 75 and 150 mg/l treatments compared to control. But shoots and roots dry weights were decreased with increasing mercury levels compared to control. Moreover, the TF value were <1 and BCF value >1.

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