Germination and Seedling Growth of Coriandrum sativum L. Under Varying Levels of Mixed Cadmium and Copper

Elevated levels of heavy metals in contaminated soils are widely spread and concerns have been raised over the potential risks to humans, animals and agricultural crops. This study was conducted to evaluate the effect of mixed cadmium and copper on seed germination and seedling growth of coriander. Treatments were 0 (control), 25, 50, and 100 mg/kg which were made by equal amounts of cadmium (1/2) and copper (1/2). From the data obtained in the presence of different concentration of metals, Germination Index (GI), Metal Tolerance Index (MTI), and Percent Phytotoxicity was calculated. Increasing the concentration of heavy metal mixture to 100 mg/kg showed a significant decrease in seed germination as compared to control treatment (p<0.01). Heavy metal mixture concentrations of 25 mg/kg increased seedling fresh and dry weight (p<0.01) as compared to control. However, the heavy metal mixture concentration of 100 mg/kg produced the lowest amount of both seedling fresh and dry weight. A negative response of root and shoot length of coriander to heavy metal mixture application relative to control treatment was observed at 100 mg/kg (p<0.01). The study suggests that cultivation of coriander in metal polluted soils should be avoided or appropriate control measures be adopted to maintain the heavy metal content of the soil below the damage threshold level.