Absorbability and translocation of Nickel from soil using the sunflower plant (Helianthus annuus)

Today, soil pollution with heavy metals is a major environmental concern across the world. Phytoremediation is defined as a technique through which plants are able to absorb contaminants and potently recover the soil that is polluted by heavy metals. The present study aimed to investigate the level of nickel concentration in the roots, stems, and leaves of sunflower, as well as the mobility of this heavy metal in the organs of the plant. Various concentrations of nickel nitrate (50, 100, and 200 mg/kg) were added to the soil in the form of solutions. After the growing season, samples of the plant organs and corresponding soils were collected in order to measure the total concentration of nickel. According to the results, the highest concentration of nickel at the treatments of 0, 50, and 100 was detected in the stem, while the highest concentration in 200 mg/kg was detected in the roots. The lowest concentration of nickel was observed in the leaves in all the treatments. In addition, the measurement of the nickel mobility in various layers of the soil samples indicated that this index was above one only in the soil to the root layer (200 mg/kg) and root to the stem in the other treatments, which denoted the high translocation of this metal in the mentioned layers. Considering the risk of nickel toxicity, it seems that sunflower accumulates the highest level of nickel in the root and sending the lowest one to the shoot at high concentrations in soil.