Comparison of Fine and Coarse Rice Varieties for Nickel Accumulation and Growth Response at Different Levels of Nickel

The differential growth response and nickel (Ni) accumulation by two rice varieties grown in Ni-contaminated soil are investigated. Soil is contaminated with Ni at different levels viz. control (0), 7, 15, 22, 30, and 38 mg kg???1 soil. Two rice varieties viz. Basmati-2000 (fine variety) and KSK-133 (coarse variety) are grown in pots containing Ni-contaminated soil. The plants are harvested at four growth stages with an interval of 15 days. Harvested plants are washed with distilled water to remove aerial deposition. Harvested plants are oven-dried, weighed, grinded, and digested with di-acid mixture. The digested samples are analyzed for Ni, zinc (Zn), and manganese (Mn) concentration. The results indicate that the maximum level of Ni (38 mg kg???1) inhibits the shoot and root growth. The maximum shoot and root dry weights are observed at lower level of Ni, that is, 7 mg kg???1. The concentration of Ni in plants increases with increasing Ni levels compared to control while the concentration of Zn and Mn decreases with increasing Ni levels. The maximum concentrations of all elements are recorded at the first harvest which gradually decrease in the subsequent harvests. It is concluded that Basmati-2000 is tolerant to Ni toxicity compared to KSK-133.