Physiological and biochemical responses induced by Nickel to plants growing at nickel polluted soil

Abstract

An experiment was conducted in three different plants like a cereal crop plant [Oryza sativa L.], an oil yielding plant [Arachis hypogea L.] and a pulse crop plant [Macrotyloma uniflorum (Lam.) Verdc.] to assess the effect of nickel on seed germination, growth and biochemical parameters. The seeds of all the test plants were germinated in six different concentrations of Nickel chloride solution ranging from 0.0 to 100 mg/l of nickel. It was observed that seedling vigour index, metal tolerance indices were decreased and the percentage of phytotoxicity was increased with increasing level of nickel. The pot culture experiment revealed that, the growth parameters and the percentage of moisture content in plant were reduced with increase in concentration of nickel and in contradiction, seedlings exhibited better result in terms of growth in 40 ppm of nickel at 30^th day (developmental stage) and 100^th day (matured stage) of treatments thereby indicating that Nickel at or below 40 mg/kg had stimulating effect on the seedling growth. Similarly the total chlorophyll content, total soluble protein content were decreased although free proline content was increased with increase in concentration of nickel at 30^th day (developmental stage) and 100^th day (matured stage) of treatment.  Hence, it could be concluded that Nickel at lower concentration had an inducing effect on plant growth and inhibited the same at higher concentrations.