Effect of metal stress condition on life period of different varieties of rice

In the present investigation, experiments have been designed to study the effects of different concentrations of Cd, Pb and Hg on life periods of 14 different varieties of rice (viz., Annapurna, MW 10, Swarna, IR 52, Ratna, IR 36, Mashuri, Kunti, Parijat, Pusa-2-21, IR 42, Samlai, Pankaj, Assam Aus). Three different concentrations of Cd, Pb and Hg, i.e. 1 ppm, 3 ppm and 5 ppm were used for treatment. Treatment with Cd, Pb and Hg salt solutions started after transplantation of the plants and continues for several times at intervals to cover the period of growth from 45 days 10 boot leaf stage. Then flowering time and maturity were noted for treated and control plants. It was found that life period was affected, i.e. either increased or decreased in some varieties, but others were not effected.