Effect of Aldrin on Growth and Oxidative Metabolism of Rhizobia

At 500 μg ml⁻¹ of aldrin, Rhizobium sp. Bengal gram ( Cicer arietinum ) and Rhizobium sp. Green gram (Vigna radiata ) showed a lag of about 12 h after which the growth returned to normal. The lag period was extended at concentrations above 500 μg ml⁻¹ of aldrin and it was more in the case of Rhizobium sp. Green gram than Rhizobium sp. Bengal gram. However, at high concentrations of aldrin, after the lag, the growth rate was very slow. On the seventh day, Rhizobium sp. Bengal gram showed 72, 81 and 84° inhibition while Rhizobium sp. Green gram exhibited 74, 85 and 88° inhibition of growth at 1000, 1500 and 2000 μg ml⁻¹ of aldrin, respectively. In general, oxidative activity of both of the Rhizobium spp. on pentoses, hexoses and TCA cycle intermediates was more strongly inhibited in aldrin grown cells than normal cells. The inhibitory effect of aldrin on the oxidative activity of rhizobia was partially released with a high concentration of glucose.