Effect of Enhanced Lead and Cadmium in soil on Physiological and Biochemical attributes of Phaseolus vulgaris L

Phaseolus vulgaris L. plants were grown in soil supplemented with different Pb and Cd concentrations (2, 4, 6, 8 gKg for Lead and 1.5, 2.0, 2.5, 3.0 gKg for Cadmium). Germination % was remained unaffected at low concentration of both metals as compared to control plants but at higher concentration of Cd i.e. 3g/Kg soil, germination was completely inhibited. Growth was also decreased as concentration of metals was increased as compared to control plants. Photosynthetic pigments, total soluble sugar, starch content as well as soluble protein content decreased as concentration of metals was increased in comparison of control plants. However, total free amino acid content and lipid peroxidation were increased with increasing concentration of heavy metals. Electrophoretic studies revealed that Acid phosphatase, Peoxidase and Esterase isoenzyme activities were increased with increasing concentration of heavy metals. Electrical conductivity of tissue leachates of leaves of P. vulgaris L. was recorded minimum in control plants while maximum was recorded in 8g Pb and in 2.5g/kg Cd treatments. Activity of antioxidative enzymes as ascorbate peroxidase (APX; EC 1.11.11), guaiacol peroxidase (GPX; EC 1.11.1.7) and glutathione reductase (GR; EC 1.6.4.2) was increased while Catalase (CAT; EC 1.11.1.6) activity decreased with increasing concentration of heavy metals. [Nature and Science. 2009; 7(8): 63-75]. (ISSN: 1545-0740).