INFLUENCE OF CADMIUM AND LEAD ON PHYSIOLOGICAL AND BIOCHEMICAL RESPONSES OF SESAMUM MDICUM (L) SEEDLINGS. II. CELL INJURY, PIGMENT, SUGAR, NUCLEIC ACID CONTENT AND PEROXIDASE ACTIVITY

摘要

Physiological and biochemical responses of Sesamum Indicum (L) seedlings under the influence of Cadmium and Lead were investigated with reference to the cell injury, photosynthesis pigment contents, variation in soluble and insoluble sugar contents, changes in nucleic acid contents and peroxidase activity. With the increasing concentration of both the metals cellular damage was proment. Pigments like chlorophyll a and b and Carotenoids also decreased. The total soluble sugar increased with the increasing concentration of heavy metals but the insoluble sugar decreased. In case of both Cd and Pb treatment the activity of peroxidase clearly decreased in root, stem and leaf. RNA increased remarkably after 24h of treatment and later started decreasing, but a decreasing trend in DNA content was recorded from the beginning of the treatment. Cadmium was more toxic than Lead and the root was the most sensitive part when compared with stem and leaf.