CADMIUM UPTAKE BY PISUM-SATIVUM - ACCUMULATION AND DEFENSE-MECHANISM

Roots, stem and leaves of Pisum sativum (cv. Caravella) grown in Hoagland's solution supplemented with 1, 2.5 and 5 mM Cd(NO3)2 were analyzed for Cd total content, Cd extractable by K-Phosphate buffer and separation of Cd induced protein fractions. The Cd distribution in tissues showed that roots contained the higher amounts of total Cd, whereas small fraction of absorbed Cd was translocated and accumulated in leaves. Conversely to stem and leaves, root extracts contained the lowest percentage of extractable Cd. Gel-filtration of tissue extracts showed that part of Cd eluted as the free metal ion, the remaining part of Cd total content being associated with molecular fraction with low app. M.W. (5.3 KD). A second protein fraction with app. M.W. > 30 KD was present in roots extract only. The synthesis of induced proteins in tissues of plants treated with increasing Cd concentration was quantitative.