CADMIUM ABSORPTION BY RICE PLANTS .1. MODE OF THE ABSORPTION

Cadmium absorption by rice plants was examined by means of water culture experiments with l15mCd. The time course of the cadmium absorption by young plants was found to consist of two phases: one was the initial rapid phase and the other was the succeeding rather steady phase with smaller absorption rate. Cadmium distribution within rice plants were related to the phases of absorption. About 60% of 115mCd absorbed in the initial phase was released (exchanged) when soaked in 10 ppm cadmium solution. Incorporation of cadmium occurred in killed roots also. Rice plants absorbed cadmium actively when cadmium concentration in culture solution was low, while when it was high the mode of absorption implied that rice roots might actively depress the income of cadmium. Relationship between the rate of cadmium absorption by excised roots and the cadmium concentration in culture solution showed a kind of dual pattern. © 1979 Taylor & Francis Group, LLC.