Uptake and transport of Cd supplied at early growth stage in hydroponically cultured soybean plants

Soybean plants (Glycine max) were grown in hydroponic culture solution and applied Cd via roots for 48 h at early growth stage (third and fourth node; V3-4). Soybean plants were sampled at the growth stages as follows: full bloom (R2), full pod (R4), full seed (R6), beginning maturity (R7), and full maturity (R8). The concentration and amount of Cd in each part were determined. Cadmium absorbed by the soybean at V3-4 was transferred into stems, petioles and leaves until R2 growth stage, and the Cd remained until R4 stage in each part. After R4 stage, Cd amount in leaves decreased steeply. On the other hand, Cd amount in pods and seeds increased from R6 to R7. These results indicate that Cd accumulated in leaves was translocated to seeds at R7 stage.