[Characterization of cadmium uptake kinetics in cadmium pollution-safe rice material.]

The characteristics of cadmium (Cd) uptake kinetics in a pollution-safe rice variety of D62B were studied in a hydroponic experiment under different Cd levels and stress time, with a common variety Luhui17 as the control. The results showed that Cd uptake in root of D62B was significantly lower than that of Luhui17 under different stress times. The differences in Cd uptake of the two rice varieties increased with the extension of absorption time. Total Cd amount of Luhui17 was 1.3 times as much as that of D62B when the absorption time was 72 h. Meanwhile, the Cd uptake kinetic of the two varieties accorded to Michaelis-Menten equation, and little difference in Michaelis constants (K_m) was observed in the two varieties. However, the maximum uptake rate (V_max) of Luhui17 was 2 times as much as that of D62B. Once the stress time was more than 48 h, the transfer coefficients of D62B was lower than that of Luhui17, and the Cd distribution ratio in root of D62B was much higher, indicating that D62B had greater accumulation ability in root compared with Luhui17. In conclusion, the Cd uptake and transfer ability of D62B were lower than those of Luhui17.