水稻镉安全材料的镉吸收动力学特征

Characterization of cadmium uptake kinetics in cadmium pollution-safe rice material

采用水培试验,以前期筛选出的水稻Cd安全材料D62B为试验材料,普通材料泸恢17为对照材料,在不同Cd浓度和时间处理下,研究水稻Cd安全材料的Cd吸收动力学特性.结果表明:在不同Cd处理时间下,D62B根系对Cd的吸收总量均低于泸恢17,且随吸收时间的延长,差异逐渐增大.当吸收时间达到72 h,泸恢17体内积累的Cd总量为D62B的1.3倍.两种水稻材料Cd吸收动力学符合米氏方程,米氏方程常数(K_m)值差异不大,但泸恢17的最大吸收速率(V_(max))是D62B的2倍.当Cd处理时间大于48 h,D62B根系对Cd的转移系数低于泸恢17,且其根部Cd分配比例明显大于泸恢17,即D62B根系对Cd的固持能力大于泸恢17.D62B的Cd吸收能力较弱,且其向地上部转移Cd的能力显著低于泸恢17.

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 （Km） was observed in the two varieties. However, the maximum uptake rate （Vmax） 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.