[01] Miao Ding, School of Environmental & Safety Engineering, Changzhou University, Changzhou, China. [02] Yuankang Liu, School of Environmental & Safety Engineering, Changzhou University, Changzhou, China. [03] Jianguo Liu, School of Environmental & Safety Engineering, Changzhou University, Changzhou, China.

In order to understand some mechanisms on the variations among rice cultivars in plant Pb accumulations, the relationships between root oxidation characteristics and Pb uptake and translocation were studied with six rice cultivars at different soil Pb levels. The results showed that the variation rates among the rice cultivars were 27.2%–49.6% in root Pb concentrations, 69.7%–122.1% in shoot Pb concentrations, 14.3%–41.0% in root radial oxygen loss (ROL) per root weight, 172.4%–240.6% in total ROL per pot, and 35.9%–47.2% in soil redox potentials (Eh). The magnitudes of the variations for the parameters followed a same trend: 1000 mg kg^-1 soil Pb treatment > 500 mg kg^-1 soil Pb treatment > the control. Root ROL (per root weight and per pot) correlated positively and significantly (P < 0.05 or 0.01) with root Pb concentrations, but insignificantly (P > 0.05) with shoot Pb concentrations. Soil Eh correlated positively and highly significantly (P < 0.01) with Pb concentrations of roots and shoots. Soil Eh correlated positively and partially significantly (P < 0.05 or 0.01) with root ROL. It can be concluded that root ROL influences Pb uptake by rice root highly, but Pb translocation from root to shoot is little related to root ROL. Pb uptake and translocation to aerial parts are highly and directly affected by soil redox status. By affecting soil Eh, root ROL may indirectly influence Pb uptake and translocation in rice plants.

Lead (Pb), Rice (Oryza sativa L.), Cultivar, Root Oxidation, Soil Redox Potential

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