Effects of trivalent chromium on biomass growth, water use efficiency and distribution of nutrient ele-ments in rice seedlings

Abstract

This paper presents an investigation of the effects of trivalent chromium on biomass growth (RGR), water use efficiency (WUE) and distribution of nutrient elements in young rice seedlings (Oryza sativa L. cv. XZX 45) exposed to chromium nitrate (Cr(III)) hydroponically. Results indicated that phytotoxicity of Cr(III) to rice seedlings was apparent, showing an linear decrease in both RGR and WUE with increasing Cr(III) concentrations. Using the Leven-berg-Marquardt Algorithm, the effective concentrations (EC) obtained from the RGR were always smaller than these from WUE, indicating that the former was more sensitive to change of Cr(III) application than the latter. Although a dose-dependent total accumulation rate of Cr in plant materials was observed, the translocation of Cr into shoots was a restricted process during phytotransport of Cr within plant materials. Results also showed that the effect of Cr(III) application on uptake and distribution of nutrient elements in rice seedlings was variable. In conclusion, the toxic response of young rice seedlings to Cr(III) was obvious and inhibitory effects were highly dependent on the total accumulation rate of Cr in plant materials.