Cadmium Absorption and Transport Analysis of Rice Seedlings with Different Cd Accumulation Ability

In order to investigate the cadmium(Cd) uptake and transport characteristics of rice seedlings from two conventional indica rice varieties ‘ Huanghuazhan'(low Cd accumulation) and ‘ IR68144'(high Cd accumulation)with significant difference in grain Cd accumulation, the influence of concentration gradient of Cd stress on rice seedlings growth and the Cd accumulation features in root and shoot was studied, and the Cd enrichment dynamics of root and shoot over time was analyzed. The results indicated:( 1) Compared with ‘ IR68144',‘ Huanghuazhan' was more vulnerable to cadmium toxicity in high Cd concentrations, but cadmium promoting effect on its growth with low Cd concentrations was stronger too.( 2) In the concentration gradient Cd stress, the root Cd absorption ability of ‘ Huanghuazhan' was stronger than that of ‘ IR68144'. In low Cd concentration stress, the Cd content of ‘Huanghuazhan' shoot was also higher than that of ‘IR68144', but shoot Cd transfer coefficient of ‘ IR68144' was much higher than that of ‘ Huanghuazhan' at high Cd concentration, and as a result, its shoot Cd content was higher than that of ‘Huanghuazhan'.(3) Except the initial stage of Cd stress, the Cd content of ‘ Huanghuazhan' root was higher than that of ‘ IR68144'. Cd concentration in shoots of the two cultivars was similar at the early stage of Cd stress, but later, the Cd content of ‘ IR68144' was higher. The reason was that its shoot Cd transfer coefficient was increasing.