Abstract: Effects of water (control), citrate, malate and ethylenediaminetetraacetic acid (EDTA) on the uptake and translocation of cadmium (Cd) by rice seedlings were studied in nutrient solution. The results indicated that the addition of organic acids to solution affected the Cd uptake and translocation by rice seedlings. Compared with the control, EDTA significantly decreased the Cd uptake, with 90% and 96% reduction in the Cd concentrations of shoots and roots respectively. However, the addition of EDTA enhanced the Cd transport from roots to shoots, accounting for 43.0%-55.9% of total uptake (only 20.0%-32.2% for the control). Whereas, citrate and malate did not significantly affect the Cd uptake and transport by rice seedlings. The influence of organic acids on the Cd uptake and translocation by three rice cultivars showed a similar trend. EDTA had a higher ability to desorb Cd from rice root than citrate and malate.

Key words: forest litterfall, model, climatic factor, geostatistics, spatial pattern, remote sensing