有机酸对苗期水稻吸收和运输镉的影响

Effects of organic acids on the uptake and translocation of cadmium by rice seedlings

采用营养液培养法，研究了水（对照）、柠檬酸、苹果酸和乙二胺四乙酸（EDTA）4个处理对不同品种水稻幼苗吸收和转运cd的影响及其对根中cd的解析作用。结果表明：与对照相比，EDTA的添加明显抑制了水稻根部对cd的吸收，使水稻幼苗地上部和根中Cd的含量分别降低了90％和96％；但促进了Cd向地上部的运输，地上部Cd量占总吸收量的43．0％-55．9％（对照组为20．0％～32．2％）。而柠檬酸和苹果酸的添加对水稻根系吸收和运输Cd的影响较弱。3种有机酸对不同水稻品种Cd吸收的影响趋势一致。解析试验的结果表明，EDTA对根中的Cd具有较强的解吸能力，而柠檬酸和苹果酸相对较弱。

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.