EDTA influences time and concentration dependent cadmium uptake characteristics of Indian mustard.

摘要

Hydroponic experiments were conducted to investigate the influence of EDTA on cadmium (Cd) uptake kinetics by Indian mustard (cv. 426308). The kinetics of Cd uptake in roots of 40-day-old B. juncea seedlings were studied. Seedlings were exposed to (A) 0.05-500 micro M Cd for 3 h, and (B) 0.05-500 micro M Cd-EDTA for 3 h, and subsequently washed in 1 mM Ca(NO3)2 for 15 minutes. The calculation using SigmaPlot shows that when B. juncea seedlings were exposed to A treatment, the saturable Ca2+ influx was characterized by a Km of 124 micro mol and a maximal influx (Vmax) of 24.9 micro mol g/dw per h. Application of equimolar EDTA to the Cd solution changed Cd uptake characteristics in roots significantly. The application of EDTA significantly decreased Cd accumulation by B. juncea as shown by both concentration- and time-dependent uptake experiments. Only free Cd2+ was available for plant uptake and only a small fraction of complexed Cd was splitted and could be taken up by the plant..