Effects of lead, EDTA, and IAA on nutrient uptake by alfalfa plants

The element concentrations of alfalfa plants exposed for 10 d to 40 mg lead (Pb) L-1 from lead nitrate [Pb(NO3)(2)] alone, or combined with ethylenediaminetetraacetic acid (EDTA) and indole-3-acetic acid (lAA), was determined by inductively coupled plasma-optical emission spectroscopy (ICP-OES). Indole-3-acetic acid at 10 mu M and Pb/EDTA/IAA at 10 mu M increased potassium (K) concentration in roots by 87% and 94%, respectively (P < 0.05). However, lAA at 100 mu M decreased K concentration in leaves (P < 0.05). Plants exposed to 100 mu M IAA, Pb/IAA at 100 mu M, and Pb/EDTA/IAA at 100 mu M had, respectively, 30%, 55%, and 40% more sulfur (S) in leaves than control plants (P < 0.05). Lead and Pb/IAA reduced Ca concentration in stems and leaves (P < 0.05). Conversely, Pb and Pb/EDTA increased Cu. concentration in roots and stems. lAA at 100 mu M, Pb, and Pb/EDTA/IAA decreased Zn concentration in roots (P < 0.05). Manganese (Mn) and molybdenum (Mo) concentration in roots and stems was lower in plants treated with Pb and Pb/IAA (P < 0.05). Ph and Pb/lAA reduced (P < 0.05) the iron (Fe) concentration in roots. However, the addition of EDTA and IAA at 10 mu M reduced the negative effects of Ph on Fe absorption.