Effect of cadmium on iron uptake in cucumber roots: A Mössbauer-spectroscopic study

Abstract

The uptake and accumulation of iron in cucumber roots exposed to cadmium were investigated with Fe sufficient and deficient cucumber plants using Mössbauer spectroscopy, Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and ferric chelate reductase activity measurements. Both Fe sufficient and Fe deficient plants were applied. In the case of Fe sufficient cucumber roots grown in nutrient solution with 10 μM Cd no changes were found in the occurrence of Fe species (mostly hydrous ferric oxides and ferric-carboxylate complexes) compared to the control where no Cd was added. In the Fe deficient roots pretreated with 0, 0.1, 1, 10 and 100 μM Cd for 3 h then supplied also with 0.5 mM 57 Fe-citrate for 30 min, Fe II was identified in a hexaaqua complex form. The relative amount of Fe II was decreasing simultaneously with increasing Cd concentration, while the relative occurrence of Fe III species and total Fe concentration were increasing. The results support the inhibitory effect of Cd on Fe-chelate reduction. Although the reductase activity at 10 and 100 μM Cd treatment was lower than in the iron sufficient control plants, Fe II could be identified by Mössbauer spectroscopy whereas in the Fe sufficient control, this form was below detection limit. These data demonstrate that the influx and the reoxidation of Fe II was decreased by Cd, consequently, they refer to the competition of Cd 2+ and Fe 2+ during the membrane transport and the inhibition of the reoxidation process. Keywords Cadmium . Iron . Fe-citrate . Mössbauer spectroscopy . Strategy I . Fe reductase activity Abbreviations FRO ferric reductase oxidase IRT1 iron-regulated transporter 1 NRAMP natural resistance-associated macrophage protein Plant Soil (

Cadmium Effects on Mineral Accumulation and Selected Physiological and Biochemical Characters of Salix babylonica L.

“…Adding Mn to the solution containing Cd can significantly improve plant growth and reduced the concentrations of Cd in all organs of the plant [47]. Evidence from Kovács et al's work [48] demonstrated that Fe ions might compete with Cd ions for the same membrane binding (transport) sites in plants.…”

Salix matsudana Koidz Tolerance Mechanisms to Cadmium: Uptake and Accumulation, Subcellular Distribution, and Chemical Forms

“…The Fe level in roots of S. matsudana showed significant decrease under Cd stress. Kovács et al [56] indicated that Fe ions may compete with Cd ions for the same membrane binding (transport) sites in plants, and so an adequate Fe ion supply may decrease Cd uptake and relieve Cd toxicity in plants. Studies have provided clear evidence that Fe can alleviate to some extent the Cd-induced inhibitory effects on plant growth [1].…”

Accumulation and distribution of iron, cadmium, lead and nickel in cucumber plants grown in hydroponics containing two different chelated iron supplies

“…IRT1 in Zn, Mn, Co and Cd transport (Conolly et al, 2002;Vert et al, 2002) and NRAMP3 in Cd and Mn transport (Thomine et al, 2003). The Strategy I mechanism of iron uptake and its interaction with Cd have recently been shown by Mössbauer spectroscopic studies in cucumber (Kovacs et al, 2009(Kovacs et al, , 2010.…”