Uptake and apoplastic retention of EDTA- and phytosiderophore-chelated chromium(III) in maize

• Published in: Journal of plant nutrition and soil science 2007-12, Vol.170 (6), p.788-795
• Main Authors: Erenoglu, Bülent E, Patra, Hemanta K, Khodr, Hicham, Römheld, Volker, von Wirén, Nicolaus
• Format: Article
• Language: English
• Subjects: Agronomy. Soil science and plant productions; Biological and medical sciences; Cr(III) uptake; Fundamental and applied biological sciences. Psychology; General agronomy. Plant production; maize roots; phytoremediation; Soil and water pollution; Soil science; Soil-plant relationships. Soil fertility; Soil-plant relationships. Soil fertility. Fertilization. Amendments; synthetic chelate; Zea mays; ZmYS1
• ISSN: 1436-8730; 1522-2624
• DOI: 10.1002/jpln.200700068

Increasing the mobilization and root uptake of chromium (Cr) by synthetic and plant-borne chelators might be relevant for the design of phytoremediation strategies on Cr-contaminated sites. Short-term uptake studies in maize roots supplied with ⁵¹CrCl₃ or ⁵¹Cr(III)-EDTA led to higher apoplastic Cr contents in plant roots supplied with ⁵¹CrCl₃ and in Fe-sufficient plants relative to Fe-deficient plants, indicating that Fe stimulated co-precipitation of Cr. Concentration-dependent retention of Cr in a methanol:chloroform-treated cell-wall fraction was still saturable and in agreement with the predicted tendency of Cr(III) to precipitate as Cr(OH)₃. To investigate a possible stimulation of Cr(III) uptake by phytosiderophores, Fe-deficient maize roots were exposed for 6 d to Cr(III)-EDTA or Cr(III)-DMA (2'-deoxymugineic acid). Relative to plants without Cr supply, the supply of both chelated Cr species in a subtoxic concentration of 1 μM resulted in alleviation of Fe deficiency-induced chlorosis and higher Cr accumulation. Long-term Cr accumulation from Cr(III)-DMA was similar to that from Cr(III)-EDTA, and Cr uptake from both chelates was not altered in the maize mutant ys1, which is defective in metal-phytosiderophore uptake. We therefore conclude that phytosiderophores increase Cr solubility similar to synthetic chelators like EDTA, but do not additionally contribute to Cr(III) uptake from Cr-contaminated sites.