Metal binding properties of high molecular weight soluble exudates from maize (Zea maysL.) roots

✍ Scribed by M. Mench; J.L. Morel; A. Guckert

• Publisher: Springer
• Year: 1987
• Tongue: English
• Weight: 448 KB
• Volume: 3
• Category: Article
• ISSN: 0178-2762
• DOI: 10.1007/bf00255778

✦ Synopsis

A high molecular weight (MW > 1000) soluble root exudate fraction (HS) was isolated from hydroponic axenic maize cultures in order to investigate its metal-binding properties. Measurements of the maximum binding ability (MBA) and the overall stability constants (log K) for cadmium-, copper-, lead-and zinc-HS associations were obtained from dialysis and ion-selective electrode titrations. All resuits showed the occurrence of organometallic bindings. Data fitted to linear Langmuir isotherms. The MBA, measured by dialysis titration, varied from 160 to 206 mEq/100 g HS according to the nature of the metal, log K values, following the series Pb ~> Cu > Cd 5 Zn, varied from 3.15 to 3.65. Due to these metalbinding properties, soluble root products could play a role in the transfer of metal into the rhizosphere.