IRON-OXIDE DEPOSITION ON AXENIC AND NON-AXENIC ROOTS OF RICE SEEDLINGS (ORYZA-SATIVA L)

Wetland plant roots are often coated with iron oxides. The aim of this study was to determine if micro-organisms growing in the rhizoplane affect the amount of iron oxide deposition. Methods were developed to compare axenic and non-axenic rice plants grown in environmental chambers and exposed to solutions of ferrous iron. Axenic roots accumulated significantly (p < 0.05) more iron oxides than did non-axenic roots. The pH of iron solutions after exposure to axenic and non-axenic seedlings was significantly different. Roots exposed to micro-organisms from two different soils did not significantly differ in iron oxide deposition or pH of iron solutions. It is therefore hypothesized that although the results show that micro-organisms have the potential to decrease the amount of iron oxide deposition, this decrease may not result in site-to-site differences in iron oxide deposition on wetland plant roots.