Role of fulvic acids for transporting and fixing phosphate and iron ions in bean plants by radiotracer technique

Among humic substances formed by organic matter decomposition process, fulvic acids have been extensively studied because their solubility and soil fertilizer properties. This paper describes how some mineral nutrient elements are absorbed by the root as well as the foliage of bean plants and how they move in both directions depending on their association to fulvic acids. In this study, radiotracers of phosphate and iron have been used (H₂ ³²PO₄ ^-, ⁵⁹Fe²⁺). The results obtained are quantitative by instrumental detection and qualitative by autoradiography of the radiotracers. A very clear effect has been found about motion and fixation of phosphate and iron ions in bean plants brought about by fulvic acids commercially produced in Mexico by organic synthesis. This effect seems to be the more homogeneous distribution in the vegetable tissues of the mineral ions absorbed from the soil. This revised version was published online in August 2006 with corrections to the Cover Date.