Aufnahme und Sorption von zwei- und dreiwertigem Eisen durch Sonnenblumenpflanzen (Heliantus annuus L.)

Uptake and adsorption of ferrous and ferric iron by sunflower plants The uptake of iron by 13 day-old sunflower seedlings in water culture experiments was studied using FeCl₃, Fe-citrate and ferroammoniumsulfat (Mohr'sches Salz) in the-nutrient solution. By raising the N-, K- and Ca-content and lowering the P-content of the nutrient solution at the same time the iron content of the exudate in the FeCl₃-treatment was increased up to 200 %. In the case of Fe-citrate, similar values were obtained only under aeration conditions of the nutrient medium. Application of iron as ferrous sulfate led to an increase of the iron content in the exudate and in the aerial plant parts amounting to about 200 and 400 %. respectively over that of the FeCl₃ treatment. After 15 hr-uptake, most of the iron, taken up by the seedlings was in an unexchangeable form in the root system. The results give a further evidence for the peferential uptake of iron in the ferrous form.