Abstract
Bleeding sap of sunflower seedlings (Helianthus annuus) which had been transferred to 59Fe‐ or 54Mn‐labelled nutrient solution 16 hours before decapitation, was fractionated by gelfiltration on Sephadex G‐15.In both the 59Fe‐ and the 54Mn‐labelled bleeding sap three fractions could be determined, containing the microelement together with amino acids and carbohydrates.According to the results of gelfiltration, the molecular weight of these compounds ranges below 1500.