IMMUNOLOCALIZATION OF FERRITIN IN DETERMINATE AND INDETERMINATE LEGUME ROOT-NODULES

In eukaryotic organisms ferritin is a protein involved in the storage of iron. The occurrence of ferritin and its relationship to the effect iveness of the nitrogen-fixing activity have been previously studied d uring the early stages of the nodule development by biochemical method s. We have used immunocytochemistry techniques to determine the precis e location of ferritin and the behavior of this protein along the nodu le development. The major localization was found in plastids and amylo plasts of infected and uninfected cells of the three legume nodules st udied. A decrease of the immunolabelling was observed in infected cell s of lupin and soybean senescing nodules and in the senescent zone of indeterminate alfalfa nodules. In the cortex of soybean and lupin nodu les, ferritin increased during nodule ageing and the immunogold partic les were mainly located in crystalline structures. The putative role o f ferritin and plastids during nodule development is discussed.