The Sequence of Appearance of Leghaemoglobin and Nitrogenase Components I and II in Root Nodules of Pisum sativum

Department of Molecular Biology, Agricultural University, De Dreijen 11, 6703 BC Wageningen, The Netherlands ABSTRACT The sequence of appearance of nitrogenase components I and II and leghaemoglobin in root nodules of pea plants inoculated with Rhizobium leguminosarum (strain PRE) was studied using radioimmunoassays. Leghaemoglobin was detected before nitrogenase activity. The MoFe component (I) of nitrogenase was detected at the same time as leghaemoglobin, while the Fe component (II) of nitrogenase and nitrogenase activity appeared 1 and 2d later, respectively. The same order of appearance of nitrogenase activity and leghaemoglobin was found in root nodules of cowpea plants inoculated with Rhizobium sp. 32H1.