Determination of potencial N2-fixing activity of bacteria in sugarcane roots and bean nodules using triated acetylene reduction technique and electron microautoradiography - Silva, Darcy Martins da; Ruschel, Alaides Puppin; Matsui, Eiichi; Nogueira, Neusa de Lima; Vose, Peter B (Associative N2-fixation, 1981)