Estudo ao microscópio electrônico de tecidos de plantas infetadas pelo vírus do mosaico comum e mosaico amarelo do feijoeiro Electron microscopy of common and yellow bean mosaic viruses in infected tissues

Exames ao microscópio electrônico de tecidos foliares e radiculares de plantas infetadas pelo vírus do mosaico comum ou do mosaico amarelo do feijoeiro, mostraram a presença de dois tipos de inclusões no cito-plasma: filamentosas, consideradas como partículas de vírus, e lamelares, típicas dos vírus do grupo Y. Essas inclusões não foram encontradas no pólen ou no óvulo de feijoeiros infetados. Como o vírus do mosaico comum do feijoeiro é transmitido pelo pólen, sugere-se que êle ocorre nestas células em concentração muito baixa, ou mesmo na forma de ácido nucléico.<br>Two types of cytoplasmic inclusions were observed in leaf and root tissues of host plants infected with the common and yellow bean mosaic viruses: (1) filamentous inclusions considered as an aggregate of virus particles and (2) lamellar inclusions which appeared with varied configurations that represent sections at different angles of the same cylindrical structure. No type of inclusion or virus particle was seen in pollen and ovule from bean plants infected with each of the two viruses. Since, however, the common bean mosaic virus is transmitted through the pollen it is suggested that it occurs in very low concentration in this structure or else as viral nucleic acid