Distribution of Odontoglossum ringspot virus in apical meristems of infected Cymbidium cultivars.

Abstract The presence of Odontoglossum ringspot virus in the lateral and apical meristem domes of Cymbidium cultivars was revealed by electron microscopy. The analysis of transverse serial ultra-thin sections of apical meristems and of longitudinal serial ultra-thin sections of axillary bud meristems of donor plants, and of apical meristems of plantlets cultured from excised meristems, confirmed the presence of virus in the meristematic regions. These observations provide an explanation for the difficulties encountered in obtaining virus-free Cymbidium cv plantlets by meristem culture.