Virus particles in guttate and xylem of infected cucumber (Cucumis sativusL.)

Particles of plant viruses representing ten genera were visualised by elect ron microscopy in samples of guttate from systemically infected cucumber (C ucumis sativus L.) plants. For the majority of viruses tested, guttation sa mples tested positively by ELISA and infectivity was also demonstrated. Vir us particles of zucchini yellow mosaic potyvirus were also observed in xyle m in sections of infected root tissue. Since guttate originates from xylem exudate, this study demonstrates the potential for xylem tissue to act as a conduit for a diverse group of plant viruses in planta.