Abstract
The best conditions found for infection of tobacco mesophyll protoplasts with alfalfa mosaic virus (AMV) were pH 5.2, 2.5 µg/ml virus and 1 µg/ml poly-L-ornithine. Newly synthesized virus could be detected 15 h after inoculation and the virus concentration reached an estimated 106 to 107 particles per infected protoplast 2 days after inoculation.
* Present address: Institute for Plant Virus Research, 959 Aoba Cho, Chiba, Japan.