Abstract: Plant protoplasts are exposed for interaction with an external agent by exposing the plasma membrane of protoplasts in the root hairs of the plant without release of protoplasts from the plant. This may be achieved by enzymatically degrading the plant cell wall at the apices of root hairs under conditions which expose the plasma membrane whilst maintaining or readily permitting restoration of the essential functional integrity of the plant. Enzymatic degradation of the cell wall of the apices of root hairs is possible in a wide range of crop species and other species and to expose the plasma membrane with partial protoplast release. This enables direct interaction with plasmids, viruses and micro-organisms at the surface of the plasma membrane of their exposed protoplasts, or the fusion of these with isolated protoplasts of other plant systems.

Abstract: Somatic hybrid plants of the genus Lycopersicon are produced by fusion of protoplasts of two species, one of which cannot be regenerated from protoplasts. This procedure enables the introduction of certain desirable traits of wild-type members of the genus into cultivated tomato species which do not regenerate from protoplasts.