A Review of the Place of in vitro Cell Culture Systems in Studies of Action, Metabolism and Resistance of Biocides Affecting Photosynthesis

The homogeneity, density and axenic nature of cell culture systems have made them an ame­ nable tool for studying many aspects of biocide research; screening, metabolism, mode of action and resistance. Cell cultures are “multi-homogeneous” and each homogeneous state may be analog­ ous to different plant parts. Cultures can be homogeneously green, homogeneously white in either a homogeneously exponential or stationary phase of growth. Examples are be presented showing why no single homogeneous state should be envisaged to be analogous to a whole plant in biocide studies. Because of the possibility of more uniform herbicide application, culture systems have a use in isolating resistant crop strains, at higher selection pressures and much higher “plant” densities than is possible in the field, with recent successes. Protoplast fusion techniques may allow the transfer of genetic resistance between related but genetically incom patible crop species.