Micronucleus Assay with Tetrad Cells of Tradescantia

The Tradescantia micronucleus assay has been used for 50 years for the detection of genotoxins (including carcinogens) in the environment. Micronuclei are extranuclear bodies that contain entire chromosomes or chromosomal fragments and can be scored under the microscope. A large database concerning the effects of individual chemicals and complex environmental mixtures (soil, air, water) has accumulated. In contrast to other mutagenicity test systems, the effects of low concentrations of heavy metals, radionuclides, certain herbicides and pesticides, and gaseous mutagens can be detected, and it is also possible to conduct in situ biomonitoring studies with the plant. The test system has been validated, and standardized protocols have been developed for laboratory experiments and for field studies, which are described in this chapter.