Tradescantia cytogenetic tests (root-tip mitosis, pollen mitosis, pollen mother-cell meiosis). A report of the U.S. Environmental Protection Agency Gene-Tox Program.

3 kinds of cytogenetic tests for screening of environmental mutagens were established for Tradescantia, namely, root-tip mitosis, pollen mitosis, and pollen mother-cell meiosis [commonly referred to as the Tradescantia-micronucleus (Trad-MCN) test]. All these tests are technically simple, inexpensive, and can yield reliable results in a relatively short time (36-72 h). The root-tip mitosis test is suitable only for liquid agents, while pollen mitosis is suitable for both liquid and gaseous agents. Pollen tube mitotic chromosomes are extremely sensitive to mutagens; therefore, they are good materials for detecting very low concentrations of mutagens. Both root-tip mitosis and pollen mitosis tests use chromosome and/or chromatid aberrations as end points for scoring. The Trad-MCN test is suitable for both liquid and gaseous agents. In addition, it is especially suitable for in situ monitoring of water and air pollutants. Of the 12 chemicals tested, 5-fluorouracil and 1,2-dibromoethane indicate that they are very potent mutagens based on the effective dosage used to produce a positive response. Sulfur dioxide, ethyl methanesulfonate, sodium azide, Phosdrin, and Bladex rank next in potency.