A rapid, simple, and cost-effective testing procedure is described for determining the potential of a chemical to affect germination and early growth of terrestrial plants. Radish (Raphanus sativus L. var. Champion 708), lettuce (Lactuca sativa L. var. 525 Ithaca M.T.O.), and perennial ryegrass (Lolium perenne L. var. Manhattan) are routinely used in this test because of their economic and ecological importance, quick and high rate of germination, and relatively uniform root and hypocotyl/coleoptile growth. Plants are exposed to the chemical for seven days, after which germination, root length, and plant height values are determined. Average values for treated plants are compared with the corresponding values for the control (untreated) plants. An observed ratio (treated versus control means) of <90% is considered to be a significant indication of adverse chemical effect.
Test results for 26 commercial chemicals are compared with information in the literature. For these commercial chemicals, reduction in root length was the most sensitive plant response, followed by reduction in the plant height. By comparison, germination was not noticeably affected. Ryegrass and radish were found to be equally tolerant species, and lettuce was the most sensitive plant species. Where data for other plant-effect methods are available, comparisons show that this method is generally of equal or greater sensitivity in identifying the potential for chemical effects.