Abstract
A method for the extraction and bioassay of 2,4-D from treated plants is described. The 2,4-D was applied to the primary leaf of bean seedlings (Phaseolus vulgar is var. Dwarf Red Kidney). It was then extracted from various parts of the bean seedlings and the extracts partially purified. The bio-assay used was the slit pea curvature test which is particularly responsive to 2,4-D. Recovery from bean seedlings is quantitative, but freely extractable 2,4-D rapidly disappears in the plant. This loss, presumably breakdown, is considerably faster in light than in darkness but even in the dark three-quarters of the absorbed 2,4-D disappears in 5 days. The advantages of the method over those based on indirect criteria are discussed.