Metabolism of 2,4-dichlorophenoxyacetic acid. II. Metabolism of the side chain by bean plants

The Fate of 2,4-Dichlorophenoxyacetic Acid in Bean Seedlings. I. Recovery of 2,4-Dichlorophenoxyacetic Acid and Its Breakdown in the Plant

“…Splitting off of the side chain will in general lead to its oxidation. This probably accounts for the results of Weintraub and others which demonstrate that when 2,4-D with C14 in the side chain is given to plants, the C14 comes off in CO2 (7,15,26) or is converted into numerous compounds other than 2,4-D (14,15,16,28 THE AUXIN ASSAY: The slit-pea test is the most convenient assay for the 2,4-D extracted from treated plants, both becauise it is relatively quick and simple, and because it is highly sensitive to 2,4-D and much less so to indole-acetic acid (IAA). As noted above, the relative activity of 2,4-D is from 8 to 12 times that of IAA in this test (22).…”

Relation of Phosphorus Nutrition to the Translocation of 2,4-Dichlorophenoxyacetic Acid in Tomato Plants

“…Such movement appears to have been greater in the group which received the phosphorus 8 hours before application of the 2,4-D than in either of the groups which received the phosphorus later but less than in the group which received the phosphorus 3 days before. There is considerable evidence that 2,4-D is metabolized in the plant (4,5,15), and it cannot be said that the movement of the radioactive material in these cases is definite proof of the movement of 2,4-D. Since the (lata from the autoradiograms seem to agree with the evidence based on such growth responses as stem curvature and inhibition of terminal growth, we believe it likelv that at least some of the C14 has remained attached to a biologically active form of the growth regulator, at least for the 24-hour period tested in these experiments.…”

Metabolism of 2,4-Dichlorophenoxyacetic Acid. III. Metabolism and Persistence in Dormant Plant Tissue.

“…Although a portion of the applied growth-regulator is rapidly transformed into a variety of products (5,15,16), a significant amount may remain unaltered for at least 42 days (6). Less direct evidence of persistence of an active growth-regulator has been provided also by observations of protracted morphological responses in cotton (4,7,8) and of long delayed fruit abscission in apple (10).…”