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The Extraction of Auxin from Plant Tissues
Kenneth V. Thimann and Folke Skoog
American Journal of Botany
Vol. 27, No. 10 (Dec., 1940), pp. 951-960
Published by: Botanical Society of America, Inc.
Stable URL: http://www.jstor.org/stable/2436565
Page Count: 10
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The extraction of auxin by solvents from a number of plant materials has been studied. In Lemna, grown under controlled conditions, repeatable results can be obtained by successive extractions with ether, but the process requires several months to reach completion. Chloroform, ethyl alcohol and water are less satisfactory solvents. If chloroform is used, the material must be acidified, and there is danger of inactivation. The process cannot be hastened by steaming, boiling at different pH, extraction in the Soxhlet apparatus, or grinding. All these treatments reduce the total yield. With Avena coleoptiles the auxin is almost completely extracted in 24 hours, but the roots, and to a lesser degree the leaves, behave like Lemna. Phaseolus root-nodules and cultured Nicotiana callus show still other types of behavior. Water is essential for the extraction process in all these materials. On drying, the auxin, whether previously bound or free, becomes "fixed" in a non-extractable form. This "fixation" may or may not be accompanied by a partial destruction. Water is also necessary for the hydrolytic liberation of auxin from its bound form in the tissues. This process determines the rate at which auxin can be extracted.
American Journal of Botany © 1940 Botanical Society of America, Inc.