Extraction of Auxin from Maize, from Smut Tumors of Maize, and from Ustilago zeae

The extraction of auxin by ether and by water from smut tumors of corn and other materials, frozen and vacuum dried, was studied. For a given weight of smut tumors, water extraction yields the greater amount of auxin. Dry ether extracts are not active. Water is necessary for the liberation of auxin from the tissues. Its action may be hydrolytic. 2. Smut tumors of corn yield auxin slowly with either water or ether extraction. The auxin is almost completely removed from the fungus, Ustilago zeae, in one ether extraction. 3. Smut tumors from corn leaves or stems yield more auxin than healthy leaves or stems. 4. Strains of U. zeae grown on a synthetic medium containing neither proteins nor amino acids are able to produce auxin. 5. Extracts of both types of medium upon which U. zeae had grown for 2 months contained much auxin and practically the same amount in each case. 6. The pathogenicity of strains of U. zeae seems to be correlated with their ability to produce auxin in a bacto-tryptone or a synthetic medium.