Translocatable Plant Growth Inhibitors Produced by Penicillium Thomii and Arachniotus trisporus.

Abstract

P. thomii and A. trisporus were found to produce translocatable plant growth inhibitors when cultured on corn steep-cerelose medium. When one of the primary leaves of bean plants was treated with the culture filtrates of these organisms the compound leaves which develop later were not symmetrical but were inhibited more or less selectively on the side of the treated leaf. Stem elongation of bean plants and the growth of corn plants were also inhibited by treatment with these culture filtrates. The inhibitors are heat stable at pH 5, 7, and 9 but are destroyed by autoclaving at pH 2, are dialyzable, and are not adsorbed on charcoal. They are soluble in methanol and ethanol but insoluble in benzene, chloroform, ethyl acetate and ethyl ether. The inhibitors could be adsorbed by the anion exchange resins IRA-400 and Dowex 1-X8 and eluted from the columns with 0.75% NaCl.