ISOLATION FROM SUGAR BEET FRUIT AND CHARACTERIZATION OF CIS-4-CYCLOHEXENE-1,2-DICARBOXIMIDE AS A GERMINATION INHIBITOR

The isolation of cis-4-cycIohexene-1,2-dicarboximide as a germination inhibitor from the fruit of sugar beet seeds has been followed by its inhibition of lettuce seed germination. A similar compound was present in wheat chaff or dormant wheat seed. The isolation procedure involved ether extraction, silicic acid chromatography, cellulose chromatography, Sephadex G-10, and crystallization. Identity was confirmed by synthesis and comparison of physical and biological properties. Derivatives were synthesized, and the most active structure was the N-butyl analog which inhibited lettuce seed germination at 10-5 M. Inhibition of germination was measured by failure of the embryo to grow, by the absence of increased respiration, and by low rates of leucine-14C incorporation into protein. Germination inhibition by the compounds was not reversed by gibberellin, indole acetic acid, or light treatments. Seeds inhibited by the compounds would germinate when washed with water to remove the inhibitors. cis-4-Cyclohexene-1,2-dicarboximide is a naturally occurring biological compound which is structurally comparable to other dicarboximide inhibitors such as cycloheximide, Captan, and maleimides. © 1968, American Chemical Society. All rights reserved.