Synergism of polygodial and trans-cinnamic acid on inhibition of root elongation in lettuce seedling growth bioassays.
A bicyclic sesquiterpene dialdehyde, polygodial did not inhibit root elongation up to a concentration of 12.5 microg/ml in a lettuce seedling assay: trans-Cinnamic acid inhibited the elongation by 50% at 1.2 microg/ml (8.1 microM). The inhibitory activity of trans-cinnamic acid was enhanced 17-fold when used in combination with 6.25 microg/ml (26.5 microM) of polygodial. A decrease in the pH of the medium was observed during normal seedling growth, indicating transport of protons from the cells by a plasma membrane H+-ATPase. The inhibitory effect of trans-cinnamic acid on the elongation was reduced to some extent in 2 mM phosphate buffer (pH 7.0) during seedling growth. Although polygodial did not inhibit the activity of H+-ATPase in the plasma membrane fraction of roots in normally growing seedlings, a decrease in activity was found in the fraction obtained from seedlings incubated with 20 microg/ml of polygodial. These results suggest that polygodial functions synergistically with trans-cinnamic acid in the inhibition of root elongation via restriction of proton transport from the cytoplasm of germinated cells.
Fujita
Ken-Ichi
K
Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan. kfujita@sci.osaka-cu.ac.jp
Kubo
Isao
I
D001681:Biological Assay; D002934:Cinnamates / Q000737:chemistry / Q000494:pharmacology*; D003593:Cytoplasm; D004347:Drug Interactions; D018525:Germination; D006863:Hydrogen-Ion Concentration; D018545:Lactuca / Q000254:growth & development*; D018517:Plant Roots / Q000254:growth & development*; D036226:Seedlings; D012717:Sesquiterpenes / Q000737:chemistry / Q000494:pharmacology*; D013237:Stereoisomerism
D002934:Cinnamates; D012717:Sesquiterpenes; C029010:cinnamic acid; C034380:polygodial