Alicyclic acid metabolism in plants 4. Effect of external supplies of shikimate and quinate to excised hypocotyls ofPhaseolus mungoseedlings

摘要

When excised hypocotyls of etiolatedPhaseolus mungoseedlings were allowed to take up shikimate solutions of various concentrations for 4 to 32 hr at 25°C in the dark, a marked rise in endogenous quinic acid level appeared in the organ. A similar effect was observed, to a lesser extent, in other organs, i.e. roots and cotyledons. When quinate solution was supplied to hypocotyls, the effect on the increase of endogenous shikimic acid concentration was discernible, although it was not as remarkable as the profound effect of shikimate on quinic acid level. A supply of either of the acids to excised hypocotyls in a culture solution resulted in a significant increase in dehydroquinate dehydratase activity in the organ, whereas shikimate dehydrogenase activity was slightly, if at all, affected by this treatment. On the basis of these experimental results, the metabolic role of quinic acid in aromatic biosynthesis in this plant is discussed