Effects of Glyphosate on Caffeic Acid Metabolism in Perilla Cell Suspension Cultures

Perilla cell suspension cultures contained caffeic acid at 0.073%of the fresh weight. When 1 min glyphosate was administeredto the cell culture in the logarithmic and stationary phases,the amount of caffeic acid ceased to increase and remained ata nearly constant level during the following several days. Phenylalanineammonia-lyase (PAL) activity in the cell culture increased immediatelyafter transfer to a fresh medium, decreased rapidly in the midstof the logarithmic phase and became almost undetectable in thestationary phase. PAL activity was markedly inhibited by glyphosateat more than 0.2 mM. The shikimic acid content of cells from14-day culture grown in the presence of 1 mM glyphosate increasedup to 74.9 µg per g fresh weight during 6-day culture,whereas that of the control cells was undetectable. The dosageof 0.15 mM L-2-aminooxy-3-phenylpropionic acid (L-AOPP), aninhibitor of PAL, to the cells did not cause shikimic acid accumulation. (Received June 25, 1983; Accepted October 6, 1983)