Elicitation of taxol biosynthetic pathway by ammonium citrate Operation Strategy Optimization of Glycyrrhiza uralensis Fisch Cell Amplification Culture in a Stirring Bioreactor Studies on the Acting Point of Arachidonic Acid in Taxol Bios ynthetic Pathway Separation and Identification of Triterpenic Acids from Suspended Cultured Cells of Cyclocarya paliurus RECENT ADVANCES IN THE PRODUCTION OF USEFUL CHEMICAL SUBSTANCES THROUGH PLANT CELL CULTURE