The Metabolism of Zeatin by Cell-free Plant Extracts

Abstract

Summary Cell-free extracts prepared from senescing leaves of Ginkgo biloba and callus of Glycine max had the capacity to metabolise applied zeatin. The application of 8-[ 14 C]-zeatin to soybean callus extracts resulted in the recovery of four peaks that were active in the soybean callus bioassay. These peaks, yielding cytokinin activity, were also responsible for most of the radioactivity recorded. It would appear as if cell-free extracts are less efficient than intact cells in the conversion of zeatin to zeatin glucoside. The possibility nevertheless exists of using these techniques to obtain the enzymes that are responsible for the metabolism of zeatin in living cells.