The metabolism of possible cytokinin precursors supplied to excised maize roots

Abstract

Excised maize roots were grown, in vitro, On nutrient media supplied with labelled mevalonic acid, isopentenylpyrophosphate or glycine. After 35 days incubation the roots were separated from the agar medium. Both the roots and the respective culture media were extracted for cytokininlike activity. Biological activity was detected in both roots and media in all cases. Approximately all radioactivity detected was associated with the applied compound in the case of mevalonic acid and isopentenylpyrophosphate. Where roots were supplied with labelled glycine small amounts of labelled adenine and adenosine were detected in the root extracts. In no case was radioactivity found to be associated with free cytokinins.S. Afr. J. Bot. 1985, 51: 417–420 Geisoleerde mieliewortels is in vitro op voedingsmedia wat radioaktiewe mevalonsuur, isopentenielpirofosfaat of glisien bevat het, gekweek. Na 35 dae is die wortels van die media geskei. Beide die wortels en die verskillende media is vir sitokinien-aktiwiteit getoets. Biologiese aktiwiteit is in alle gevalle in die wortels en media gevind. In die geval waar mevalonsuur en isopentenielpirofosfaat aangewend is, was die meeste van die waargenome radioaktiwiteit met hierdie twee verbindings geassosieer. Waar die wortels van glisien voorsien is, is klein hoeveelhede gemerkte adenien en adenosien in die wortelekstrakte gevind. In geen geval is radioaktiwiteit geassosieer met vry sitokiniene gevind nie. S.-Afr. Tydskr. Plantk. 1985, 51: 417–420