CYTOKININS IN EXUDATES FROM LEAVES AND ROOTS OF RED PERILLA

Leaf and root exudates from the red variety of the short-day plant Perilla frutescens were analysed for cytokinin content using combined HPLC-RIA. Three radioimmunoassays, for zeatin-type, dihydrozeatin-type and iso-pentenyladenine-type cytokinins were employed. Activities corresponding to iso-pentenyladenosine, iso-pentenyladenine 9-glucoside, zeatin riboside, zeatin 9-glucoside, zeatin ribotide and zeatin were detected in leaf exudates. The principal activity in root exudates corresponded to zeatin riboside though a much lower level of activity corresponding to iso-pentenyladenosine was also sometimes detected. Greater amounts of iso-pentenyladenosine and zeatin riboside apparently exuded from leaves which had been exposed to short days than from those which had been kept in long days or night-interrupted short days.