OCCURRENCE OF AROMATIC CYTOKININS IN OIL PALM (ELAEIS-GUINEENSIS JACQ)

The natural occurrence of 6-benzylaminopurine, 6-(2-hydroxybenzylamino )purine (ortho-topolin), 6-(3-hydroxybenzylamino)purine (meta-topolin) , their ribosides and 9-glucosides is reported using specific antibodi es to these groups of compounds in high performance Liquid chromatogra phy/enzyme-linked immunosorbent assay (HPLC/ELISA), Compounds were ide ntified by their retention times and differential cross-reactivities w ith six antisera in analyses carried out in two laboratories using dif ferent HPLC gradient systems, Identities were confirmed by immunoaffin ity purification followed by HPLC with on-line UV spectrum analysis. F urther confirmation of the occurrence of ortho-topolin riboside and is opentenyladenine-9-glucoside was obtained from gas chromatography-mass spectrometry analysis of permethylated HPLC fractions of an extract o f oil palm tissues. The aromatic cytokinins, and in particular, ortho- topolin riboside, were found in a variety of oil palm tissues at conce ntrations exceeding those of the isoprenoid cytokinins, zeatin, isopen tenyladenine, dihydrozeatin, and their ribosides, The 9-glucosides of isopentenyladenine and zeatin were more abundant than those of the aro matic types. The cross-reactivity of benzyladenine compounds with anti bodies to isopentenyladosine is discussed in relation to the interpret ation of ELISA data.