METABOLISM OF (2-C-14)-ABSCISIC ACID BY A CELL-FREE SYSTEM FROM EMBRYONIC AXES OF CICER-ARIETINUM L SEEDS

The metabolism of (2-C-14)-abscisic acid (ABA) in embryonic axes of chick-pea at 24 h of germination was studied by thin layer chromatography. A cell-free system of embryonic axes converted C-14-ABA to C-14-PA and the rate of conversion is enhanced 4-fold when the axes came from seeds germinated in 5x10(-4)M ABA. This ABA enhancement of its own metabolism has been observed in barley aleurone layers treated with ABA, but not in other plant tissues. In view of the recent observations that ABA is able to induce new proteins in germinating chick-pea seeds, it suggests that some of these ABA-induced proteins are involved in the conversion from ABA to PA in this tissue.