Metabolism of gibberellins A(1) and A(3) in fruits and shoots of Prunus avium?

Isotope-labelled GA metabolites were identified by GC-MS. following HPLC fr actionation of extracts derived from fruits or shoots, that had been incuba ted with [H-2]- and [H-3]- GA(1) or [H-2]- and [H-3]- GA(3) GA(1) (1)was co nverted into GA(8) (10) by developing fruits and vegetative shoots of sweet cherry (Prunus avium cv. 'Stella'), while GA(3) (4) was converted into GA( 3)-isolactone (17). Other metabolites of each GA were detected but were not identified unequivocally. These included a metabolite of GA(1) (1) in frui tlets that was mure polar (by reverse phase HPLC) than GA(x) (10) and a met abolite of similar polarity to GA(87) (6). was obtained after incubating fr uitlets with GA (4). However, no evidence was obtained to suggest that GA(8 7) (6) was a metabolite of GA(3) (4) or that GA(85) (2) was a metabolite of GA(1) (1) in these tissues, under the conditions used. The pattern of meta bolites obtained from vegetative tissues was similar to that from fruitlets . However. the results suggested that GA(1) (1) and GA(3) (4) were metaboli sed at a greater rate in shoots from mature trees than in shoots from seedl ings, and that GA(1) (I)was metabolised more rapidly than GA(3) (4) in juve nile and mature shoots. We conclude from these observations that GA(3). (4) is not a precursor of GA(87) (6) and GA(32) (5), also, that GA(1) (I) is n ot a precursor of GA(85) (2) and GA(86), (3) in developing fruits or in veg etative: shoots of sweet cherry. 2001 Elsevier Science Ltd. All rights rese rved.