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Metabolism of ricinine in the castor plant.

1965; Oxford University Press; Volume: 40; Issue: 5 Linguagem: Inglês

10.1104/pp.40.5.803

1532-2548

George R. Waller, Mengyue Tang, Mike Scott, F J Goldberg, Jary S. Mayes, H. Auda,

Transgenic Plants and Applications

Dturing the early period of the twentieth century, it was generally thought that alkaloids were by- p)roducts of a number of irreversible and physiologi- cally useless reactions associated with nitrogen me- tabolism (1-3).This idea was gradually discarded as an increasing number of experiments showed that alkaloids are metabolically active.Indirect evidence for the decomposition of ricinine (II, fig 1) in the living plant was obtained by several investigators in nonisotopic experiments.Weevers (4) showed that the ricinine content de- creased with increasing age of castor plants grown on nitrogen-depleted soil.Bogdashevskaya (5) showed that the content of ricinine was reduced in leaves which were shaded from the light, while the upper unshaded leaves of such1 plants prodtuced super- normal levels of ricinine.Waller and Nakazawa ( 6) reporte(d that ricinine wsas rapidly utilize(I by castor cotvledlons in the (lark; however, the amount of ricinine did not clecrease when nicotinic acid was l)resent in the medium.A preliminary report (7) has been made on the degradation of ricinine in a cell-free system of young castor plants.Tso and Jeffrey (8) were the first to use iso- topic tracers to demonstrate that alkaloids are me- tabolically active.They fed nitrogen-15 labeled ni- cotine (III, fig 1), nornicotine and anabasine (IV, fig 1) to tobacco plants and found that a major 1Received February 9, 1965.