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Chlorophyll and porphyrin synthesis in relation to iron in Nicotiana tabacum, L.

1965; Elsevier BV; Volume: 111; Issue: 2 Linguagem: Inglês

10.1016/0304-4165(65)90049-8

1872-8006

W. P. Hsu, Gene W. Miller,

Cassava research and cyanide

1. The effect of iron on chlorophyll and porphyrin synthesis was investigated. The rates of incorporation into chlorophyll of 14C-labeled substrates were compared in leaf discs from normal and chlorotic Nicotiana tabacum. Leaf discs from normal or chlorotic plants incorporated [14C]succinate or δ-amino[14C]levulinic acid at increased rates when iron was added to the incubation mixture. Incorporation into chlorophyll was greater in normal leaf discs, but adding iron to chlorotic discs gave an incorporation rate almost equal to that of the normal . 2. Coproprophyrin accumulated in leaf discs that were incubated in the dark and infiltrated with 14C-labeled substrates. The concentration was markedly decreased when iron was added to the incubation media. Protoporphyrin was also found in low-iron culures but was not noticeably affected by the addition of iron. It was concluded that the conversion of coproporphyrinogen to protoporphyrin might be an iron-requiring site in the biosynthesis of chlorophyll in higher plants.