title: The presence and synthesis of the NADPH-protochlorophyllide oxidoreductase in barley leaves with a high temperature-induced deficiency of plastid ribosomes.
abstract: High-temperature-induced deficiency of plastid ribosomes in barley plants (Hordeum vulgare L.) was used as a system for studying the role of the cytoplasm in the synthesis of the NADPH-protochlorophyllide oxidoreductase. The enzyme is present in 33° C-grown plants. The failure of high-temperature-grown plants to accumulate chlorophyll during illumination is not caused by the absence of the protochlorophyllide-reducing enzyme. The synthesis of the NADPH-protochlorophyllide oxidoreductase was studied by feeding [(35)S]methionine to the seedling and by following the incorporation of the radioactively labeled amino acid into plastid proteins. The NADPH-protochlorophyllide oxidoreductase was labeled in high-temperature-grown barley plants to the same extent as in control plants grown at 25° C. It is concluded that the 36,000-Mr polypeptide of the NADPH-protochlorophyllide oxidoreductase is synthesized outside the plastid on cytoplasmic 80S ribosomes.
authors.affiliation: Biologisches Institut II der Universität, Schänzlestrasse 1, D-7800, Freiburg, Federal Republic of Germany.
authors.forename: A
authors.initials: A
authors.lastname: Batschauer
authors.forename: H J
authors.initials: HJ
authors.lastname: Santel
authors.forename: K
authors.initials: K
authors.lastname: Apel