Nature, intracellular distribution and formation of terpenoid quinones in maize and barley shoots

Abstract

Maize and barley shoots have been shown to contain phylloquinone, plasto-quinone, [alpha]-tocopherol (and [gamma] -tocopherol in maize), [alpha]-tocopherol-quinone and ubiquinone-9. No solanesol was detected in any tissue examined. In maize shoots plastoquinone and a-tocopherolquinone were localized in the chloroplast; ubiquinone was in the mitochondria. Etiolated (dark-grown) shoots contained smaller amounts of phylloquinone and plastoquinone; [alpha]-tocopherolquinone was entirely absent; ubiquinone and [alpha]-tocopherol concentrations were unaffected. On illumination of etiolated shoots the chloroplastidic quinones phylloquinone, plastoquinone and [alpha]-tocopherolquinone were synthesized in step with chloroplast development. [alpha]-TocopheroIquinone was not formed at the immediate expense of [alpha]-tocopherol.