Fine Structure of the Chromoplasts of Fruit of Solanum aviculare Forth. var. brisbanense

Abstract

Chromoplasts of ripe fruit of Solanum aviculare contain a large number of electron-translucent structures, which distinguishes them from the chromoplasts of many other species. During the chloroplast-chromoplast transformation, starch and grana disappear and plastoglobules accumulate. As ripening progresses, the plastoglobules fill with increasing amounts of electron-translucent structures which then protrude from the plastoglobules and eventually form a single small slab-shaped structure, and the plastoglobule disappears. β-Carotene (86.4%) is the main carotenoid of the ripe fruit, and small amounts of lutein, zeaxanthin, phytofluene, mutatochrome and neoxanthin are present. On the basis of carotenoid composition and appearance under the electron microscope, it is concluded that the translucent structures consist of a crystalline form of β-carotene.