Etioplasts of dark-grownAvena sativa plants were used to prepare either saponin-free or saponin-containing prolamellar bodies. Lipid extracts from both fractions were studied in reaggregation experiments: extracts containing saponins showed liposomes as well as tubules, while saponin-free samples formed only liposomes. Purified PLB lipids in reaggregation experiments were either studied in the presence or in the absence of saponins. Best tubule formation was found with samples containing MGDG+saponin. However, the reconstruction of PLB-like structures was not possible. The long tubules, protruding from isolated PLBs, are seen as a result of the reaction of saponins (originally located in vacuoles) with MGDG.

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