“Elaioplasts” of Haemanthus albiflos are true lipotubuloids: cytoplasmic domains rich in lipid bodies entwined by microtubules

Abstract

In the cells of Haemanthus albiflos leaf epidermis there are structures containing lipids analogous to “elaioplasts” (Wakker in Jahrb F Wiss Bot 19:423–496, 1888). Ultrastructural analysis has shown that they are cytoplasmic domains—lipotubuloids, since they exhibit all the features of Ornithogalum umbellatum lipotubuloids. They are composed of numerous lipid bodies surrounded by microtubules, ER cisternae and vesicles, some mitochondria, Golgi structures, and microbodies. In the center of some lipotubuloids there are also autolytic vacuoles. Microtubules adjacent to H. albiflos lipid bodies were revealed only when taxol preincubation was used before fixing the epidermis in the mixture of glutaraldehyde and OsO4. The presence of tubulin in H. albiflos and O. umbellatum lipotubuloids was confirmed with use of the immunogold method involving antibodies against tubulin α. It is possible that the association of microtubules with lipid bodies may be more common than originally thought, but it is difficult to reveal due to the methodological problems.