Beiträge zur Physiologie der Alkaloide: III. Chelidonium majus L. und Sanguinaria canadensis L.: Ultrastruktur der Alkaloidbehälter, Alkaloidaufnahme und -verteilung

Abstract

Latex cells of Chelidonium majus are characterized before they fuse to latex vessels. Young cells contain besides the nucleus a highly vacuolated plasma, dictyiosomes, numerous mitochondria and small plastids. Embedded in the groundplasm and in small vacuoles are particles of unknown quality (diameter 0.3−0.6 μm). Latex particles are rare, they are found in the ground-plasm. The ultrastructure of the latex cells changes drastically in a later stage even before fusion starts: The number of vacuoles increases, the organelles degenerate, the groundplasm becomes osmiophile to such an extend that it is difficult to identify cellular membranes with the usual technique of preparation (glutaraldehyde/osmium tetroxide). Isodiametric alkaloid containing cells are abundant in the rhizome of Sanguinaria canadensis. There are rather large cells (150−200 μm in diameter) which are coloured by sanguinarine. Fully differentiated cells are characterized by a large central vacuole and a thin protoplasmic layer. The groundplasm becomes osmiophile, the structure of the organelles disappears and even the tonoplast and the plasmalemma are no longer visible as typical unit membranes after fixation with glutaraldehyde/osmium tetroxide. Localization of endogenous alkaloid can be demonstrated, using a method of fixation, elaborated previously in our laboratory. In Chelidonium the alkaloid is found inside the small vacuoles and along the cell walls of the latex vessels. In Sanguinaria the alkaloid is depointed inside the central vacuoles. Leaf tissue of Chelidonium majus accumulates protopine-T, supplied exogenously. About 70 % of the alkaloid is bound to the thickenings of the xylem vessels 1 hour after feeding. The rest of the alkaloid is rather evenly distributed among the other cells of the leaf. The picture changes 3 hours after pulse feeding of radioactive alkaloid. Again the thickenings of the xylem vessels are labelled, but besides these structures only the latex vessels contain radioactive tracer. In Sanguinaria a preferential accumulation of alkaloid in the alkaloid cells can be demonstrated too. The alkaloid cells contain 4 times as much silver grains per unit of area in autoradiographs as the neighbouring cells. The cell walls are labelled too. This tissue of Sanguinaria rhizomes is able to accumulate alkaloid above the concentration of the experimental solution as demonstrated preparatively. Azide does not inhibit accumulation. Dinitrophenol is an inhibitor in higher concentrations (10−4 M/l) only.