FINE STRUCTURE OF OIL GLANDS .4. OIL CHANNELS OF UMBELLIFERAE - HERACLEUM SPHONDYLIUM AND DOREMA AMMONIACUM

The oil channels of Heracleum sphondylium and Dorema ammoniacum were studied by electron microscopy in different stages of development with regard to the excretion process. Characteristic features of the Heracleum gland cells are a smooth endoplasmic reticulum consisting of a network of tubules, elements of the endoplasmic reticulum which envelope partly the leucoplasts, and irregular tubular structures within these plastids. The dictyosomes extrude secretion vesicles which may contain wall substances and the mucilagous constituents of the excretion. The content of the channel is poorly preserved in its arrangement. The gland cells of Dorema have a similar structure. There are certain differences in the content of the channel. The tubular elements within the leucoplasts are more prominent. The smooth, tubular endoplasmic reticulum is not so conspicuous. The results were compared with other reports, and possibilities for the way of the excretion were discussed. © 1969 Springer-Verlag.