[Fine structure of mucus-secreting gland hairs on the ochrea of Rumex and Rheum]

The gland hairs on the ochrea in buds of Rumex and Rheum secrete a mucopolysaccharide which contains no acidic components (compare also KLING, 1961). These glands were studied by light and electron microscopy. The results are: The mucilage is secreted by the Golgi apparatus. The dictyosomes are relatively large; the secretory vesicles are connected with the Golgi cisternae by a network of tubules. It was proved by the silver methenamine method (comparable to the PAS reaction) that the Golgi vesicles contain a carbohydrate. The glutaraldehyde-OsO4-fixation preserves intercisternal fibrils between the Golgi cisternae. The dictyosomes show a polarity in the development of the cisternae which is not dependent on the stage of activity of the Golgi apparatus. The extruded mucilage accumulates in spaces between the cell wall and the cuticule. It penetrates the cuticule through pores of different sizes. The outer walls of the cells of the stalk and the walls between these cells are completely cutinized; therefore the stalk functions as a barrier in the apoplast. - Sometimes the nuclei contain spindlelike inclusions.