[Investigations on the physiology of the glands of carnivorous plants : V. Microautoradiographic investigations of chloride secretion by the gland tissue of Nepenthes].

The secretion of (36)Cl(-) by tissue isolated from Nepenthes pitchers was investigated with microautoradiographic techniques. The tissue was transferred into ether at-30°C or embedded in the vacuum, following procedures described earlier (LüTTGE and WEIGL, 1965).The microautoradiographs which we obtained after application of 1-10 mM chloride solutions to the surface corresponding to the outside of the pitchers showed a high labelling of the gland cells, the cell borders in the mesophyll (i.e. the cell walls including the thin plasmatic layers), plasmatic particles and the conductive tissue. The gland cells have only very small vacuoles and are densely filled with cytoplasm. The grain counts show that the radioactivity in the parts of the tissue which are rich in cytoplasm (glands, cell borders, plasmatic particles) did not differ within the statistical error. The activity of the vacuoles, however, was much less.These findings are discussed in the light of ARISZ' theory of symplasmatic transport. However, an artificial transfer of the radioactivity contained in the large vacuoles of the mesophyll cells to the cytoplasm during the preparation can not be entirely excluded.