Laticifer tissue distribution and alkaloid location in Vinca sardoa (Stearn) Pign. (Apocynaceae), an endemic plant of Sardinia (Italy)

Vinca sardoa (Apocynaceae) is an endemic plant of Sardinia (Italy) used in local folk medicine. Yet it has never been described in detail, particularl y in regard to its secretory structures. The present research uses optical and electron microscopy to detect the laticifer cells in all plant organs, including the roots, where such cells had never previously been reported. M oreover, as opposed to what has been described in similar studies, these la ticifer cells are articulated. In addition, histochemical tests were perfor med to detect the alkaloids in the latex and to quickly identify the same l aticifer tissues in fresh samples. These tests always proved positive, indi cating a close relationship between laticifer cells and the presence of alk aloids in the plant. TEM also showed that the laticifer cells have well-pre served cytoplasm and organelles which lead one to conclude that metabolic a ctivity is still intact.