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. And yet it has never been described in detail, particularly in regard to its secretory structures. The present research uses optical and electron microscopy to identify the laticifer cells in all plant organs, including the roots, where such cells had never previously been reported. Moreover, as opposed to what has been described in similar studies, these laticifer cells are articulated. In addition, histochemical tests were performed to identify the alkaloids in the latex and to quickly identify the same laticifer tissues in fresh samples. These tests always proved positive, indicating a close relationship between laticifer cells and the presence of alkaloids in the plant. TEM also showed that the laticifer cells have well-preserved cytoplasm and organelles which lead one to conclude that metabolic activity is still intact