Distribution, development and structure of resin ducts in Pistacia lentiscus var. chia DUHAMEL

The distribution, anatomy and development of the resin duct system responsi ble for the resin exudation in Pistacia lentiscus var. chia DUHAMEL were in vestigated. Resin ducts are present in the stem, leaf and root located only in the phloem of the vascular bundles. They are tubular structures lined b y a few layers of epithelial cells. Outwards the resin duct is well support ed by arcs of sclerenchyma fibres. In the petiole and petiolule 5 resin duc ts were found whereas in the midvein of the leaflet 3 resin ducts are prese nt adjacent to vascular bundles. In the leaf primordium they are located in the mesophyll below the dense conductive palisade parenchyma. Furthermore resin ducts were found in the leaf-scales protecting the dormant lateral bu ds. Ducts an surrounded by numerous crystal idioblasts. All resin duct syst ems of the root and stem, though separated from one another, form a continu ous system with the corresponding ones in the leaf. The inner layers of epi thelial cells seem to decompose releasing their content into the duct lumen . In this space large masses of disorganized cytoplasm with many vesicles a nd organelles and wall remnants of the disintegrated cells could be found.