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

Abstract

Summary The distribution, anatomy and development of the resin duct system responsible for the resin exudation in Pistacia lentiscus var. chia D uhamel were investigated. Resin ducts are present in the stem, leaf and root located only in the phloem of the vascular bundles. They are tubular structures lined by a few layers of epithelial cells. Outwards the resin duct is well supported by arcs of sclerenchyma fibres. In the petiole and petiolule 5 resin ducts were found whereas in the mid vein of the leaflet 3 resin m 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 buds. Ducts are surrounded by numerous crystal idioblasts. All resin duct systems of the root and stem, though separated from one another, form a continuous system with the corresponding ones in the leaf. The inner layers of epithelial cells seem to decompose releasing their content into the duct lumen. In this space large masses of disorganized cytoplasm with many vesicles and organelles and wall remnants of the disintegrated cells could be found.