Approaching the “secrets” of the resin ducts in the mastic tree (Pistacia lentiscus L. cv. chia)

Abstract

An extensive investigation on the resin duct network of the mastic tree (Pistacia lentiscus L. cv. chia) was undertaken in order to elucidate the origin, distribution and integration of the numerous resin-producing ducts within the plant and define some details missing from the investigations so far.The ducts in P. lentiscus cv. chia extend from the root tip, through the root and stem, to the leaves and the buds. They appear in the root apex long before the first xylem elements form. They are embedded in the clusters of the phloem cells which handle the sugar rich sap and the necessary for the duct development hormones. They hold-on to their connection with the phloem throughout their distribution within the plant body. The particular “rush” of the plant concerning the resin duct construction in the root – within the hostile soil environment – and the urgent energy support to the newly formed ducts, all over the plant body, indicate that there must be not just an important but a vital reason for the existence of these secreting structures. The resin ducts do not form a horizontal network; they do not split or merge unless they are in the leaves or in the pericarp. Idioblasts with crystals do not seem to appear in any of the primary plant organs. Further investigation on the interactions between the resin ducts and the rhizosphere and the benefit of this interrelation for the plant, is required in order to elucidate the “secret” of the secretion of a unique plant resin in a strictly confined area of the globe.