portion of plant substance plant resin plant_anatomy oleoresin (related) PO:0025603 Plant resins are often produced by Gymnosperms but not restricted to those plants. In the conifers, plant resins are constitutively and inducibly produced through the secretory activity of resin cells (PO:0025604), and can be exuded through a resin canal (PO:0005665) to a site of injury or predator attack. pitch (exact) CHEBI:24913 CHEBI:26873 A portion of plant substance (PO:0025161) that consists of a complex mixture of organic aromatic compounds such as mono-, sesqui-, and diterpenoids. Laurel_Cooper PO_GIT:587 2014-04-10T09:51:14Z