Plant substance is a term used to describe any organic material that is produced by plants. Two examples of plant substances are RESIN and pentosan. RESIN is a sticky, yellowish-brown substance that is secreted by certain trees and plants. It is often used in the production of varnishes, lacquers, and adhesives. Pentosan is a polysaccharide found in the cell walls of plants. It is used in the production of paper, textiles, and food products.