Biology and Chemistry of Plant Trichomes, 23-51
Paul G. Mahlberg, Charles T. Hammond, Jocelyn C. Turner & John K. Hemphill
Department of Biology, Indiana University, Bloomington, IN 47405
Keywords: Cannabis sativa, Cannabaceae, cannabinoids, gland, development, structure
The glandular secretory system of the Cannabis sativa L. is composed of bulbous, capitate-sessile and capitate-stalked glands which are distinguishable from each other by morphogenesis and physiology. Bulls and capitate-sessile forms occur on that Judas and floral axes whereas the highly evolved capitate-stalked form is present only on floral related organs. In studies of cloned plants, Gland and initiation occurred on leaves and pistillate bracts throughout organ ontogeny. Gland density and time of appearance very between both clones and organs, indicating that control of development is independent for each trichome type. Cannabinoid synthesis also occurred throughout the organ ontongeny but with a decreasing rate in leaves as compared to an increasing rate bracts. In individual glands, cannabinoid content decreased during maturation. Capitate-stalked glands contain higher cannabinoid levels then the sessile form although the glands maintained the profile characteristic of the clone. Analysis of glands in tissues indicated cannabinoids may occur in cells other than glands. Capitate glands develop a disk of secretory cells , and secretions accumulate in a cavity beneath a sheath derived from separation of the cuticularised outer wall surface of the disc cells. Presume secretions, including cannabinoids, occur at the surface of plastids and appeared to migrate to the cell surface adjoining the secretory cavity. Self fractionation studies are in progress to define the cannabinoid synthesizing activities with in the dynamic glandular system of Cannabis.