Morphology of Glandular Hairs of Cannabis Sativa From Scanning Electron Microscopy

Abstract

Three distinct types of glandular hairs of increasing morphological complexity which occur on flowering tops of Cannabis sativa L. (marihuana) are described from scanning electron microscopy. These gland types-termed bulbous, capitate-sessile, and capitate-stalked, described from pistillate plants-occur in greatest abundance on the outer surface of bracts ensheathing the ovary. Bulbous and capitate-sessile glands, which arise at an early stage in bract development, are scattered over the bract surface. Mature bulbous glands have a small swollen head on a short stalk, whereas capitate-sessile glands have a large globular head attached directly to the bract surface. Because of their numbers and large size, capitate-sessile glands are the most conspicuous gland type during the early phase of bract development. Capitate-stalked glands, which have a large globular head on a tall, multicellular stalk, differentiate during subsequent bract development. These stalked glands arise first along the bracteal veins and then over the entire bract surface. A voluminous, fluid secretory product accumulates in the glandular head of all three types. These glands are believed to be a primary site of localization of the marihuana hallucinogen, tetrahydrocannabinol.

Immunochemical localization of Tetrahydrocannabinol (THC) in Cryofixed Glandular Trichomes of Cannabis (Cannabaceae)

“…Cryofixation-cryosubstitution-Bract segments containing glands of different developmental ages, obtained from pistillate Cannabis plants grown under greenhouse conditions (Hammond and Mahlberg, 1973), were fixed and processed by the Balzers high pressure cryofixation (HPC) and cryosubstitution (CS) procedure. Small segments of fresh bracts were placed in brass Swiss Precision planchettes, immersed in 1-hexadecene (Sigma, St. Louis, MO), and immediately transferred to a Balzers HPM 010 for cryoimmobilization under a pressure of 2100 bar (Hunziker and Schenk, 1984).…”

Immunochemical localization of tetrahydrocannabinol (THC) in chemically fixed glandular thrichomes ofCannabis(Cannabaceae)

“…Therefore, in this study we examined the localization of the antibody in tissues prepared by CF to determine whether the THC probe would be retained in the secretory cavity, disc cells, and other cells in a pattern similar to that observed in HPC-CS tissues. Mahlberg, 1973). Tissues were fixed for 2 h at 4t in 4% glutaraldehyde containing 4% dimethylsulfoxide, rinsed in 50 mM sodium phosphate buffer (pH 7.2), and then postfixed for 1.5 h at room temperature with 2% osmium tetroxide vapor .…”

Pod Surface Characteristics in Wild and Cultivated Vigna Species and Resistance to the Coreid Bug Clavigralla tomentosicollis Stal. (Hemiptera: Coreidae)

“…Characteristics of trichomes on the pod surface Fresh pods (9-to 10-day-old) were collected from potted plants of the test genotypes to examine the length and density of glandular and nonglandular trichomes on the surface by means of a scanning electron microscope (SEM) (Model Phillips XL20 Series) at 10 kV accelerating voltage, SEM procedures used were those described by Hammond and Mahlberg (1973) with slight modifications in the dehydration of pod samples which was performed in different solvent mixtures (Table 1). Data were collected on the number of glandular and non-glandular trichomes per mm 2 , and on the length of the nonglandular trichomes.…”