Ultrastructural Development of Capitate Glandular Hairs of Cannabis Sativa L. (Cannabaceae)

Abstract

The capitate‐sessile and capitate‐stalked glands of the glandular secretory system in Cannabis, which are interpreted as lipophilic type glandular hairs, were studied from floral bracts of pistillate plants. These glands develop a flattened multicellular disc of secretory cells, which with the extruded secretory product forms the gland head and the auxiliary cells which support the gland head. The secretory product accumulates beneath a sheath derived from separation of the outer wall surface of the cellular disc. The ultrastructure of secretory cells in pre‐secretory stages is characterized by a dense ground plasm, transitory lipid bodies and fibrillar material, and well developed endoplasmic reticulum. Dictyosomes and dictyosome‐derived secretory vesicles are present, but never abundant. Secretory stages of gland development are characterized by abundant mitochondria and leucoplasts and by a large vacuolar system. Production of the secretory product is associated with plastids which increase in number and structural complexity. The plastids develop a paracrystalline body which nearly fills the mature plastid. Material interpreted as a secretion appears at the surface of plastids, migrates, and accumulates along the cell surface adjoining the secretory cavity. Extrusion of the material into the secretory cavity occurs directly through the plasma membrane‐cell wall barrier.

Development, oil storage and dehiscence of peltate trichomes in Thymus vulgaris (Lamiaceae)

“…A raising process of the cuticular sheath comparable to that observed in thyme was described in Cannabis (Hammond & Mahlberg 1973, De Pasquale 1974, while in Monarda it was observed that the head cells shrink and no cuticular distension occurs (Heinrich 1973). In thyme the formation of a sub-cuticular space causes distinctive cell wall changes.…”

Cytochemical localization of cellulase in glandular trichomes ofcannabis (cannabaceae)

“…More recently it was shown that a subcuticular wall, including a possible cellulosic component, is present under the cuticle (Hammond and Mahlberg, 1978;Mahlberg et al, 1984). Our morphological studies show the presence of a subcuticular wall originating from a periclinal splitting of the outer disc cell wall to form an intrawall secretory cavity (Kim and Mahlberg, 1991).…”

GLANDULAR CUTICLE FORMATION IN CANNABIS (CANNABACEAE)

“…Vesicles in the secretory cavity, examined by HPC-CS, possessed a distinctive surface feature approximately onehalf the thickness ofa typical bilayered membrane. In CF a bilayered membrane was detected around vesicles during the formative phase of the secretory cavity, whereas only a single-layered feature surrounded vesicles later in cavity development (Hammond and Mahlberg, 1978;Kim and Mahlberg, 1991;Mahlberg and Kim, 1991). The presence of a single-layered feature around secretory vesicles, rather than a bilayered membrane, may reflect the interaction of lipophilic contents of vesicles with other components, possibly proteins, which are reported in the cell wall (Fry, 1988).…”

“…Bract segments containing glandular trichomes at different stages ofdevelopment were obtained from pistillate Cannabis plants grown under greenhouse conditions (Hammond and Mahlberg, 1973).…”