Trichome Types


Six forms of trichomes have been described, including: two types of non-glandular trichome,
 not been associated with terpenoid development; three types of glandular
trichome found on female cannabis plants: bulbous, sessile and capitate
stalked; and antherial glandular trichomes, which have only been found on anthers of male cannabis plants.


sessile and capitate stalked trichomes differed in their distribution, as well as their cannabinoid
content and profile


Simple unicellular trichomes
 These simple, non-glandular trichomes, also known as covering trichomes, are the first to appear on the plant.  They develop from a cell within the epidermis and are found on the surface of cotyledons beginning almost immediately after germination. These pubescent trichomes are sparse on the upper surfaces of the plant but continue to proliferate on the underside of leaves forming a covering on the underside of the leaf with a layer of trapped air between.  This acts as insulation for the plant, protecting it from extreme temperatures and reducing water loss during drought.


Cystolythic trichomes


Cystolythic trichomes form on the upper surface of the leaves beginning with the initial pair of true leaves on a cannabis seedling.  They always point toward the distal (outward) part of the leaf where they give the upper surface a texture that is rough to the touch. 
At the base of each trichome is a cystolyth (a concretions  formed from calcium carbonate
crystals.These tough trichomes would presumably reduce the palatability of the foliage to leaf-eating predators.











The cannabis plant has developed three main types of Trichomes:

Bulbous:

Bulbous Trichomes are the smallest (15 to 30 micrometers and least abundant.  Just one to four cells make up the ‘foot’ and ‘stalk’ of bulbous trichomes, while one to four cells make up the ‘head’ of the gland. Head cells secrete resin made up of cannabinoids, terpenes and other related compounds that accumulate between the head cells and the cuticle.  As the gland matures, a nipple-like protrusion can form on the membrane as a result of  pressure from the accumulating resin. These bulbous glands are found scattered about the surfaces of the aboveground plant parts.



Capitate-Sessile:

 This second type of glandular trichome is larger (25 to 100 micrometers) and more numerous than the bulbous glands.    Named from the Latin caput, meaning "head" and the Latin sessilis meaning "sitting".  On immature plants, the capitae lie flush and conceal the stalk which is just one cell high.  The stalk connects the trichome to the mesophyl cells.  The larger globular head is usually composed of eight, but up to 16 cells that form a convex rosette.  These cells secrete cannabinoids and related compounds that accumulate between the rosette and its outer membrane. This gives it a spherical shape.


the glandular head itself acted as a powerful convex lens


The glandular head (or resin head) incorporates a disc of secretory cells at the base.
These appear to totally lack chlorophyll. Above the secretory cells, and below the
trichome’s outer membrane, is a chamber within which the secretory cells sequester a
resinous mixture that includes cannabinoids and essential oils


The glandular head (or resin head) incorporates a disc of secretory cells at the base.
These appear to totally lack chlorophyll. Above the secretory cells, and below the
trichome’s outer membrane, is a chamber within which the secretory cells sequester a
resinous mixture that includes cannabinoids and essential oils



Capitate-Stalked:

Cannabinoids are most abundant in the capitate-stalked glands.  The stalk  consists of a tier of secretory disc cells subtending a large non-cellular secretory cavity. During flowering, the capitate glands that appear on the newly formed plant parts take on a third form. Some of the glands are raised to a height of 150 to 500 micrometres when their stalks elongate. These capitate-stalked glands appear during flowering and form their densest cover on the female flower bracts [specialized leaves that cover the seeds]. They are also highly concentrated on the small leaves that accompany the flowers. The male flowers have some stalked glands, but they are smaller and less concentrated than on the female.


Antherial Sessile Trichomes
Antherial Sessile trichomes are adistinct form of trichome that appear only on male plants. They are much larger than other sessile trichomes with a diameter of approximately 70-80μm.  these unique sessile trichomes were significantly larger than those located elsewhere. Sessile trichomes are found on the anthers of male plants and the  calyx surrounding these anthers.  Normal, smaller trichomes are also found on the calyx but in less abundance.





 


The remaining component in explaning how or why cannabis displays such medicinal and psychoactive affects is to understand the role that trichomes play in producing the plants active chemicals.  Trichomes are very tiny, often glanduar outgrowthss found on plants, algae, lichens, and certain protists.  They gain their name from the Greek τρίχωμα (thrix), meaning hair. While it is true that many trichomes are fine and hair-like, they can be found in a multitude of various forms including glands, scales and papillae depending upon the plant.  More than three hundred different types of trichomes have been described. 
 

When observed on the cannabis plant, trichomes take the form of glistening translucent glands that protrude from the brachts on buds, also on leaves and, less abundantly, on the central stalk and stems.  They are very small, only about 50 to 100 micrometers wide; some are made up of just a couple of cells.


It is believed that trichomes evolved as a natural defense mechanism for plants.  In cannabis, sticky trichomes form an adhesive-like layer over plant surfaces.  This protects the flowering plant (and its seeds) from potential predators and disease.  First, it repels insects and makes it more difficult for them to reach the plant surfaces.   The volatile chemicals manufactured within the trichomes protects against foraging animals by making the aroma and taste of the plant unpalatable.   This resin also helps to insulate the plant from wind, low humidity, and sun damage from  UV-B light rays.  In addition, the covering layer of trichomes insulates the plant from temperature extremes and inhibits the growth of fungus.


But the most important function of trichomes, at least from the perspective of its medicinal benefits and psychoactive effect, arises from their role in the manufacture of the chemical substances that confer cannabis give it its medicinal and psychoactive effects. The majority of the plant's resin is manufactured and stored within glandular trichomes.  The active ingredients of cannabis, including terpenes, THC and other the cannabinoids, are likewise brewed within trichomes.





Despite their minute size, it’s hard to miss the blanket of crystal resin on a cannabis bud. This resin (or “kief” when dry) is secreted through translucent, mushroom-shaped glands on the leaves, stems, and calyxes. Trichomes were originally developed to protect the plant against predators and the elements. These clear bulbous globes ooze aromatic oils called terpenes as well as therapeutic cannabinoids like THC and CBD. The basis of hash production depends on these trichomes and their potent sugar-like resin.

Capitate stalked trichomes have two main parts: the stalk and the gland head.

The epidermal cells hold up the mature trichome forming the outside of the stalk, and a continuous layer extends over the entire bract surface. The hypodermal cells on the inside of the stalk constantly transport nutrient) to the gland head. The basal cell at the top of the stalk holds on to the gland head. As the flower matures, and as mature flowers dry, this connection weakens and gland heads tend to fall off.

At the base of the gland head are stipe cells, which hold up the secretory cells. Secretory cells take the nutrients from the phloem and turn them into precursors for cannabinoid and terpenoid metabolism. The theory is that these precursors get transported to the secretory vesicles above, and are converted into cannabinoids and terpenoids once they’re there.

As the gland head churns out its product, the resin gets deposited, and up close to the cuticle, the outer layers of trichome surface. The cuticle, thickens getting richer and richer in oil as flowering progresses.

The essential oils, including THC, mostly accumulate on the outer layer of the gland head, but also on the outer layer of the epidermal cells that cover the entire bract, or any trichome-dense area. Resinous THC also accumulates in the fibrillar matrices (pardon the jargon) of the secretory vesicles. Inside these vesicles there is some THC, but also high amounts of terpenoids, which are less viscous.Type your paragraph here.

they house the majority of its resin.

Every part of the cannabis plant has at least a little THC in it. Leaves have around 4%, while buds have up to 25% or 30% of dry weight. The trichomes cover all parts of the buds, from the interior stems to the surrounding leaves.

Scientists used to think that THC and other cannabinoids were made in the green plant tissue and transported out to the trichomes during flowering, but after intensive research, they realized that the trichomes themselves make the cannabinoids and terpenes.

THC and other cannabinoids are produced in only one place on the cannabis plant: inside the heads of the trichomes. How it happens: Organelles produced by the plant called Vacuoles – which contain phenols, a chemical compound similar to alcohol [pictured at right in blue], and another type of organelle called plastids – containing hydrocarbons called terpenes [red], make their way up the trichome stalk [green] and combine inside the secretory cavity into a fibrous mat [yellow]. This concentrated mat is hit by UV-B light waves, causing the creation of cannabinoids.

The epidermal cells hold up the mature trichome forming the outside of the stalk, and a continuous layer extends over the entire bract surface. The hypodermal cells on the inside of the stalk constantly transport nutrients (http://en.wikipedia.org/wiki/Phloem) to the gland head. The basal cell at the top of the stalk holds on to the gland head. As the flower matures, and as mature flowers dry, this connection weakens and gland heads tend to fall off.

At the base of the gland head are stipe cells, which hold up the secretory cells. Secretory cells take the nutrients from the phloem and turn them into precursors for cannabinoid and terpenoid metabolism. The theory is that these precursors get transported to the secretory vesicles above, and are converted into cannabinoids and terpenoids once they’re there.

As the gland head churns out its product, the resin gets deposited, and up close to the cuticle, the outer layers of trichome surface. The cuticle, thickens getting richer and richer in oil as flowering progresses.

The essential oils, including THC, mostly accumulate on the outer layer of the gland head, but also on the outer layer of the epidermal cells that cover the entire bract, or any trichome-dense area. Resinous THC also accumulates in the fibrillar matrices (pardon the jargon) of the secretory vesicles. Inside these vesicles there is some THC, but also high amounts of terpenoids, which are less viscous.

How Cannabis Works: TRICHOMES