Inside the Trichome

CANNABIS CULTURE - An up-close look at the THC-producing resin glands of the cannabis plant through pot-ographer Bubbleman's macro lens.

If you’ve seen pictures of mature cannabis plants taken with a macroscopic lens that’s zoomed-in very close, then you’ve undoubtedly noticed the many glistening translucent resin glands protruding from the buds, leaves, and just about everywhere else on the plant (see “Stalking Trichomes”, CC #72). Most marijuana growers and readers of pot magazines are quite familiar – and some downright obsessed – with these resinous outgrowths known as trichomes. You may have also read that the sticky coating of trichomes is home to the active ingredients in cannabis – the stuff that gets you high and has all the medical benefits – tetrahydrocannabinol (THC), cannabidiol (CBD), and other cannabinoids. But have you ever wondered exactly what the trichomes do for the cannabis plant, or what biological purpose they serve?

Sticky resinous growths knows as trichomes are home to the active ingredients in cannabis. (Click picture to enlarge)Sticky resinous growths knows as trichomes are home to the active ingredients in cannabis. (Click picture to enlarge)Evolution of Trichomes

In nature, only the strong survive, and it is hypothesized by biologists that trichomes evolved as a defense mechanism of the cannabis plant against a range of potential enemies (1). Trichomes, from the Greek meaning ‘growth of hair,’ act as an evolutionary shield, protecting the plant and its seeds from the dangers of its environment, allowing it to reproduce. These adhesive sprouts form a protective layer against offensive insects, preventing them from reaching the surface of the plant. The chemicals in the trichomes make cannabis less palatable to hungry animals and can inhibit the growth of some types of fungus. The resin also helps to insulate the plant from high wind and low humidity, and acts as a natural ‘sun-screen’ in protecting against UV-B light rays. But since trichomes contain euphoric properties attractive to humans, it may be man who has had the most influence on the plants’ development through many years of favoring strains that consistently produce more of these gooey resin heads.

Trichome Types

Trichomes grow in numerous shapes and sizes on many types of plants. The cannabis plant has developed three main types (from NationMaster Encyclopedia):

Bulbous: This type is the smallest (15 to 30 micrometers). From one to four cells make up the ‘foot’ and ‘stalk’, and one to four cells make up the ‘head’ of the gland. Head cells secrete a resin, presumably cannabinoids, and related compounds that accumulate between the head cells and the cuticle. When the gland matures, a nipple-like protrusion may form on the membrane from the pressure of accumulating resin. The bulbous glands are found scattered about the surfaces of the aboveground plant parts. [Pictured below.]

Capitate-Sessile: The second type of gland is larger (25 to 100 micrometers) and more numerous than the bulbous glands. They are called capitate, which means having a globular-shaped head. On immature plants, the heads lie flush, appearing not to have a stalk and are called capitate sessile. They have a stalk that is one cell high, although it may not be visible beneath the globular head. The head is composed of usually 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.

Capitate-Stalked: Cannabinoids are most abundant in the capitate-stalked glands, which 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. (2)

Cannabinoids

Cannabinoids are a group of chemical compounds that occur naturally in the cannabis plant, first discovered in the 1940s. When consumed by humans, the chemicals bind to CB1 and CB2 cannabinoid receptors in the brain and body, causing euphoria and other effects. The broader definition includes three general types: phytocannabinoids, which occur uniquely in the cannabis plant; endogenous cannabinoids, produced by the bodies of humans and other mammals, birds, fish, and reptiles; and synthetic cannabinoids, which are related compounds produced in laboratories. Cannabinoids present in the cannabis plant include THC, CBD, cannabinol (CBN), cannabichromene (CBC), cannabigerol (CBG), and tetrahydrocannabivarin (THCV).

Inside the Trichome

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. Since all of the psychoactive ingredients are produced inside the trichome, these tiny resin hairs have long been sought after by hash and oil makers and can be separated from the plant and harvested in a variety of ways (3).

Potency and Tricomes

Many media outlets and politicians say the ‘potency’ of today’s pot has increased dramatically in the last 30 years, claiming it contains anywhere from 10%-40% THC. Most are dubious claims, as it is quite obvious that a sample of herbal plant material does not consist of nearly half THC, but there is still much debate on the issue of potency classification. One thing is for sure; heavy trichome production does not necessarily mean higher potency, because the resins inside the trichome may or may not contain high levels of THC and other active ingredients. Some speculate that the percentage levels refer to the amount of THC in the oils produced inside the resin glands, but new studies show that cannabinoids other than THC also have distinctive effects on brain functions and cause correspondingly different effects on human cognition and psychiatric symptoms (4). This makes gauging the ‘potency’ or ‘strength’ of cannabis plants very difficult, as different cannabinoid level combinations may induce different types of highs. (For more information, see “Pot Potency” CC #34.)

Click pictures to enlarge

Dry Sift

There are many ways to separate the trichomes from the plant to make hash, oil and butters, or to smoke directly as dry-sifted kief (see “How To Make Hash”, CC #69). Fine mesh screens and products like BubbleBags assist in the extraction process. When it comes to dry-sifted trichomes, it is very difficult to completely separate the resin heads from the stalk and other waste product of the plant. (See “Bubbleman’s Trichome Meltdown”, CC #73) The dry sift shown here is nearly 100% glandular heads and was extracted using the Sam the Skunkman method that even our CC hash experts have yet to figure out.

Click pictures to enlarge

Sources:

(1.) “Trichomes and Insects” by Thomas Shanower,
Encyclopedia of Entomology.
http://www.ars.usda.gov/research/publications/
publications.htm?seq_no_115=165979

(2.) “Trichomes”, NationMaster Encyclopedia.
http://www.nationmaster.com/encyclopedia/Trichome

(3.) “THC (Tetrahydrocannabinol) Accumulation in Glands of Cannabis (Cannabaceae)” by Paul G. Mahlberg and Eun Soo Kim, Department of Biology, Indiana University, Bloomington,
IN USA; and Department of Biology, Konkuk University,
Seoul, Korea
http://www.hempreport.com/issues/17/malbody17.html

(4.) “Cannabis and the misleading concept of potency”,
Canna Zine News.
http://pr.cannazine.co.uk/20090130846/cannabis-news/cannabis-and-the-lis...

 

Comments

Great article

this was very interesting to learn or learn more about the marijauan plant it self.

That last picture is just

That last picture is just crazy. My mouth is starting to water.

This article is probably the

This article is probably the best you have ever published.
Everything about marijuana boils down to things concerned with the trichomes and their proper development on the plant.I am so crazy about trichomes I would be willing to do an entire Ph.D. on this topic.Trichomes are not unique to cannabis. Oil is produced by these structures in other plant genus and I know efforts are underway to increase the oil production in the trichomes. Think of all the fine genetic tuning required and all the genes in action that lead to the development of such structures.This is absolutely mind-boggling. Think also about the potential of having such structures growing in tissue culture flasks.
I recently had the unique opportunity to see and examine upclose the trichomes on flowering AK-48 strain with the help of a 10X photo magnifier.It was such a fascinating experience to see those transluscent head trichomes change slowly and becoming milky and take up amber tint with time and the reddish pistils.Not to mention the honey and sooooo sweet smell of the flowers.This experience has changed my life forever and made me revised my conception of the plant.How can such beauties be hidden on the surface of a plant and deep within the female flowers remain a mystery to me and why is this plant cannabis subjected to so much hate and misunderstanding is beyond my understanding. Cannabis is in my view more beautiful than the rarest orchid on Earth and I vote for it as the most beautiful of the entire plant kingdom.Being a hobby photographer,in the future I am planning to learn about microphotography and in my turn immortalize the trichomes and reddish pistils.
In my wildest dreams I never thought I could fall one day in love with a female cannabis plant.I urge everyone not to miss this occasion of looking at trichomes. As a matter of fact full development and the presence of trichomes is the best indication of many sweet dreams to come...

hell ya

hey bb54 ..... couldn't have said it better myself.. truly amazed at this wonder of the world ..God truly knew wut he wuz doin here.. for shur hear 4 a reason

Yes God is AMAZING!

here is evolution: from the gooo to the zoo now your You! hehehe now thats faith!! LOL

It's a beautiful thing

So why is such an amazing plant, with so many uses and positive effects on human life, surrounded by such stigma? Could marijuana save the world?

No UV in HPS or LED and yet

No UV in HPS or LED and yet there's still THC in plants grown under them. How is that possible?

Because there is UV LED's

Because there is UV LED's mixed with the RGB ones.

You wrote about bulbous:

You wrote about bulbous: "Head cells secrete a resin, presumably cannabinoids, and related compounds"

But then you write underneath: "THC and other cannabinoids are produced in only one place on the cannabis plant: inside the heads of the capitate-stalked trichomes."

Is THC/cannabinoid production only in the head of the capitate-stalked or also in the first type of trichome, the bulbous, as well?

Corrected. Thanks for tip

This article has been corrected to remove "capitate-stalked" from the section you mentioned.

Advertisement

Advertisement

Related Articles

Subcool, Cannabis Culture
Oct 15 2009
CANNABIS CULTURE - Master grower Subcool on trichome production, THC levels, and the best time to harvest your blossoming buds.
Cannabis Culture Readers
Aug 21 2009
CANNABIS CULTURE - Cannabis Culture readers send us their bud and garden shots.
Jason King, Cannabis Culture
Aug 3 2009
CANNABIS CULTURE - Sour Grape Haze is a massive multi-hybrid from Grass Valley, California.

Advertisement

Advertisement

Advertisement