This is the second part of a nine-part series detailing the cannabis extraction market and processes used to extract desirable compounds from the cannabis plant.
In this part of the series, we start by providing an overview of the cannabis plant, investigating the anatomy of the plant and which components are desirable for cannabis concentrates. To navigate to other parts of this cannabis extraction series, follow the links below:
Part I: Cannabis Extracts Market
Overview of the Cannabis Plant
Developing an overview of the cannabis plant can be done in multiple ways. The plant can be analyzed based on its anatomy, genetics, and molecular structure. Naturally, all of these aspects of the cannabis plant are interconnected and have a direct impact on the other features. For example, when looking at the cannabis plant on the genetic level, the first comparison is often made between male and female plants. The distinction of a cannabis plants sex will impact its anatomical structure which in turn affects the molecular makeup of the plant. This will be illustrated by examples throughout this reading.
Cannabis Anatomy
The anatomical analysis of the cannabis plant focuses on its bodily structure, which is comprised of roots, the main stalk, lateral branches, cotyledon leaves, fan leaves, flowers, and seeds. These categories of the anatomical structure of cannabis can be further broken down, however, for the purpose of this analysis, we will look at these broad categories.
Roots
The cannabis plant depends on its roots to provide a physical anchoring system that will allow the plant to grow big and tall, much like a deep building foundation provides the support for a tall building.
Additionally, as part of the plants’ vascular system, roots draw nutrients from the soil into the cannabis plant. Xylem is a transport tissue that acts as the plants plumbing system and is responsible for pumping water and minerals from the roots to the rest of the plant.
The root zone is comprised of a single tap root which is the first anatomical structure to emerge from a germinated seed. The taproot will develop many secondary roots until it results in a fibrous mass capable of simultaneously providing support for the plant and acting as the nutrient delivery system.
Main Stalk & Lateral Branches
Once the taproot has been established the main stem will emerge vertically from the roots. The main stem supports all the additional growth of the cannabis plant and acts as the primary vascular highway, carrying the water and nutrients from the roots to the rest of the plant.
The main stem will develop leaf nodes, where secondary growth emerges and branching occurs. Pairs of branches will form at each leaf node which typically form at consistent intervals referred to as the internodal spacing. The plants’ genetics have a large impact on the internodal spacing which will be touched on later in this reading.
Leaves
Cannabis is classified as a dicotyledon, or “dicot” plant, a flowering plant with an embryo that contains two cotyledons. These leaves are responsible for performing photosynthesis in the early stages of growth.
Fan leaves are the iconic serrated leaves which undertake most of the plants’ photosynthesis during its vegetative and flowering phases. Similar to the lateral branches, fan leaves will emerge in sets of two from the main stem and branches, and will have an increasing odd number of leaflets, starting with a single leaflet on the first pair, followed by 3, 5, 7 and so on, on the subsequent leaves.
As stated, the fan leaves function as solar panels, converting light energy into chemical energy via photosynthesis. The leaves also act as an air conditioning system via stomata, tiny pores on the underside of the leaf which absorb CO2 and open and close in response to changing temperature and humidity levels. The plants’ genetics will dictate the size, shape, and colour of fan leaves.
Flowers
Cannabis flowers are the most sought after anatomical structure of the cannabis plant due to their high concentrations of cannabinoids (more on these later). Cannabis is a dioecious plant, meaning the male and female reproductive organs grow on different plants.
The exception to this rule occurs in hermaphroditic plants which are commonly attributed to one of two origins: genetic and environmental. Some genetics are more sensitive to hermaphroditism than others, and some environmental conditions may place enough strain on the plant during the flowering phase that it naturally attempts to shorten the flowering period by pollinating its female flowers with pollen of a male cluster.
Female Cannabis Flowers
Most cannabis growers are solely focused on the production of female pistillate flowers due to their high concentration of cannabinoids and terpenes. While most flowers form at budding sites on the lower branches, the main cola, which is typically the largest flower, forms at the top of the plant. If a plant is subjected to one of many training techniques during its vegetative phase, a plant may have multiple tops where equally large colas develop.
The female flower is formed of tight clusters of bracts (or calyxes) which encapsulates the pistil containing the reproductive parts of a flower. The calyxes appear as green tear-shaped “leaves” and protect the pistils. Pistils contain hairlike strands called stigmas which serves the purpose of catching airborne pollen from male cannabis plants. If pollen is transported to the ovary, seeds will form, filling the bracts as they grow. The collection of pollen and production of seeds is the natural purpose of female cannabis flowers, however, most growers try to avoid pollination because once a flower becomes pollinated it diverts energy towards the production of seeds at the expense of resin production. This results in lower yields in terms of mass, and in terms of cannabinoid and terpene levels.
Resin is produced primarily in glandular trichomes. Trichomes have the function of protecting the flowers and immature seeds from harsh UV light, insects, and grazing animals, but also secrete desirable cannabinoids and terpenes. Non-glandular trichomes form on stems and leaves, while glandular trichomes mainly form on the calyxes of the flowers and surrounding sugar leaves. As the flowers mature, the trichomes colour transitions from translucent to milky white, to an amber colour which signifies that the flowers are fully mature and ready for harvest.
Male Cannabis Flowers
Although the presence of male cannabis plants can be cause for alarm for many growers, it is important to understand their purpose and anatomical differences in comparison with female flowers. Male (staminate) flowers resemble small green balls which grow in long, loose bud clusters from internodes on the plants’ branches. Each ball is composed of five petals which, once mature, open to reveal pollen-producing stamens. The male flowers are packed with pollen, which when released can pollinate an entire field of female cannabis plants.
Although male cannabis plants are vital for the production of seeds, male flowers contain low levels of cannabinoids and terpenes, therefore most growers choose to grow from either feminine clones or feminized seeds. Even with feminized seeds, growers must remain vigilant to spot male pre-flowers and hermaphroditic plants to avoid pollinating their precious females.
Seeds
Inside each cannabis seed is an embryo of the plant which provides everything needed to start a new plant once the conditions of moisture and warmth are met to induce germination. Included in the embryo is the cotyledon leaves which are rounded embryonic leaves that contain the seeds food reserves for early development. The seeds contain all genetic information of the parent plants, which will impact the physical and chemical features of the plant.
Cannabis Genetics
Cannabis is a dioecious plant, meaning it produces separate male and female plants, allowing farmers to separate the plants before they become fertilized. As stated above, there are significant differences between male and female cannabis plants.
When flowering, male cannabis plants produce pollen sacs instead of flower buds. This leads to a very low THC content in the male cannabis plants because the highest concentration is usually found in resinous flower buds. Because of this, male plants are not desirable for commercial or personal uses. Female plants are more desirable for growers due to their ability to flower large buds with a much higher concentration of cannabinoids and terpenes.
You will need to collect the pollen from male plants in order to pollinate female plants if you want to produce seeds. However, most seed production is of the feminized variety which can be produced by spraying a female plant with hormonal solutions such as colloidial silver to generate feminized pollen.
Cannabis Sativa L. Subspecies
Sativa, Indica and Ruderalis are all subspecies of the Cannabis Sativa L. species. Any hybrid strains are a result of combining any of these three subspecies to enhance specific desirable traits.
Sativa
The Sativa subspecies are believed to have originated around equatorial regions, making it ideal for growing in warmer climates. Once fully grown, Sativa cannabis plants can reach up to 13 – 15 feet tall. They have narrow-bladed leaves, with long internodes and branches. Sativa plants have a longer vegetation period than Indica or Ruderalis strains, resulting in higher yields once harvested. However, on average Sativa strains have lower THC percentage than their Indica counterparts.
Indica
Originating in the mountain regions of Pakistan and Afghanistan, the Indica subspecies has fat and wide leaves. The plants grow shorter and fatter than Sativa strains, reaching anywhere from 2 – 6 feet in height, an ideal characteristic for indoor grow facilities. Moreover, they have an average flowering period of between 8 – 12 weeks depending on the specific strain. They also typically have a higher THC content than Sativa strains, but a lower overall yield at between 1.5 – 2.5 ounces per plant.
Ruderalis
Not as popular as Indica and Sativa, the Ruderalis subspecies is an auto-flowering cannabis plant believed to originate in parts of northern Asia, Russia, and Eastern Europe. Ruderalis plants will reach between 1 – 2.5 feet in height and can grow successfully in harsh environments.
On their own, Ruderalis plants do not have a high enough THC content for commercial uses, but they do have an extremely valuable trait; auto-flowering. This means their flowering is induced by the maturity of the plant rather than the photoperiod, as is the case with Indica and Sativa strains. By breeding 20% Ruderalis genetics into Indica or Sativa strains, breeders can create hybrid auto-flowering strains that have a higher THC content than Ruderalis would have on its own.
Compounds of Interest
The cannabis plant is known to contain at least 113 cannabinoids, the most well known of which are tetrahydrocannabinol (THC) which is the psychoactive component of the plant, and cannabidiol (CBD) which has been found to provide the most medicinal benefits. Other important compounds include the cannabinoids, CBG and CBN, as well as terpenoids (terpenes) and flavonoids.
It should be noted that the cannabis plant is also composed of compounds that may not be of interest including chlorophyll, fats and waxes.
Tetrahydrocannabinol (THC)
THC is the psychotropic compound in cannabis that produces a “high” in the user. Although it’s commonly associated with the psychoactive high, there are some medicinal benefits found in THC. It may be used to treat nausea, eating disorders, glaucoma, insomnia, pain, and anxiety.
Cannabidiol (CBD)
CBD is non-psychotropic, meaning it doesn’t give the user a “high” and is most commonly associated with the medicinal benefits of cannabis use. Strains of cannabis with a high percentage of CBD can be used to help treat depression, anxiety, seizures, pain and other illnesses. Furthermore, studies have shown that when CBD interacts with certain receptors in the brain it can inhibit THC molecules ability to bind with those receptors, helping reduce any negative effects of THC like anxiety, paranoia or memory-impairment.
Cannabigerol (CBG)
CBG is a non-psychotropic cannabinoid that has recently become more prevalent in the medical research field. Studies have shown it can help reduce inflammation, slow the growth of cancer cells, and combat pain. Common cannabis strains contain a minimal amount of CBG, usually less than 1% by weight. Due to this minimal amount and the difficulty to extract it, CBG is one of the most expensive cannabinoids to produce.
Cannabinol (CBN)
Cannabinol is a cannabinoid resulting from the oxidation and decomposition of the THC molecule over time. It has a mild psychoactive effect, between 10-15% the potency of THC and has the potential to help alleviate insomnia, inflammation and pain while increasing the users’ appetite.
Terpenoids (Terpenes)
Terpenes are fragrant oils found in many different types of plants that give the plant its scent. There are over 100 identified terpenes, most of which are unique to the cannabis plant. The most common terpenes found in cannabis include Myrcene, Pinene, Limonene, Linalool and Beta-Caryophyllene. Terpene profiles can vary drastically between strains, and affect the smell and taste. Research into the therapeutic uses of terpenes is in its early stages, but some believe specific terpenes may have medicinal benefits.
Flavonoids
Flavonoids makeup almost 10% of the compounds in cannabis, but are not unique to the cannabis plant. In fact, more than 6000 flavonoids have been discovered in a variety of plants and food. These compounds are what’s responsible for non-green pigmentation in plants and flowers, and help protect the plant against harmful UV rays, pests, and diseases.
Unfortunately, research into these compounds is still vastly understudied, but some studies have found potential anti-inflammatory, anti-fungal, and anti-oxidant properties associated with specific flavonoids.
Check back next week for Part 3 of the series where we look at the history of cannabis extraction techniques.
