Cannabis sativa is an annual herbaceous plant in the Cannabis genus, a species of the Cannabaceae family. People have cultivated cannabis sativa throughout recorded history as a source of industrial fibre, seed oil, food, recreation, religious and spiritual enlightenment, and medicine. Each part of the plant is harvested differently, depending on the purpose of its use.

Common uses [edit]

A sack made from hemp fiber

Its seeds are chiefly used to make hempseed oil which can be used for cooking, lamps, lacquers, or paints. They are also used as caged-bird feed, for it is a moderate source of nutrients for most birds. The flowers (and to a lesser extent the leaves, stems, and seeds) contain psychoactive and physiologically active chemical compounds known as cannabinoids that are consumed for recreational, medicinal, and spiritual purposes. When so used, preparations of flowers (marijuana) and leaves and preparations derived from resinous extract (hashish) are consumed by smoking, vaporizing and oral ingestion. Historically, tinctures, teas, and ointments have also been common preparations.

Plant physiology [edit]

The flowers of the female plant are arranged in racemes and can produce hundreds of seeds. Male plants shed their pollen and die several weeks prior to seed ripening on the female plants. Although genetic factors dispose a plant to become male or female, environmental factors including the diurnal light cycle can alter sexual expression.^{[citation needed]} Naturally occurring monoecious plants, with both male and female parts, are either sterile or fertile but artificially induced "hermaphrodites" (a commonly used misnomer) can have fully functional reproductive organs. "Feminized" seed sold by many commercial seed suppliers are derived from artificially "hermaphrodytic" females that lack the male gene, or by treating the seeds with hormones or silver thiosulfate.

A Cannabis plant in the vegetative growth phase of its life requires more than 12–13 hours of light per day to stay vegetative. Flowering usually occurs when darkness equals at least 12 hours per day. The flowering cycle can last anywhere between nine to fifteen weeks, depending on the strain and environmental conditions.

In soil, the optimum pH for the plant is 6.3 to 6.8. In hydroponic growing, the nutrient solution is best at 5.2 to 5.8, making Cannabis well-suited to hydroponics because this pH range is hostile to most bacteria and fungi.

• Cultivars primarily cultivated for their fiber, characterized by long stems and little branching.
• Cultivars grown for seed from which hemp oil is extracted.
• Cultivars grown for medicinal or recreational purposes. A nominal if not legal distinction is often made between industrial hemp, with concentrations of psychoactive compounds far too low to be useful for that purpose, and it is also known as marijuana.

Pharmacology [edit]

Δ⁹-tetrahydrocannabinol (THC)

The bud of a hybrid Cannabis sativa indica plant

Cannabis sativa, scientific drawing from c1900

Although the main psychoactive constituent of Cannabis is tetrahydrocannabinol (THC), the plant is known to contain about sixty cannabinoids; however, most of these "minor" cannabinoids are only produced in trace amounts.^{[citation needed]} Besides THC, another cannabinoid produced in high concentrations by some plants is cannabidiol (CBD), which is not psychoactive but has recently been shown to block the effect of THC in the nervous system.^[1] Differences in the chemical composition of Cannabis varieties may produce different effects in humans. Synthetic THC, called dronabinol, does not contain CBD, CBN, or other cannabinoids, which is one reason why its pharmacological effects may differ significantly from those of natural Cannabis preparations.

Yet to be globally proven in standard control surveys, a North American study conducted by think tank Source Watch was the first to analyze the correlations between the smoking of certain sativa strains of cannabis and academic achievement. In particular, sativa plants which were harvested in the two to three month of ostegination led to the stimulation of chords within cerebellum which otherwise remain dead throughout daily activity. In particular, studies on intelligence suggest that daily smokers, being three to five times a week, experienced the stimulation of these chords daily and thus served as the benefactors of the ostegination process which leads to this strain of sativa.

Some therapeutic uses of sativas:^{[2][verification needed]}

• Reduces depression, elevates mood
• Relieves headaches and migraines
• Relieves menstrual cramps
• Energises and stimulates
• Increases focus and creativity
• Reduces nausea
• Stimulates appetite

Chemical constituents [edit]

Cannabis chemical constituents including about 100 compounds responsible for its characteristic aroma. These are mainly volatile terpenes and sesquiterpenes.

• Tetrahydrocannabinol (THC)
• Cannabidiol (CBD)
• α-Pinene^[3]
• Myrcene^[3]
• Trans-β-ocimene^[3]
• α-Terpinolene^[3]
• Trans-caryophyllene^[3]
• α-Humulene,^[3] contributes to the characteristic aroma of Cannabis sativa
• Caryophyllene-oxide,^[3] with which some hashish detection dogs are trained^[4]

See also [edit]

Cannabis portal

References [edit]