Cannabis sativa

Cannabis sativa
Scientific classification
Kingdom: Plantae
(unranked): Angiosperms
(unranked): Eudicots
(unranked): Rosids
Order: Rosales
Family: Cannabaceae
Genus: Cannabis
Species: C. sativa
Binomial name
Cannabis sativa
Linnaeus
Subspecies

C. sativa subsp. sativa
C. sativa subsp. indica

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

Contents

Common uses

A sack made from hemp fiber

Its seed, chiefly used as caged-bird feed, is a valuable source of protein. 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

The bud of a Cannabis sativa plant
Cannabis sativa, scientific drawing from c1900

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

Although the main psychoactive chemical compound in Cannabis is Δ9-tetrahydrocannabinol (THC), the plant is known to contain about sixty cannabinoids; however, most of these "minor" cannabinoids are only produced in trace amounts. 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.

Chemical constituents

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

See also

References

  1. ^ West, D. P, Ph.D. 1998. Hemp and Marijuana: Myths & Realities. North American Industrial Hemp Council. Retrieved on 23 April 2007
  2. ^ a b c d e f g Novak J, Zitterl-Eglseer K, Deans SG, Franz CM (2001). "Essential oils of different cultivars of Cannabis sativa L. and their antimicrobial activity". Flavour and Fragrance Journal 16 (4): 259–262. doi:10.1002/ffj.993. 
  3. ^ Essential Oils

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  • Cannabis sativa — marijuana marijuana n. 1. A strong smelling Asian plant ({Cannabis sativa}), also called {hemp}, from which a number of euphorogenic and halucinogenic drugs are prepared. The euphoric effect is predominently due to {tetrahydrocannabinol} ({THC}) …   The Collaborative International Dictionary of English

  • Cannabis sativa — Hemp Hemp (h[e^]mp), n. [OE. hemp, AS. henep, h[ae]nep; akin to D. hennep, OHG. hanaf, G. hanf, Icel. hampr, Dan. hamp, Sw. hampa, L. cannabis, cannabum, Gr. ka nnabis, ka nnabos; cf. Russ. konoplia, Skr. [,c]a[.n]a; all prob. borrowed from some… …   The Collaborative International Dictionary of English

  • Cannabis sativa — Cannabin Can na*bin, n. (Chem.) A poisonous resin extracted from hemp ({Cannabis sativa}, variety Indica). The euphoric and narcotic effects of hasheesh are due to this resin; the active ingredient is tetrahydrocannabinol, THC. See {Cannabis… …   The Collaborative International Dictionary of English

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