Cannabis sativa is an annual Herbaceous plant flowering plant. The species was first classified by Carl Linnaeus in 1753.[Greg Green, The Cannabis Breeder's Bible, Green Candy Press, 2005, pp. 15-16 ] The specific epithet Sativum means 'cultivated'. Indigenous to East Asia, the plant is now of cosmopolitan distribution due to widespread cultivation.
Description
The flowers of
Cannabis sativa plants are most often either male or female, but only plants displaying female pistils can be or turn hermaphrodite. Males can never become hermaphrodites.
It is a short-day flowering plant, with staminate (male) plants usually taller and less robust than pistillate (female or male) plants.
The
of the female plant are arranged in
and can produce hundreds of seeds. Male plants shed their pollen and die several weeks prior to seed ripening on the female plants. Under typical conditions with a light period of 12 to 14 hours, both sexes are produced in equal numbers because of heritable X and Y chromosomes.
Although genetic factors dispose a plant to become male or female, environmental factors including the
Diurnal cycle can alter sexual expression.
Naturally occurring
monoecious plants, with both male and female parts, are either sterile or fertile; but artificially induced "
hermaphrodites" can have fully functional reproductive organs.
"Feminized" seed sold by many commercial seed suppliers
are derived from artificially "hermaphroditic" females that lack the male gene, or by treating the plants with hormones or silver
thiosulfate.
Chemical constituents
Although the main
psychoactive constituent of
Cannabis is tetrahydrocannabinol (THC), the plant is known to contain more than 500 compounds, among them at least 113
; 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.
Differences in the chemical composition of
Cannabis varieties may produce different effects in humans. Synthetic THC, called
dronabinol, does not contain cannabidiol (CBD),
cannabinol (CBN), or other cannabinoids, which is one reason why its
Pharmacology effects may differ significantly from those of natural
Cannabis preparations.
Beside cannabinoids, the chemical constituents of Cannabis include about 120 compounds responsible for its characteristic aroma. These are mainly volatile and .
A 1980 study identifying constituents of C. sativa
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(18)
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(6)
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(12)
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(18)
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(55)
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(11)
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(14)
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(20)
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(46)
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(13)
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(18)
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(14)
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(111)
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(2)
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(7)
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(9)
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(32)
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(98)
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(1)
Cannabis also produces numerous volatile sulfur compounds that contribute to the plant's skunk-like aroma, with prenylthiol (3-methyl-2-butene-1-thiol) identified as the primary odorant.
A number of specific aromatic compounds have been implicated in variety-specific aromas.
In addition to volatile sulfur compounds, the heterocyclic compounds indole and skatole (3-Methyl-1 H-indole) contribute to the chemical or savory aromas of certain varieties.
Cultivation
A
Cannabis plant in the vegetative growth phase requires more than 16–18 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 seven and fifteen weeks, depending on the strain and environmental conditions. When the production of psychoactive
cannabinoids is sought, female plants are grown separately from male plants to induce
parthenocarpy in the female plant's fruits (popularly called "sin semilla" which is Spanish for "without seed" ) and increase the production of
cannabinoid-rich resin.
In soil, the optimum pH for the plant is 6.3 to 6.8. In hydroponics 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.
Tissue culture multiplication has become important in producing medically important clones,
Cultivars
Broadly, there are three main
cultivar of cannabis that are cultivated today:
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Cultivars primarily cultivated for their fibre, characterized by long stems and little branching.
-
Cultivars grown for seed which can be eaten entirely raw or from which hemp oil is extracted.
-
Cultivars grown for medicinal or recreational purposes, characterized by extensive branching to maximize the number of flowers.
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 marijuana.
Uses
Cannabis sativa seeds are chiefly used to make hempseed oil which can be used for cooking, lamps, lacquers, or paints. They can also be used as caged-bird feed, as they provide a source of nutrients for most animals. The flowers and fruits (and to a lesser extent the leaves, stems, and seeds) contain
psychoactive chemical compounds known as
cannabinoids that are consumed for recreational, medicinal, and spiritual purposes. When so used, preparations of flowers and fruits (called
marijuana) and leaves and preparations derived from resinous extract (e.g.,
hashish) are consumed by smoking, vaporising, and oral ingestion. Historically,
,
Herbal tea, and
have also been common preparations. In traditional medicine of India in particular
cannabis sativa has been used as hallucinogenic, hypnotic,
sedative,
analgesic, and anti-inflammatory agent.
Terpenes have gained public awareness through the growth and education of medical and recreational cannabis. Organizations and companies operating in cannabis markets have pushed education and marketing of terpenes in their products as a way to differentiate taste and effects of cannabis.
The
entourage effect, which describes the synergy of cannabinoids, terpenes, and other plant compounds, has also helped further awareness and demand for terpenes in cannabis products.
See also
External links
