This is an old revision of this page, as edited by 206.176.103.189 (talk) at 21:41, 26 February 2007 (→Taxonomy). The present address (URL) is a permanent link to this revision, which may differ significantly from the current revision.
Revision as of 21:41, 26 February 2007 by 206.176.103.189 (talk) (→Taxonomy)(diff) ← Previous revision | Latest revision (diff) | Newer revision → (diff)| Cannabis | |
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| Scientific classification | |
| Kingdom: | Plantae |
| Division: | Magnoliophyta |
| Class: | Magnoliopsida |
| Order: | Urticales |
| Family: | Cannabaceae |
| Genus: | Cannabis L. |
| Species | |
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Cannabis sativa L. | |
- This article is about the plant genus Cannabis. For use as a psychoactive drug, see Cannabis (drug). For use as a therapeutic drug, see Medical Cannabis. For non-drug cultivation and uses, see Hemp.
Cannabis is a genus of flowering plant that includes one or more species. The plant is believed to be indigenous to Central Asia, China, and the north-west Himalayas. The common name for Cannabis is hemp, although this term is sometimes used to refer only to strains cultivated for "industrial" (non-drug) use. Cannabis plants produce a unique family of compounds called cannabinoids, several of which produce mental and/or physiological effects when consumed. The crude drug usually comes in the form of dried flowers and leaves, resin (hashish), or various extracts. The cultivation or possession of Cannabis for drug purposes is outlawed in most countries.
Species
Putative species:
- C. indica Lam.
- C. ruderalis Janisch.
Description
Cannabis is an annual, dioecious, flowering herb. The leaves are palmately compound, with serrate leaflets. The first pair of leaves usually have a single leaflet, the number gradually increasing up to a maximum of about thirteen leaflets per leaf (usually seven or nine), depending on variety and growing conditions. At the top of a flowering plant, this number again diminishes to a single leaflet per leaf. The lower leaf pairs usually occur in an opposite leaf arrangement and the upper leaf pairs in an alternate arrangement on the main stem of a mature plant.
Cannabis usually has imperfect flowers with staminate "male" and pistillate "female" flowers occuring on separate plants, although hermaphroditic flowers sometimes occur. Male flowers are borne on loose panicles, and female flowers are borne on racemes. It is not unusual for individual plants to bear both male and female flowers in some strains, a condition called monoecy. On monoecious plants, flowers of both sexes may occur on separate inflorescences, or on the same inflorescence.
Cannabinoids, terpenoids, and and other volatile compounds are secreted by glandular trichomes that occur most abundantly on the floral calyxes and bracts of female plants.
All known strains of Cannabis are wind-pollinated and produce "seeds" that are technically called achenes. Most strains of Cannabis are short day plants , with the possible exception of C. sativa subsp. sativa var. spontanea (= C. ruderalis), which is commonly described as "auto-flowering" and may be day-neutral.
Cannabis is naturally diploid, having a chromosome complement of 2n=20, although polyploid individuals have been artificially produced.
Geographical distribution
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Wild cannabis
Wild C. sativa subsp. indica is mainly confined to hash producing areas such as Afghanistan, and parts of Morocco. Wild C. sativa subsp. sativa shows great local variation; for example, in warm places, it can reach heights up to 20 feet (6 m) tall, but in colder climates it can be as short as 1 foot (30 cm) in height. Almost every single flower branch bears a seed. The wild C. sativa subsp. sativa has long, thin and airy buds and a Christmas tree shape structure. Wild C. sativa subsp. indica remains compact and bushy with thick buds for the most part, and is sometimes used by the locals for hashish production. Generally, there are far fewer seeds in wild C. sativa subsp. indica.
In many areas, wild or naturalized populations of Cannabis are considered invasive species, and are often targeted by government-sponsored eradication programmes.
Reproduction
Breeding systems
Cannabis is predominantly dioecious, although many monoecious varieties have been described. Subdioecy (the occurrence of monoecious individuals and dioecious individuals within the same population) is widespread. Many populations have been described as sexually labile.
As a result of intensive selection in cultivation, Cannabis exhibits many sexual phenotypes that can be described in terms of the ratio of female to male flowers occurring in the individual, or typical in the cultivar. Dioecious varieties are preferred for drug production, where the female plants are preferred. Dioecious varieties are also preferred for textile fiber production, whereas monoecious varieties are preferred for pulp and paper production. It has been suggested that the presence of monoecy can be used to differentiate between licit crops of monoecious hemp and illicit dioecious drug crops.
Mechanisms of sex determination
Cannabis has been described as having one of the most complicated mechanisms of sex determination among the dioecious plants. Many models have been proposed to explain sex determination in Cannabis.
Based on studies of sex reversal in hemp, it was first reported by K. Hirata in 1924 that an XY sex-determination system is present. At the time, the XY system was the only known system of sex determination. The X:A system was first described in Drosophila spp in 1925. Soon thereafter, Schaffner disputed Hirata's interpretation, and published results from his own studies of sex reversal in hemp, concluding that an X:A system was in use and that futhermore sex was strongly influenced by environmental conditions.
Since then, many different types of sex determination system have been discovered, particularly in plants. Dioecy is relatively uncommon in the plant kingdom, and a very low percentage of dioecious plant species have been determined to use the XY system. In most cases where the XY system is found it is believed to have evolved recently and independently.
Since the 1920's, a number of sex determination models have been proposed for Cannabis. Ainsworth describes sex determination in the genus as using "an X/autosome dosage-type."
The question of whether heteromorphic sex chromosomes are indeed present is most conveniently answered if such chromosomes were clearly visible in a karyotype. Cannabis was one of the first plant species to be karyotyped, however, this was in a period when karyotype preparation was primitive by modern standards (see History of Cytogenetics). Heteromorphic sex chromosomes were reported to occur in staminate individuals of dioecious 'Kentucky' hemp, but were not found in pistillate individuals of the same variety. Dioecious 'Kentucky' hemp was assumed to use an XY mechanism. Heterosomes were not observed in analyzed individuals of monoecious 'Kentucky' hemp, nor in an unidentified German cultivar. These varieties were assumed to have sex chromosome composition XX. According to other researchers, no modern karyotype of Cannabis had been published as of 1996. Proponents of the XY system state that Y chromosome is slightly larger than the X, but difficult to differentiate cytologically.
More recently, Sakamoto and various co-authors have used RAPD to isolate several genetic marker sequences that they name Male-Associated DNA in Cannabis (MADC), and which they interpret as indirect evidence of a male chromosome. Several other research groups have reported identification of male-associated markers using RAPD and AFLP. Ainsworth commented on these findings, stating that "It is not surprising that male-associated markers are relatively abundant. In dioecious plants where sex chromosomes have not been identified, markers for maleness indicate either the presence of sex chromosomes which have not been distinguished by cytological methods or that the marker is tightly linked to a gene involved in sex determination."
Environmental sex determination is known to occur in a variety of species. Many researchers have suggested that sex in Cannabis is determined or strongly influenced by environmental factors. Ainsworth reviews that treatment with auxin and ethylene have feminizing effects, and that treatment with cytokinins and gibberellins have masculinizing effects. It has been reported that sex can be reversed in Cannabis using chemical treatment.
Aspects of Cannabis production and use
- Medical Cannabis discusses its use as a medication.
- Cannabis (drug) discusses its use as a recreational drug.
- Spiritual use of cannabis discusses sacramental and religious use.
- Hemp discusses its uses as a source of housing, oil, food, fibers, and industrial materials.
- Cannabis (drug) cultivation discusses aspects of cultivation for medicinal and recreational drug purposes
- Legal issues of Cannabis focuses on the law and enforcement aspects of growing, transporting, selling and using cannabis as a drug.
- Health issues and the effects of cannabis discusses the pharmacology, physical, and mental effects of Cannabis when used as drug.
Etymology
The plant name cannabis is of Semitic origin: ; However, the earlier Sumerian language used the word "kanubi", which means 'cane of two (sexes?)'. This is possibly the source for the Semitic usage.
The Biblical Hebrew term qěnēh bośem, literally "reed of balm", probably refers to cannabis according to some etymologists, but is more commonly thought to be lemon grass, calamus, or even sweet cane, due to widespread translation issues. The Hebrew Bible mentions it in Exodus 30:23 where God commands Moses to make a holy oil of myrrh, cinnamon, qěnēh bośem and cassia to anoint the Ark of the Covenant and the Tabernacle (and thus God's Temple in Jerusalem). Notably, this anointing oil is a special herbal formula that functions as a kind of polish and fragrance for the Ark and Tabernacle, and the Bible forbids its manufacture and use to anoint people (Exodus 30:31-33) with the exception of the Aaronic priesthood (Exodus 30:30).
Elsewhere, the Hebrew Bible simply uses "reed" qānēh as the name of a plant in four places whose context seems to mean "reed of balm" as a fragrant resin, Isaiah 43:24, Jeremiah 6:20, Ezekiel 27:19 and Song of Songs 4:14. The Hebrew name "reed of balm" comes from qěnēh (the noun construct form of qāneh) means a "reed" or "cane" and bośem means "balm" or "aromatic" resin. Hebrew may have adapted the name qannabbôs from "reed of balm" qěnēh bośem as a substitute for the ambiguous name "reed".
This Biblical Hebrew term is often mistranslated as "calamus", also called "lemon grass" (Cymbopogon citratus) or "sweet flag" (Acorus calamus), following an ancient misunderstanding in the Greek Septuagint translation. The Hebrew Bible was written across centuries well up to the 5th Century BCE. However, centuries later, by the time the Septuagint was written around the 2nd Century BCE, the archaic Hebrew word qěnēh bośem appears to have already abbreviated into the later Hebrew form qannabbôs, which is attested in Post Biblical Hebrew literature. Thus, the Septuagint did not recognize the Hebrew expression "reed of balm" and mistook it to refer to some unidentified plant. As a dynamic equivalent, the Septuagint rendered it as "calamus" (Greek kalamos), which indeed is a "balmy" (scented) reed. The calamus plant was known in Greek mythology and processed into an aphrodisiac.
Unambiguous Hebrew or Aramaic references to cannabis are rare and obscure. Syriac has qanpa (a loan from kannabis) and tanuma (see the Comprehensive Aramaic Lexicon.) but neither is found in the Peshitta, the Syriac Bible. Late Syriac Ahiqar texts include qanpa as "ropes of hemp" (tunbei de-qanpa). The Hebrew word qanbes, a loan word from kannabis, is used in the Mishnah as hemp in the sense of a constituent of clothing or other items.
The Scythian term cannabis probably derives from a Semitic origin as well. Sara Benetowa of the Institute of Anthropological Sciences in Warsaw is quoted in the Book of Grass as saying:
The astonishing resemblance between the Semitic 'kanbos' and the Scythian 'cannabis' lead me to suppose that the Scythian word was of Semitic origin. These etymological discussions run parallel to arguments drawn from history. The Iranian Scythians were probably related to the Medes, who were neighbors of the Semites and could easily have assimilated the word for hemp. The Semites could also have spread the word during their migrations through Asia Minor.
Likely, the name 'cannabis' was known from the Semitic merchants who sold this commodity throughout the ancient trade routes of Southeast Asia.
Comparing the English word hemp and the Greek word kannabis shows that the word came down from the presumed Proto-Indo-European language. Words like kanapish for "hemp" occur in some Finno-Ugrian languages. It is likely that, soon after agriculture started, hemp as a cultivated plant spread widely, carrying its name with it. Source of Rus. konoplja, Pers. kanab, Lith. kanapes "hemp," and Eng. canvas and hemp.
References
- Erowid. 2006. Cannabis Basics. Retrieved on 25 Feb 2007
- Lebel-Hardenack, S. and S. R. Grant. 1997. Genetics of sex determination in flowering plants. Trends in Plant Science 2(4): 130–136.
- ^ Cristiana Moliterni, V. M., Luigi Cattivelli, P. Ranalli. and Giuseppe Mandolino. 2005. The sexual differentiation of Cannabis sativa L.: A morphological and molecular study. Euphytica 140(1-2): 95-106. Retrieved on 25 Feb 2007
- Bouquet, R. J. 1950. Cannabis. United Nations Office on Drugs and Crime. Retrieved on 23 Feb 2007
- ^ Mignoni, G. 1999. Cannabis as a licit crop: recent developments in Europe. United Nations Office on Drugs and Crime. Retrieved on 5 Oct 2006
- Mahlberg, Paul G. and Eun Soo Kim. 2001. THC (tetrahyrdocannabinol) accumulation in glands of Cannabis (Cannabaceae). The Hemp Report 3(17). Retrieved on 23 Feb 2007
- ^ Clarke, Robert Connell. 1991. Marijuana Botany, 2nd ed. Ronin Publishing, California. ISBN 0-914171-78-X
- Small, E. 1975. Morphological variation of achenes of Cannabis. Canadian Journal of Botany 53(10): 978-987.
- Small, E. 1972. Interfertility and chromosomal uniformity in Cannabis. Canadian Journal of Botany 50(9): 1947-1949.
- ^ Ainsworth, C. 2000. Boys and girls come out to play: the molecular biology of dioecious plants. Annals of Botany 86(2): 211-221. Retrieved on 24 Feb 2007
- de Meijer, E. P. M. 1999. Cannabis germplasm resources. In: Ranalli P. (ed.). Advances in Hemp Research, Haworth Press, Binghamton, NY, pp. 131-151.
- Schumann, E., A. Peil, and W. E. Weber. 1999. Preliminary results of a German field trial with different hemp (Cannabis sativa L.) accessions. Genetic Resources and Crop Evolution 46(4): 399-407. Retrieved on 24 Feb 2007
- Ranalli, Paolo. 2004. Current status and future scenarios of hemp breeding. Euphytica 140(1): 121-131.
- ^ Hirata, K. 1924. Sex reversal in hemp. Journal of the Society of Agriculture and Forestry 16: 145-168.
- ^ Schaffner, J. H. 1931. The fluctuation curve of sex reversal in staminate hemp plants induced by photoperiodicity. American Journal of Botany 18(6): 424-430.
- ^ Cite error: The named reference
mandolino2002awas invoked but never defined (see the help page). - ^ Truta, E., E. Gille, E. Toth, and M. Maniu. 2002. Biochemical differences in Cannabis sativa L. depending on sexual phenotype. Journal of Applied Genetics 43(4): 451-462. Retrieved on 24 Feb 2007
- Bridges, C. B. 1925. Sex in relation to chromosomes and genes. American Naturalist 59: 127-137.
- Schaffner, J. H. 1929. Heredity and sex. Ohio Journal of Science 29(1): 289-300.
- Negrutiu, I., B. Vyskot, N. Barbacar, S. Georgiev, and F. Moneger. 2001. Dioecious plants; a key to the early events of sex chromosome evolution. Plant Physiology 127(4): 418-424.
- Menzel, Margaret Y. 1964. Meiotic chromosomes of monoecious Kentucky hemp (Cannabis sativa). Bulletin of the Torrey Botanical Club 91(3): 193-205.
- Shao Hong and Robert C. Clarke. 1996. Taxonomic studies of Cannabis in China. Journal of the International Hemp Association 3(2): 55-60. Retrieved on 25 Feb 2007
- Peil, A., H. Flachowsky, E. Schumann, and W. E. Weber. 2003. Sex-linked AFLP markers indicate a pseudoautosomal region in hemp (Cannabis sativa L.). Theoretical and Applied Genetics 107(1): 102-109.
- Sakamoto, K., K. Shimomura, Y. Komeda, H. Kamada, and S. Satoh. 1995. A male-associated DNA sequence in a dioecious plant, Cannabis sativa L. Plant & Cell Physiology 36(8): 1549-1554. Retrieved on 25 Feb 2007
- Sakamoto, K., T. Abe, T. Matsuyama, S. Yoshida, N. Ohmido, K. Fukui, and S. Satoh. 2005. RAPD markers encoding retrotransposable elements are linked to the male sex in Cannabis sativa L. Genome 48(5): 931-936. Retrieved on 25 Feb 2007
- Törjék, O., N. Bucherna, E. Kiss, H. Homoki, Z. Finta-Korpelová, I. Bócsa, I. Nagy, and L. E. Heszky. 2002. Novel male specific molecular markers (MADC5, MADC6) for sex identification in hemp. Euphytica 127: 209-218.
- Cite error: The named reference
meijer2003awas invoked but never defined (see the help page). - Tanurdzic, M. and J. A. Banks. 2004. Sex-determining mechanisms in land plants. Plant Cell 16 (suppl.): S61-71.
- Mohan Ram, H. Y., and R. Sett. 1982. Induction of fertile male flowers in genetically female Cannabis sativa plants by silver nitrate and silver thiosulfate anionic complex. Theoretical and Applied Genetics 62: 369-375.
- Weston La Barre. 1980. Culture in Context; Selected Writings of Weston Labarre. Duke University Press. (source not confirmed)
- ^ Benetowa, Sara = (Sula Benet). 1936. Tracing one word through different languages. Institute of Anthropological Sciences, Warsaw. Reprinted 1967 In: The Book of Grass. George Andrews and Simon Vinkenoog (eds.) Grove Press, New York, "pp. 15-18.
- Immanuel Löw. 1924-1934. Flora der Juden, vol. I-IV. Reprinted 1967. Hildeshein: Georg Olms (source not confirmed)
See Also
Further reading
- Cannabis: A History (2005) Martin Booth ISBN 0-312-32220-8
- UNODC: World Drug Report 2006, Chapter 2: Cannabis: Why We Should Care (2006)
External links
- International Plant Names Index (IPNI)
- The Endocannabinoid System Network (ECSN) - Contains medical information to the Endocannabinoid System
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