Camellia sinensis is a species of evergreen shrub or small tree whose leaves and leaf buds are used to produce tea. It is of the genus Camellia (Chinese: 茶花; pinyin: Cháhuā, literally: "tea flower") of flowering plants in the family Theaceae. Common names include "tea plant", "tea shrub", and "tea tree" (not to be confused with Melaleuca alternifolia, the source of tea tree oil, or Leptospermum scoparium, the New Zealand Tea Tree).
|Camellia sinensis foliage|
Camellia sinensis var. sinensis and Camellia sinensis var. assamica, are two major varieties grown today. White tea, yellow tea, green tea, oolong, dark tea (which includes pu-erh tea) and black tea are all harvested from one or the other, but are processed differently to attain varying levels of oxidation. Kukicha (twig tea) is also harvested from Camellia sinensis, but uses twigs and stems rather than leaves.
Nomenclature and taxonomyEdit
Carl Linnaeus chose his name in 1753 for the genus to honor Kamel's contributions to botany (although Kamel did not discover or name this plant, or any Camellia, and Linnaeus did not consider this plant a Camellia but a Thea).
Four varieties of Camellia sinensis are recognized. Of these, C. sinensis var. sinensis and C. sinensis var. assamica (JW Masters) Kitamura are most commonly used for tea, and C. sinensis var. pubilimba Hung T. Chang and C. sinensis var. dehungensis (Hung T. Chang & BH Chen) TL Ming are sometimes used locally.
Camellia sinensis is an evergreen shrub or small tree that is usually trimmed to below 2 m (6.6 ft) when cultivated for its leaves. It has a strong taproot. The flowers are yellow-white, 2.5–4 cm (0.98–1.57 in) in diameter, with 7 to 8 petals.
The seeds of Camellia sinensis and Camellia oleifera can be pressed to yield tea oil, a sweetish seasoning and cooking oil that should not be confused with tea tree oil, an essential oil that is used for medical and cosmetic purposes, and originates from the leaves of a different plant.
The leaves are 4–15 cm (1.6–5.9 in) long and 2–5 cm (0.79–1.97 in) broad. Fresh leaves contain about 4% caffeine, as well as related compounds including theobromine. The young, light-green leaves are preferably harvested for tea production; they have short white hairs on the underside. Older leaves are deeper green. Different leaf ages produce differing tea qualities, since their chemical compositions are different. Usually, the tip (bud) and the first two to three leaves are harvested for processing. This hand picking is repeated every one to two weeks.
Camellia sinensis is mainly cultivated in tropical and subtropical climates, in areas with at least 127 cm (50 inches) of rainfall a year. Tea plants prefer a rich and moist growing location in full to part sun, and can be grown in hardiness zones 7 – 9. However, the clonal one is commercially cultivated from the equator to as far north as Cornwall and Scotland on the UK mainland. Many high quality teas are grown at high elevations, up to 1,500 meters (4,900 feet), as the plants grow more slowly and acquire more flavour.
Tea plants will grow into a tree if left undisturbed, but cultivated plants are pruned to waist height for ease of plucking. Two principal varieties are used, the small-leaved Chinese variety plant (C. sinensis sinensis) and the large-leaved Assamese plant (C. sinensis assamica), used mainly for black tea.
The Chinese plant (sometimes called C. sinensis var. sinensis) is a small-leafed bush with multiple stems that reaches a height of some 3 meters. It is native to southeast China. The first tea plant to be discovered, recorded and used to produce tea dates back 3,000 years ago, it yields some of the most popular teas.
C. sinensis var. waldenae was considered a different species, Camellia waldenae by SY Hu, but it was later identified as a variety of C. sinensis. This variety is commonly called Waldenae Camellia. It is seen on Sunset Peak and Tai Mo Shan in Hong Kong. It is also distributed in Guangxi province, China.
Indian and Nepali teasEdit
Three main kinds of tea are produced in India:
- Assam comes from the heavily forested northeastern section of the country, Assam. Tea from here is rich and full-bodied. It was in Assam that the first tea estate of India was established, in 1837.
- Darjeeling, from the cool and wet Darjeeling region, tucked in the foothills of the Himalayas. Tea plantations reach 2,200 metres. The tea is delicately flavoured, and considered to be one of the finest teas in the world. The Darjeeling plantations have 3 distinct harvests, termed 'flushes', and the tea produced from each flush has a unique flavour. First (spring) flush teas are light and aromatic, while the second (summer) flush produces tea with a bit more bite. The third, or autumn flush gives a tea that is lesser in quality.
Nepali tea is also considered to be similar to the tea produced in Darjeeling, mostly because the eastern part of Nepal, where a large amount of tea is produced, has similar topography to that of Darjeeling.
- Nilgiri, from a southern region of India almost as high as Darjeeling. Grown at elevations between 1,000 and 2,500 metres, Nilgiri teas are subtle and rather gentle, and are frequently blended with other, more robust teas.
Pests and diseasesEdit
Although health benefits have been assumed throughout the history of using Camellia sinensis as a common beverage, there is no high-quality evidence that tea confers significant benefits. In clinical research over the early 21st century, tea has been studied extensively for its potential to lower the risk of human diseases, but none of this research is conclusive as of 2017.
Biosynthesis of caffeineEdit
Caffeine is a molecule produced in Camellia sinensis which functions as a secondary metabolite. Caffeine is a purine alkaloid and its biosynthesis occurs in young tea leaves and is regulated by several enzymes. The biosynthetic pathway in C. sinensis differs from other caffeine producing plants such as coffee or guayusa. Analysis of the pathway was carried out by harvesting young leaves and using reverse transcription PCR to analyze the genes encoding the major enzymes involved in synthesizing caffeine. The gene TCS1 encodes caffeine synthase. Younger leaves feature high concentrations of TCS1 transcripts, allowing more caffeine to be synthesized during this time. Dephosphorylation of xanthosine-5'-monophosphate into xanthosine is the committed step for the xanthosines entering the beginning of the most common pathway. A sequence of reactions turns xanthosine into 7-methylxanthosine, then 7-methylxanthine, then theobromine, and finally into caffeine.
- Chinese herbology
- Green tea extract
- International Code of Nomenclature for Cultivated Plants
- ISO 3103, a method of brewing tea according to the ISO
- Kaempferol, a flavanoid found in tea and associated with reduced risk of heart disease
- List of tea companies
- Tasseography, a method of divination by reading tea leaves.
- Tea classics
- Tea production in Sri Lanka
- Turkish tea
- Tea production in Kenya
- Nepali tea
- Tea leaf grading
- Camellia taliensis
Primary green tea catechinsEdit
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Georg Jeoseph Kamel, whose name in Latin was Camellus was missionary to the Philippines, died in Manilla in 1706. […] Camellias were named in posthumous honor of George Joseph Kamel by Carolus Linnæus.
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It is speculated that he never saw a camellia.
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The first edition of Linnaeus's Species Plantarum published in 1753 suggested calling the tea plant Thea sinensis...
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The generic names Thea L. (Sp. Pl.: 515. 24 Mai 1753), and Camellia L. (Sp. Pl.: 698. 16 August 1753; Gen. Pl., ed. 5: 311. 1754), are treated as having been published simultaneously on 1 May 1753. … the combined genus bears the name Camellia, since Sweet (Hort. Suburb. Lond.: 157. 1818), who was the first to unite the two genera, chose that name, and cited Thea as a synonym.
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|Wikimedia Commons has media related to Camellia sinensis.|
|Wikispecies has information related to Camellia sinensis|
- "Camellia sinensis". Integrated Taxonomic Information System. Retrieved 16 February 2006.
- Camellia sinensis from Purdue University
- The International Camellia Society
- Plant Cultures: botany and history of the tea plant
- Antibacterial Activity of Green Tea Extracts against Streptococcus anginosus group CI.NII.AC.jp
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