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Theaceae

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Theaceae
Camellia-1.png
Scientific Classification
Genera
  • Apterosperma
  • Camellia
  • Cleyera
  • Eurya
  • Fraklinia
  • Gordonia
  • Laplacea
  • Polyspora
  • Pyrenaria
  • Schima
  • Stewartia
  • Ternstroemites
  • Tutcheria [2]
Schima brevifolia-8.png
Schima brevifolia

Theaceae is a family of flowering plants comprised of shrubs and trees spread throughout thirteen genera. Most species are evergreen and perennial, and all are hermaphrodite and reproduce by pollination. The leaves of the plants are green, although the exact color and texture varies between genera and species. Although white is one of the most common flower colors, the various genera can have pink, red, and yellow-green petals, with some species bearing fragrance. While originally native to Asia, members of the Theaceae family are now cultivated throughout the world. Many are commercially grown as ornamental plants. The most famous species of the family is C. sinensis, commonly known as the tea plant. Tea is the most important non-alcoholic beverage in the world, with over 3 million tons grown annually. [3] It is not only a widely accepted beverage, it also is used in numerous food and nonfood products; studies show that the plant and brew also have many health benefits. While the value of tea is unquestionable, the mystery remains of how such distinct flavors and qualities can originate from one plant. [4]

Body Design

Camellia japonica. This picture shows the flower's petal arrangement and numerous stamen.

Plants in the family Theaceae, otherwise known as the tea family, can either be shrubs or trees. Most species are evergreen; they keep their green leaves throughout the year. Some, however, turn red before falling off of the plant. [5] The thick leaves of the plant are pinnately veined [6] and bright green, with an often shiny appearance. [3] [5] The leaves are simple (meaning there is only one blade on one petiole) and alternate (the leaves alternate positions on the stem, two leaves do not exist opposite each other). [7] Specific characteristics of leaves can vary slightly between species, such as the hairy underside of C. sinensis and the oval shape of C. japonica. C. reticulata, the largest flowering plant of the Camellia genus, has dull green leaves. [3] [8] [9]

Another characteristic that varies between genera and species is height. For example, the tea plant, C. sinenis, has the potential to grow to 17 meters. However, for cultivating purposes, it is kept below a height of 2 meters through pruning. [3] The common camellia, C. japonica, grows to 9 meters, with 10 cm long leaves. One trait all members of the family Theaceae do share is their strong taproots. [10]

The family Theaceae is known for its showy, and in the case of Camellia genus, fragrant flowers. Several ornamental plants are included in the family. [5] In general, the flowers of members of Theaceae have five sepals (leaf-like structures) and petals. Numerous stamen are inserted at the ovary's base. [11] Like the plants' leaves, however, this characteristic differs between species. The flowers of C. sinensis are scented, and can occur singly or in clusters of two or four. [3] The flowers themselves are about 4 cm wide. The common camellia, C. japonica, has many petals that overlap, their colors ranging from white to pink to red. C. reticulata has the largest flower in the Camellia genus with a maximum width of 15 cm. [8] A variety of color is also seen throughout the species. Members of the genera Franklina, Gordonia, and Stewartia bear white flowers, with purple or yellow-orange stamens. Plants belonging to the genus Eurya have small yellow-green blooms. [11] The famous C. sinensis species possess white flowers and yellow stamens. [3]

The fruit of the Theaceae family can be fleshy or non-fleshy. The fruit is usually a brownish-greenish color, in the shape of a capsule, berry, or drupe. Within these structures lie one to four spherical or flattened seeds; some possess apical wings. They are about 0.4-2 cm long. Hair can also be present on the seeds, which are usually non-endospermic--meaning they do not have a structure that serves as a food storage for the developing embryo. [6] [3] [5]

Life Cycle

The life cycle of the Theaceae family is perennial, with most of the plants being evergreen. [12] The plant is hermaphrodite, meaning it has both male and female organs. [6] However, the plant itself is not very self-compatible. Any flowers that are self-fertilized produce few seeds with low viability. [13] Therefore, it requires cross-pollination by insects, such as bees and moths, to produce flowers and seeds. [10] The ovary of the plant is superior, meaning it is located above the point where the other floral parts are connected to each other. [7] Once pollinated, the plant will flower from autumn to early winter [14] The ovary will later mature into a fruit, in the shape of capsule that eventually splits open. [15] The seeds within the capsule contain two large cotyledons, or embryonic leaves. [6] They usually germinate after 1-3 months at a temperature of 23 degrees Celsius, in the sunlight. [13] [16]

The members of Family Theaceae are slow growing. [3] For example, the tea plant, C. sinensis, takes 4-12 years to produce seed. [10] Maturity is evident when the plant produces tea leaves, consisting of 2 leaves and a bud. These tea leaves grow from the stems of the plant stalks. When they are young, they possess white silky hairs that eventually disappear when the leaf becomes mature. [4] The tea plants grown in China undergo dormancy during the winter, where it stores energy and nutrients until spring. [17] The tea plant also possesses a long lifespan, with the ability to live up to 100 years. Other species also exhibit longevity. C. Assamica has been known to live for 50 years, while C. sinensis plants grown in Taiwan have lifespans of 15-20 years. [4] [18]

Ecology

Point Map of Camellia sinensis, showing how the plant can adapt to various environments.

The Theaceae family is native to Asia. [4] Scientists hypothesize that one of the places it was originally indigenous to is western Yunnan, a province in China. [3] In fact, the name of the most famous species in the Theaceae family, C. sinensis, is the Latin translation of "China". However, the exact origin of this particular species is unknown. [4] Other species of Theaceae are native to Southeast Asia, including Sri Lanka, the Assam region in India, Burma, Thailand, Laos, Cambodia, and Vietnam. [10] [3] Theaceae is also known for being cultivated in the Neotropical zone, a zoographical region of the world that extends from Central Mexico to the very tip of South America. [5] [19] However, plants of the family Theaceae are now cultivated throughout the world, as they are planted widely in tropical, subtropical, and even marine climates. There have even been successful plantations in the southeastern United States. Within these various regions, the plants are grown in differentiating climates; they range from warm temperate dry, to wet, to tropical dry, to moist forest. When near the equator, the plant can grow up to nearly 2000 meters in elevation. This contrasts with the species in India, as in that area most of the plants grow at or just above sea level, rising no higher than 150-200 feet. [10] [4]

The desirable environment for the Theaceae family are as follows: an annual rainfall of 120 cm or more, a humid, warm, climate, and an average temperature that does not fall below 13 degrees Celsius or rise above 30 degrees Celsius. [10] The plant prefers wet summers and cool, dry winters. [13] Other beneficial characteristics of the environment include a loamy soil, meaning one that contains clay and sand with humus. [4] It thrives best in tropical red earths and deep, well-drained soils with a pH levels of 4.5-6.0. [10] An example of an ideal environment would be the foothills of the Himalayas, with its cool temperatures and frequent rain that produce a fertile ground. [4] However, the tea family is very adaptable to its surroundings. [4] It has been reported to tolerate drought, certain levels of frost, low pH levels, peat, shade, and slope. Some specific reports state that C. sinensis has withstood an annual precipitation of 7-31 decimeters, an annual temperature of 14-27 degrees Celsius, and a pH level of 4.5-7.3. [10] The annual precipitation may not appear to be that significant of a drought, but it must be taken into consideration that the tea plant usually requires a considerable amount of water. [4] Two situations that the plant cannot stand, however, are a high level of frost and several months with less than 5 cm of rainfall. [10]

The fragrance of the tea plant is very attractive to insects, especially moths. [13] This attraction can be beneficial since the plant reproduces by pollination. [6] However, several organisms are also harmful, such as numerous fungi, bacteria, and nematodes that are known for attacking the tea plant. [10]

The History, Production, and Uses of Tea

A tea farm in India, of the species C. sinensis.

Although the exact origin of tea is unknown, the legend goes that the mythical Chinese emperor Shen Nung was tired from work one day and made a fire below a tree to heat water. Some leaves from the tree fell into the pot he was heating, and he tasted the water. He felt more awake and refreshed, and promptly drank the pot to the bottom. The emperor realized the herb's usefulness and decided to research the plant. He gave the brew the name "ch'a", the Chinese word for "to check or investigate". It has been thought that this is symbolic of how tea could help bring balance to humanity. [14] While the credibility of this tale can be questioned, the medicinal uses of tea in China have been dated almost 5000 years. Tea has also played a large role in the culture of certain countries, evident by the Japanese tea ceremony and British teatime. [3]

There are three main methods of processing the leaves of C. sinensis to produce tea, but they all start similarly. Fresh leaves are picked from the new growth of the plant; the highest quality crop can be obtained just after the plant's period of dormancy, as it has been concluded that leaves with slow development will produce better flavors. [10] Then, the leaves are bruised and wilted in sunlight or warm air. Finally, they are rolled, twisted, and bruised again. At this point, firing, or heating the leaves would result in green tea. If the leaves were allowed to ferment for a long time before being rolled and twisted, they would become black because of oxidation. This not only darkens the leaves' color but also brings out new flavor compounds, known as tannins. Firing at this point stops the process and produces black tea. The last main method consists of only partially fermenting the leaves, so that there are still flavors of the fresh green tea yet some of the black tea. This results in oolong tea. [14] Along with these types of teas, C. sinensis also produces white and puer, or bolay, tea. [4] Another species, C. Assamica, is used for the production of Indian tea. [3] The numerous other flavors seen on the market are a result of blending teas, mostly with black tea. [14]

For thousands of years, tea has been used as a folk medicine in China. [10] Today, tea is recognized as a beverage and plant with several health benefits. Tea is a stimulant; these effects are caused by xanthines, such as caffeine. While too much intake of caffeine can cause headaches and anxiety, when taken in the right proportions tea serves to be a therapeudic drink. [3] Tea contains two important minerals to the human body, manganese and potassium. Manganese is responsible for bone growth and body development, and potassium keeps the heart beating and maintains body fluid levels. Antioxidants, which are known to help prevent many common human ailments, are also present in tea. Studies also show that tea may help prevent tooth decay; may help fight cancer in the pancreas, prostate, colon, esophagus and mouth; combat heart disease; reduce risks of stroke; reduce blood cholesterol and blood clotting; and lower blood pressure. [14]

Besides its health benefits, tea is also produced and consumed worldwide merely as a commercial beverage. The extract can be found in numerous food products, and the oils of the plant are also used in perfume and food flavoring. [13]

Video

A video with general information about green tea, as well as its health benefits.

Gallery

References

  1. Classification for Kingdom Plantae Down to Family Theaceae USDA. Web. 12 May 2013 (Date-Acessed).
  2. Theaceae Wikispecies. Web. 29 September 2012 (Date-Published).
  3. 3.00 3.01 3.02 3.03 3.04 3.05 3.06 3.07 3.08 3.09 3.10 3.11 3.12 Cammelia Sinensis Kew: Royal Botanic Gardens. Web. 14 May 2013 (Date-Accessed).
  4. 4.00 4.01 4.02 4.03 4.04 4.05 4.06 4.07 4.08 4.09 4.10 Tea Tips Mighty Leaf Tea. Web. 14 May 2013 (Date-Accessed).
  5. 5.0 5.1 5.2 5.3 5.4 Every, Jon. Neotropical Theaceae Kew: Royal Botanic Gardens. Web. 2009 (Date-Published).
  6. 6.0 6.1 6.2 6.3 6.4 Watson, L., and Dallwitz, M. The families of flowering plants DELTA: Description Language for Taxonomy. Web. 19 December 2012 (Date-Published).
  7. 7.0 7.1 Description eol: Encyclopedia of Life. Web. 28 February 2013 (Date-Published).
  8. 8.0 8.1 Camellia Encyclopaedia Britannica. Web. 14 May 2013 (Date-Accessed).
  9. Camelia reiculata Burke's Backyard. Web. 14 May 2013 (Date-Accessed).
  10. 10.00 10.01 10.02 10.03 10.04 10.05 10.06 10.07 10.08 10.09 10.10 10.11 Camellia sinensis NewCROP. Web. 3 July 1996 (Date-Published).
  11. 11.0 11.1 Theaceae Encyclopaedia Britannica. Web. 14 May 2013 (Date-Accessed).
  12. Browse items starting with C Chiltern Seeds. Web. 27 May 2013 (Date-Accessed).
  13. 13.0 13.1 13.2 13.3 13.4 Kuntze, L. Camellia sinensis Plants for a Future. Web. 15 May 2013 (Date-Accessed).
  14. 14.0 14.1 14.2 14.3 14.4 Odom, Debbie. Camellia Sinensis: The Tea Plant Later American Camellias. Web. 27 May 2013 (Date-Accessed).
  15. Theaceae XTBG-Botany. Web. 27 May 2013 (Date-Accessed).
  16. Camellia sinensis Family Powershow.com. Web. 15 April 2013 (Date-Published).
  17. Camellia sinensis TeaClass. Web. 27 May 2013 (Date-Accessed).
  18. Oolong Tea CaryTown Teas. Web. 27 May 2013 (Date-Accessed).
  19. The Neotropical Zone Chipper Woods Bird Observatory. Web. 15 May 2013 (Date-Accessed).