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Populus Trichocarpa Classification Essay

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Description

Populus trichocarpa

Populus trichocarpa

Populus trichocarpa (black cottonwood ; also known as western balsam poplar or California poplar ), is a deciduous broadleaf tree species native to western North America. It is used for timber. and is notable as a model organism in plant biology. Its full genome sequence was published in 2006. It is the first tree species to be sequenced.

Description

It is a large tree, growing to a height of 30 metres (98 ft) to 50 metres (160 ft) and a trunk diameter of over 2 metres (6.6 ft), which makes it the largest poplar species in the Americas. It is normally fairly short-lived, but some trees may live for up to 400 years (Forbes 2006). A cottonwood discovered in Haines, Alaska set the national record at 101 ft (31 m) tall and 32.5 ft (9.9 m) around. [ 1 ]

The bark is grey and covered with lenticels. becoming thick and deeply fissured on old trees. The bark can become hard enough to cause sparks when cut with a chainsaw. [ 1 ] The stem is grey in the older parts and light brown in younger parts. The crown is usually roughly conical and quite dense. In large trees the lower branches droop downwards. Spur shoots are common. The wood has a light coloring and a straight grain.

The leaves are 7–20 cm long with a glossy dark green upper side and glaucous light grey-green underside; larger leaves, up to 30 cm long, may be produced on stump sprouts and very vigorous young trees. The leaves are alternate, elliptic with a crenate margin and an acute tip, and reticulate venation (see leaf terminology ). The petiole is reddish. The buds are conical, long, narrow and sticky, with a strong balsam scent in spring when they open.

P. trichocarpa has an extensive and aggressive root system, which can invade and damage drainage systems. Sometimes the roots can even damage the foundations of buildings by drying out the soil.

Reproduction

Flowering and fruiting

Male (pollen-producing) catkin and leaf buds (March 22)Sherwood. Oregon, USA

P. trichocarpa is normally dioecious ; male and female catkins are borne on separate trees. The species reaches flowering age at about 10 years. Flowers may appear in early March to late May in Washington and Oregon. and sometimes as late as mid-June in northern and interior British Columbia. Idaho. and Montana. Staminate catkins contain 30 to 60 stamens. elongate to 2 to 3 cm, and are deciduous. Pistillate catkins at maturity are 8 to 20 cm long with rotund-ovate. three carpellate subsessile fruits 5 to 8 mm long. Each capsule contains many minute seeds with long, white cottony hairs.

Seed production and dissemination

The seed ripens and is disseminated by late May to late June in Oregon and Washington. but frequently not until mid-July in Idaho and Montana. Abundant seed crops are usually produced every year. Attached to its cotton, the seed is light and buoyant and can be transported long distances by wind and water. Although highly viable, longevity of P. trichocarpa seed under natural conditions may be as short as two weeks to a month. This can be increased with cold storage.

Seeds and Fluff of Cottonwood (July 1, 2012) Boise. Idaho, USA

Moist seedbeds are essential for high germination, and seedling survival depends on continuously favorable conditions during the first month. Wet bottom lands of rivers and major streams frequently provide such conditions, particularly where bare soil has been exposed or new soil laid down. Germination is epigeal. P. trichocarpa seedlings do not usually become established in abundance after logging unless special measures are taken to prepare the bare, moist seedbeds required for initial establishment. Where seedlings become established in great numbers, they thin out naturally by age five because the weaker seedlings of this shade-intolerant species are suppressed.

Due to its high levels of rooting hormones, P. trichocarpa sprouts readily. After logging operations, it sometimes regenerates naturally from rooting of partially buried fragments of branches or from stumps. Sprouting from roots also occurs. The species also has the ability to abscise shoots complete with green leaves. These shoots drop to the ground and may root where they fall or may be dispersed by water transport. In some situations, abscission may be one means of colonizing exposed sandbars .

Distribution

A large specimen in Diamond Ridge, Alaska. and a close-up of the bark at the base of the trunk

The native range of P. trichocarpa covers large sections of western North America. It extends northeast from Kodiak Island along Cook Inlet to latitude 62° 30° N. then southeast in southeast Alaska and British Columbia to the forested areas of Washington and Oregon. to the mountains in southern California and northern Baja California (lat. 31° N.). It is also found inland, generally on the west side of the Rocky Mountains. in British Columbia. western Alberta. western Montana. and northern Idaho. Scattered small populations have been noted in southeastern Alberta. eastern Montana. western North Dakota. western Wyoming. Utah. and Nevada. It grows up to elevations of 2100 m.

Populus trichocarpa has been one of the most successful introduction of trees to the otherwise more or less treeless Faroe Islands .

The species was imported from Alaska to Iceland in 1944 and has since become one of the most widespread trees in the country.

Cultivation

It is also grown as an ornamental tree. valued for its fast growth and scented foliage in spring, detectable from over 100 m distance. The roots are however invasive, and it can damage the foundations of buildings on shrinkable clay soils if planted nearby (Mitchel 1996).

Branches can be added to potted plants to stimulate rooting. [ 1 ]

Use as a model species

P. trichocarpa has several qualities which makes it a good model species for trees:

  • Model genome size (although significantly larger than the other model plant, Arabidopsis thaliana )
  • Rapid growth (for a tree)
  • Reaches reproductive maturity 4–6 years
  • Economically important
  • It represents a phenotypically diverse genus

For these reasons the species has been extensively studied. Its genome sequence was published in 2006 (see "Genome" below). More than 121 000 expressed sequence tags (ESTs) have been sequenced from it. The wide range of topics studied by using P. trichocarpa include the effects of ethylene. lignin biosynthesis. drought tolerance and wood formation.

P. trichocarpa wood is light-weight and although not particularly strong, is strong for its weight. The wood material has short, fine cellulose fibres which are used in the production of high-quality book and magazine paper. The wood is also excellent for production of plywood. Living trees are used as windbreaks .

P. trichocarpa grows very quickly; trees in plantations in Great Britain have reached 18 m (59 ft) tall in 11 years, and 34 m (112 ft) tall in 28 years (Mitchell 1996). It can reach suitable size for pulp production in 10–15 years and about 25 years for timber production.

Native American tribes in the Pacific Northwest used P. trichocarpa for a variety of purposes. The inner bark was sometimes eaten but most of its uses were medicinal or practical. Because of its salicin content it was often used raw or in salves to treat a number of ailments including baldness, tuberculosis, rheumatism, and treating wounds. The wood, roots and bark were used for firewood, canoe making, rope, fish traps, baskets and structures. The gum-like sap was even used as a glue or as waterproofing. [ 2 ]

Commercial extracts are produced from the fragrant buds for use as a perfume in medicines and cosmetics. [ 1 ]

Characteristics General information

The sequence of P. trichocarpa is that of an individual female specimen "Nisqually-1". named after the Nisqually River in the Washington state in the USA. where the specimen was collected. The sequencing was performed at the Joint Genome Institute by using the shotgun method. The depth of the sequencing was approximately 7.5 x (meaning that each base pair was sequenced on average 7.5 times). Genome annotation was done primarily by the Joint Genome Institute. the Oak Ridge National Laboratory. the Umeå Plant Science Centre and Genome Canada.

Prior to the publication of P. trichocarpa genome the only available plant genomes were those of thale cress and rice. both of which are herbaceous. P. trichocarpa is the first woody plant genome to be sequenced. Considering the economic importance of wood and wood products, the availability of a tree genome was necessary. The sequence also allows evolutionary comparisons and the elucidation of basic molecular differences between herbaceous and woody plants.

Somatic mosaicism

Genome-wide analysis of 11 clumps of P. trichocarpa trees reveals significant genetic differences between the roots and the leaves and branches of the same tree. The variation within a specimen is as much as found between unrelated trees. [ 3 ] These results may be important in resolving debate in evolutionary biology regarding somatic mutation (that evolution can occur within individuals, not solely among populations), with a variety of implications. [ 4 ]

Nomenclature

"Trichocarpa" is Greek for "hairy fruits". The following scientific names are now considered synonymous with Populus trichocarpa :

Other articles

Populus trichocarpa

Date: 20 September 2014

Populus trichocarpa
  • Quanzi Li Affiliated with State Key Laboratory of Tree Genetics and Breeding, Chinese Academy of Forestry College of Forestry, Shandong Agricultural University
  • . Ting-Feng Yeh Affiliated with School of Forestry and Resource Conservation, National Taiwan University
  • . Chenmin Yang Affiliated with State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University
  • . Jingyuan Song Affiliated with Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences, Peking Union Medical College
  • . Zenn-Zong Chen Affiliated with Division of Silviculture, Taiwan Forestry Research Institute
  • . Ronald R. Sederoff Affiliated with State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University
  • . Vincent L. Chiang Affiliated with State Key Laboratory of Tree Genetics and Breeding, Chinese Academy of Forestry College of Forestry, Shandong Agricultural University Email author

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Populus trichocarpa Nisqually-1 is a clone of black cottonwood that is widely used as a model woody plant. It was the first woody plant to have a full genome sequence and remains today as the model for growth, metabolism, development, and adaptation for all woody dicotyledonous plants. It is one of the best-annotated plant genomes available. It is also currently studied to improve bioenergy feedstocks and to learn about responses to environmental variation that may result from climate change. It is the best characterized woody plant for lignin biosynthesis. In spite of its role as a model woody plant, many important genetic applications have been limited because it was particularly difficult for DNA transformation. The ability to transform P. trichocarpa is a central component of a systems biology approach to the study of metabolic and developmental processes, where in combination with genome and transcriptome sequencing, all the expressed genes for specific pathways can be defined, cloned, and characterized for biological function.

We previously reported on a method for Agrobacterium -mediated genetic transformation in P. trichocarpa (Song et al. Plant Cell Physiol 47: 1582–1589, 2006). Since then, we have optimized the protocol based on many experiments that varied in tissue manipulation, media, DNA constructs and Agrobacterium strains. A modified step-by-step protocol for Agrobacterium -mediated transformation of stem explants is described here. The health of the tissue explants and the time of cocultivation are among the critical steps in the protocol for successful transformation. This updated protocol should be helpful to many laboratories that are currently carrying out P. trichocarpa transformation. It should also encourage many labs that have not yet had success with P. trichocarpa to try again.

Agrobacterium tumefaciens Genetic transformation Populus trichocarpa Transgenic trees

Populus trichocarpa

Populus trichocarpa

Populus trichocarpa (Black Cottonwood ; also known as Western Balsam Poplar or California Poplar ) is a tree species native to western North America. It is used for timber. and is notable as a model organism in plant biology. Its full genome sequence was published in 2006. It contains the largest number of genes ever discovered in any organism.

[edit ] Description

It is a large tree, growing to a height of 30-50 m and a trunk diameter of over 2 m, which makes it the largest poplar species in the Americas. The bark is grey and covered with lenticels. becoming thick and deeply fissured on old trees. It is normally fairly short-lived, but some trees may live for up to 400 years (Forbes 2006).

The stem is grey in the older parts and light brown in younger parts. The crown is usually roughly conical and quite dense. In large trees the lower branches droop downwards. Spur shoots are common. The wood is has light color and straight grain.

The leaves are 7-20 cm long with a dark green upper side and glaucous light grey-green underside; larger leaves, up to 30 cm long, may be produced on stump sprouts and very vigorous young trees. The leaves are alternate, elliptic with a crenate margin and an acute tip, and reticulate venation (see leaf terminology ). The petiole is reddish. The buds are conical, long, narrow and sticky, with a strong balsam scent in spring when they open.

P. trichocarpa has an extensive and aggressive root system, which can invade and damage drainage systems. Sometimes the roots can even damage the foundations of buildings by drying out the soil.

[edit ] Reproduction

Flowering and Fruiting

P. trichocarpa is normally dioecious ; male and female catkins are borne on separate trees. The species reaches flowering age at about 10 years. Flowers may appear in early March to late May in [Washington] and Oregon. and sometimes as late as mid-June in northern and interior British Columbia. Idaho. and Montana. Staminate catkins contain 30 to 60 stamens. elongate to 2 to 3 cm, and are deciduous. Pistillate catkins at maturity are 8 to 20 cm long with rotund-ovate. three carpellate subsessile fruits 5 to 8 mm long. Each capsule contains many minute seeds with long, white cottony hairs.

Seed Production and Dissemination

The seed ripens and is disseminated by late May to late June in Oregon and Washington. but frequently not until mid-July in Idaho and Montana. Abundant seed crops are usually produced every year. Attached to its cotton, the seed is light and buoyant and can be transported long distances by wind and water. Although highly viable, longevity of P. trichocarpa seed under natural conditions may be as short as 2 weeks to a month. This can be increased with cold storage.

Moist seedbeds are essential for high germination, and seedling survival depends on continuously favorable conditions during the first month. Wet bottom lands of rivers and major streams frequently provide such conditions, particularly where bare soil has been exposed or new soil laid down. Germination is epigeal. P. trichocarpa seedlings do not usually become established in abundance after logging unless special measures are taken to prepare the bare, moist seedbeds required for initial establishment. Where seedlings become established in great numbers, they thin out naturally by age 5 because the weaker seedlings of this shade-intolerant species are suppressed.

P. trichocarpa sprouts readily from stumps. After logging operations, it sometimes regenerates naturally from rooting of partially buried fragments of branches. Sprouting from roots occurs. The species also has the ability to abscise shoots complete with green leaves. These shoots drop to the ground and may root where they fall or may be dispersed by water transport. In some situations, abscission may be one means of colonizing exposed sandbars.

[edit ] Range

The native range of P. trichocarpa covers large sections of western North America. It extends northeast from Kodiak Island along Cook Inlet to latitude 62° 30° N. then southeast in southeast Alaska and British Columbia to the forested areas of Washington and Oregon. to the mountains in southern California and northern Baja California (lat. 31° N.). It is also found inland, generally on the west side of the Rocky Mountains. in British Columbia. western Alberta. western Montana. and northern Idaho. Scattered small populations have been noted in southeastern Alberta. eastern Montana. western North Dakota. western Wyoming. Utah. and Nevada. It grows up to elevations of 2100 m.

[edit ] Use as a model species

P. trichocarpa has several qualities which makes it a good model species for trees:

  • Modes genome size (although signicantly larger than the other model plant, Arabidopsis thaliana )
  • Rapid growth (for a tree)
  • Reaches reproductive maturity 4-6 years
  • Economically important
  • It represents a phenotypically diverse genus

For these reasons the species has been extensively studied. Its genome sequence was published in 2006 (see "Genome" below). More than 121 000 expressed sequence tags (ESTs) have been sequenced from it. The wide range of topics studied by using P. trichocarpa include the effects of ethylene. lignin biosynthesis. draught tolerance and wood formation.

[edit ] Economic use

P. trichocarpa wood is ligth-weighted and although not particularly strong, strong for its weight. The wood material has short, fine cellulose fibres which are used the production of high-quality book and magazine paper. The wood is also excellent for production of plywood. Living trees are used as windbreaks. P. trichocarpa contains salicin. and has been used medicinally for fever. pain and inflammation.

P. trichocarpa grows very quickly; trees in plantations in Great Britain have reached 18 m tall in 11 years, and 34 m tall in 28 years (Mitchell 1996). It can reach suitable size for pulp production in 10-15 years and about 25 years for timber production.

It is also grown as an ornamental tree. valued for its fast growth and scented foliage in spring, detectable from over 100 m distance. The roots are however invasive, and it can damage the foundations of buildings on shrinkable clay soils if planted nearby (Mitchell 1996).

[edit ] Genome [edit ] Characteristics [edit ] General information

The sequence of P. trichocarpa is that of an individual female specimen "Nisqually-1". named after the Nisqually River in the Washington state in the USA. where the specimen was collected. The sequencing was performed at the Joint Genome Institute by using the shotgun method. The depth of the sequencing was appoximately 7,5 x (meaning that each base pair was sequenced on average 7,5 times). Genome annotation was done by primarily by the Joint Genome Institute. the Oak Ridge National Laboratory. the Umeå Plant Science Centre and the Genome Canada.

Prior to the publication of P. trichocarpa genome the only available plant genomes were those of thale cress and rice. both of which are herbaceous. P. trichocarpa is the first woody plant genome to be sequenced. Considering the economic importance of wood and wood products, the availability of a tree genome was necessary. The sequence also allows evolutionary comparisons and the elucidation of basic molecular differences between herbaceous and woody plants.

[edit ] Nomenclature

"Trichocarpa" is Greek for "hairy fruits". The following scientific names are now considered synonymous with Populus trichocarpa.

  • P. balsamifera subsp. trichocarpa
  • P. balsamifera var. californica
  • P. hastata
  • P. trichocarpa subsp. hastata
  • P. trichocarpa var. hastata
  • P. trichocarpa var. cupulata
  • P. trichocarpa var. ingrata

Populus trichocarpa classification essay

Populus trichocarpa

Populus trichocarpa (Black Cottonwood ; also known as Western Balsam Poplar or California Poplar ) is a tree species native to western North America. It is used for timber, and is notable as a model organism in plant biology. Its full genome sequence was published in 2006. It is the first, and so far only, tree species ever to be sequenced and contains the largest number of genes ever discovered in any organism.

Description

It is a large tree, growing to a height of 30-50 m and a trunk diameter of over 2 m, which makes it the largest poplar species in the Americas. The bark is grey and covered with lenticels, becoming thick and deeply fissured on old trees. It is normally fairly short-lived, but some trees may live for up to 400 years (Forbes 2006).

The stem is grey in the older parts and light brown in younger parts. The crown is usually roughly conical and quite dense. In large trees the lower branches droop downwards. Spur shoots are common. The wood has a light coloring and a straight grain.

The leaves are 7-20 cm long with a dark green upper side and glaucous light grey-green underside; larger leaves, up to 30 cm long, may be produced on stump sprouts and very vigorous young trees. The leaves are alternate, elliptic with a crenate margin and an acute tip, and reticulate venation (see leaf terminology ). The petiole is reddish. The buds are conical, long, narrow and sticky, with a strong balsam scent in spring when they open.

P. trichocarpa has an extensive and aggressive root system, which can invade and damage drainage systems. Sometimes the roots can even damage the foundations of buildings by drying out the soil.

Reproduction

Flowering and Fruiting

P. trichocarpa is normally dioecious ; male and female catkins are borne on separate trees. The species reaches flowering age at about 10 years. Flowers may appear in early March to late May in [Washington] and Oregon, and sometimes as late as mid-June in northern and interior British Columbia, Idaho, and Montana. Staminate catkins contain 30 to 60 stamens. elongate to 2 to 3 cm, and are deciduous. Pistillate catkins at maturity are 8 to 20 cm long with rotund-ovate. three carpellate subsessile fruits 5 to 8 mm long. Each capsule contains many minute seeds with long, white cottony hairs.

Seed Production and Dissemination

The seed ripens and is disseminated by late May to late June in Oregon and Washington, but frequently not until mid-July in Idaho and Montana. Abundant seed crops are usually produced every year. Attached to its cotton, the seed is light and buoyant and can be transported long distances by wind and water. Although highly viable, longevity of P. trichocarpa seed under natural conditions may be as short as 2 weeks to a month. This can be increased with cold storage.

Moist seedbeds are essential for high germination, and seedling survival depends on continuously favorable conditions during the first month. Wet bottom lands of rivers and major streams frequently provide such conditions, particularly where bare soil has been exposed or new soil laid down. Germination is epigeal. P. trichocarpa seedlings do not usually become established in abundance after logging unless special measures are taken to prepare the bare, moist seedbeds required for initial establishment. Where seedlings become established in great numbers, they thin out naturally by age 5 because the weaker seedlings of this shade-intolerant species are suppressed.

P. trichocarpa sprouts readily from stumps. After logging operations, it sometimes regenerates naturally from rooting of partially buried fragments of branches. Sprouting from roots occurs. The species also has the ability to abscise shoots complete with green leaves. These shoots drop to the ground and may root where they fall or may be dispersed by water transport. In some situations, abscission may be one means of colonizing exposed sandbars.

The native range of P. trichocarpa covers large sections of western North America. It extends northeast from Kodiak Island along Cook Inlet to latitude 62° 30° N. then southeast in southeast Alaska and British Columbia to the forested areas of Washington and Oregon, to the mountains in southern California and northern Baja California (lat. 31° N.). It is also found inland, generally on the west side of the Rocky Mountains, in British Columbia, western Alberta, western Montana, and northern Idaho. Scattered small populations have been noted in southeastern Alberta, eastern Montana, western North Dakota, western Wyoming, Utah, and Nevada. It grows up to elevations of 2100 m.

Populus trichocarpa has been one of the most successful introduction of trees to the otherwise treeless Faroe Islands

Use as a model species

P. trichocarpa has several qualities which makes it a good model species for trees:

  • Modes genome size (although signicantly larger than the other model plant, Arabidopsis thaliana )
  • Rapid growth (for a tree)
  • Reaches reproductive maturity 4-6 years
  • Economically important
  • It represents a phenotypically diverse genus

For these reasons the species has been extensively studied. Its genome sequence was published in 2006 (see "Genome" below). More than 121 000 expressed sequence tags (ESTs) have been sequenced from it. The wide range of topics studied by using P. trichocarpa include the effects of ethylene, lignin biosynthesis, draught tolerance and wood formation.

Economic use

P. trichocarpa wood is light-weight and although not particularly strong, is strong for its weight. The wood material has short, fine cellulose fibres which are used in the production of high-quality book and magazine paper. The wood is also excellent for production of plywood. Living trees are used as windbreaks. P. trichocarpa contains salicin. and has been used medicinally for fever. pain and inflammation.

P. trichocarpa grows very quickly; trees in plantations in Great Britain have reached 18 m tall in 11 years, and 34 m tall in 28 years (Mitchell 1996). It can reach suitable size for pulp production in 10-15 years and about 25 years for timber production.

It is also grown as an ornamental tree, valued for its fast growth and scented foliage in spring, detectable from over 100 m distance. The roots are however invasive, and it can damage the foundations of buildings on shrinkable clay soils if planted nearby (Mitchell 1996).

Characteristics General information

The sequence of P. trichocarpa is that of an individual female specimen "Nisqually-1". named after the Nisqually River in the Washington state in the USA, where the specimen was collected. The sequencing was performed at the Joint Genome Institute by using the shotgun method. The depth of the sequencing was approximately 7,5 x (meaning that each base pair was sequenced on average 7,5 times). Genome annotation was done by primarily by the Joint Genome Institute. the Oak Ridge National Laboratory, the Umeå Plant Science Centre and the Genome Canada.

Prior to the publication of P. trichocarpa genome the only available plant genomes were those of thale cress and rice, both of which are herbaceous. P. trichocarpa is the first woody plant genome to be sequenced. Considering the economic importance of wood and wood products, the availability of a tree genome was necessary. The sequence also allows evolutionary comparisons and the elucidation of basic molecular differences between herbaceous and woody plants.

Nomenclature

"Trichocarpa" is Greek for "hairy fruits". The following scientific names are now considered synonymous with Populus trichocarpa.

  • P. balsamifera subsp. trichocarpa
  • P. balsamifera var. californica
  • P. hastata
  • P. trichocarpa subsp. hastata
  • P. trichocarpa var. hastata
  • P. trichocarpa var. cupulata
  • P. trichocarpa var. ingrata
References
  • P. tricocharpa information at the USDA Forest Service website, written by Dean S. DeBell
  • The Populus Database
  • Populus genome at the JGI website
  • Plants for a Future: Populus trichocarpa
  • Forbes, R. D. (2006). Morrisey Old Growth Cottonwood Forest (pdf file)
  • Mitchell, A. F. (1996). Alan Mitchell's Trees of Britain. Collins. ISBN 0-00-219213-6.