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39-527: Siyang is famous for its poplar tree. It is the earliest Chinese county and the Italian poplar tree were the highest poplar coverage of China as China polar tree industry county of the most developed county forestry of China and to learn the unique honor of "China YiYang township of" title of county the name. In addition, SiYang because has the Chinese unique poplar museum, and hold China unique YangShuJie which

78-412: A phosphodiester bond and the bases are held together by hydrogen bonds . Nuclear DNA and mitochondrial DNA differ in many ways, starting with location and structure. Nuclear DNA is located within the nucleus of eukaryote cells and usually has two copies per cell while mitochondrial DNA is located in the mitochondria and contains 100–1,000 copies per cell. The structure of nuclear DNA chromosomes

117-536: A case. Techniques used include polymerase chain reaction (PCR), which allows one to utilize very small amounts of DNA by making copies of targeted regions on the molecule, also known as short tandem repeats (STRs). Like mitosis , meiosis is a form of eukaryotic cell division . Meiosis gives rise to four unique daughter cells, each of which has half the number of chromosomes as the parent cell. Because meiosis creates cells that are destined to become gametes (or reproductive cells), this reduction in chromosome number

156-428: A cell goes through an interphase period in which it grows, replicates its chromosomes, and checks all of its systems to ensure that it is ready to divide. Like mitosis, meiosis also has distinct stages called prophase , metaphase , anaphase , and telophase . A key difference, however, is that during meiosis, each of these phases occurs twice — once during the first round of division, called meiosis I, and again during

195-480: A clear indication of likely hybrid origin. Hybridisation continues to be common in the genus, with several hybrids between species in different sections known. There are currently 57 accepted species in the genus. Some of the most easily identifiable fossils of this genus belongs to Poplus wilmattae , which come from the Late Paleocene of North America about 58 million years ago. However, fossils from

234-480: A diverse set of DNA repair processes that remove nuclear DNA damages. These repair processes include base excision repair , nucleotide excision repair , homologous recombinational repair, non-homologous end joining and microhomology-mediated end joining . Such repair processes are essential for maintaining nuclear DNA stability. Failure of repair activity to keep up with the occurrence of damages has various negative consequences. Nuclear DNA damages, as well as

273-408: A large plywood industry reliant upon poplar. It is graded according to sizes known as "over" (over 24 inches (610 mm)), "under" (18–24 inches (460–610 mm)), and "sokta" (less than 18 inches (460 mm)). Although the wood from Populus is known as poplar wood, a common high-quality hardwood "poplar" with a greenish colour is actually from an unrelated genus Liriodendron . Populus wood

312-421: A particularly resonant tone. Similarly, though typically it is considered to have a less attractive grain than the traditional sitka spruce , poplar is beginning to be targeted by some harp luthiers as a sustainable and even superior alternative for their sound boards : in these cases another hardwood veneer is sometimes applied to the resonant poplar base both for cosmetic reasons, and supposedly to fine-tune

351-627: A positive energy balance and a high energy efficiency . Biofuel is another option for using poplar as bioenergy supply. In the United States, scientists studied converting short rotation coppice poplar into sugars for biofuel (e.g. ethanol) production. Considering the relative cheap price, the process of making biofuel from SRC can be economically feasible, although the conversion yield from short rotation coppice (as juvenile crops) were lower than regular mature wood. Besides biochemical conversion, thermochemical conversion (e.g. fast pyrolysis)

390-533: A series of short DNA segments called Okazaki fragments . Each Okazaki fragment requires a separate RNA primer. As the Okazaki fragments are synthesized, the RNA primers are replaced with DNA nucleotides and the fragments are bonded together in a continuous complementary strand. Damage of nuclear DNA is a persistent problem arising from a variety of disruptive endogenous and exogenous sources. Eukaryotes have evolved

429-476: A short sequence of RNA nucleotides, complementary to a small, initial section of the DNA strand being prepared for replication. DNA polymerase is then able to add DNA nucleotides to the RNA primer and thus begin the process of constructing a new complementary strand of DNA. Later the RNA primer is enzymatically removed and replaced with the appropriate sequence of DNA nucleotides. Because the two complementary strands of

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468-828: A substantial reduction in weight. In addition to the foliage and other parts of Populus species being consumed by animals, the starchy sap layer (underneath the outer bark) is edible to humans, both raw and cooked. In Pakistan, poplar is grown on a commercial level by farmers in Punjab, Sindh, and Khyber Pakhtunkhwa Provinces. However, all varieties are seriously susceptible to termite attack, causing significant losses to poplar every year. Logs of poplar are therefore also used as bait in termite traps for biocontrol of termites in crops. Interest exists in using poplar as an energy crop for biomass , in energy forestry systems, particularly in light of its high energy-in to energy-out ratio, large carbon mitigation potential, and fast growth. In

507-421: A template to guide the synthesis of the new complementary polynucleotide of DNA. The DNA single-strand template serves to guide the synthesis of a complementary strand of DNA. DNA replication begins at a specific site in the DNA molecule called the origin of replication . The enzyme helicase unwinds and separates a portion of the DNA molecule after which single-strand binding proteins react with and stabilize

546-658: Is a double helix , with two strands wound around each other, a structure first described by Francis Crick and James D. Watson (1953) using data collected by Rosalind Franklin . Each strand is a long polymer chain of repeating nucleotides . Each nucleotide is composed of a five-carbon sugar, a phosphate group, and an organic base. Nucleotides are distinguished by their bases: purines , large bases that include adenine and guanine ; and pyrimidines , small bases that include thymine and cytosine . Chargaff's rules state that adenine always pairs with thymine, and guanine always with cytosine. The phosphate groups are held together by

585-513: Is a lighter, more porous material. Its flexibility and close grain make it suitable for a number of applications, similar to those of willow. The Greeks and Etruscans made shields of poplar, and Pliny the Elder also recommended poplar for this purpose. Poplar continued to be used for shield construction through the Middle Ages and was renowned for a durability similar to that of oak, but with

624-523: Is critical — without it, the union of two gametes during fertilization would result in offspring with twice the normal number of chromosomes. Meiosis creates new combinations of genetic material in each of the four daughter cells. These new combinations result from the exchange of DNA between paired chromosomes. Such an exchange means that the gametes produced through meiosis often exhibit considerable genetic variation. Meiosis involves two rounds of nuclear division, not just one. Prior to undergoing meiosis,

663-608: Is famous and well-known. At present, Siyang County has 11 towns and 5 townships. This Jiangsu location article is a stub . You can help Misplaced Pages by expanding it . Populus See text Populus is a genus of 25–30 species of deciduous flowering plants in the family Salicaceae , native to most of the Northern Hemisphere . English names variously applied to different species include poplar ( / ˈ p ɒ p l ər / ), aspen , and cottonwood . The western balsam poplar ( P. trichocarpa )

702-601: Is less than 0.3% while that of mitochondrial DNA is generally higher. Nuclear DNA is known as the molecule of life and contains the genetic instructions for the development of all eukaryotic organisms. It is found in almost every cell in the human body, with exceptions such as red blood cells . Everyone has a unique genetic blueprint, even identical twins. Forensic departments such as the Bureau of Criminal Apprehension (BCA) and Federal Bureau of Investigation (FBI) are able to use techniques involving nuclear DNA to compare samples in

741-434: Is linear with open ends and includes 46 chromosomes and contains for example 3 billion nucleotides in humans while the structure of Mitochondrial DNA chromosome is usually closed, circular, and contains for example 16,569 nucleotides in humans. Nuclear DNA in animals is diploid , ordinarily inheriting the DNA from two parents, while mitochondrial DNA is haploid , coming only from the mother. The mutation rate for nuclear DNA

780-417: Is very variable even on a single tree, typically with small leaves on side shoots, and very large leaves on strong-growing lead shoots. The leaves often turn bright gold to yellow before they fall during autumn. The flowers are mostly dioecious (rarely monoecious ) and appear in early spring before the leaves. They are borne in long, drooping, sessile or pedunculate catkins produced from buds formed in

819-575: The mutations and epigenetic alterations that such damages cause, are considered to be a major cause of cancer . Nuclear DNA damages are also implicated in aging and neurodegenerative diseases . Nuclear DNA is subject to mutation . A major cause of mutation is inaccurate DNA replication , often by specialized DNA polymerases that synthesize past DNA damages in the template strand (error-prone trans-lesion synthesis ). Mutations also arise by inaccurate DNA repair. The microhomology-mediated end joining pathway for repair of double-strand breaks

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858-661: The Cretaceous of this genus have been found in Tibet and Heilongjiang, China. Poplars of the cottonwood section are often wetlands or riparian trees. The aspens are among the most important boreal broadleaf trees. Poplars and aspens are important food plants for the larvae of a large number of Lepidoptera species. Pleurotus populinus , the aspen oyster mushroom, is found exclusively on dead wood of Populus trees in North America. Several species of Populus in

897-407: The DNA molecule are oriented in opposite directions and the DNA polymerase can only accommodate replication in one direction, two different mechanisms for copying the strands of DNA are employed. One strand is replicated continuously towards unwinding, separating the portion of the original DNA molecule; while the other strand is replicated discontinuously in the opposite direction with the formation of

936-548: The Lonely Poplars Grow"). In 1973, the 15 white poplars still left (with age ranges between 233 and 371 years) were declared natural monuments. In Ukraine, one of neighborhoods of Kyiv is named after Populus nigra as Osokorky , a local name. Nuclear DNA Nuclear DNA ( nDNA ), or nuclear deoxyribonucleic acid , is the DNA contained within each cell nucleus of a eukaryotic organism . It encodes for

975-500: The United Kingdom and other parts of Europe have experienced heavy dieback ; this is thought in part to be due to Sesia apiformis which bores into the trunk of the tree during its larval stage. Many poplars are grown as ornamental trees , with numerous cultivars used. They have the advantage of growing to a very large size at a rapid pace. Almost all poplars take root readily from cuttings or where broken branches lie on

1014-464: The United Kingdom, poplar (as with fellow energy crop willow) is typically grown in a short rotation coppice system for two to five years (with single or multiple stems), then harvested and burned - the yield of some varieties can be as high as 12 oven-dry tonnes per hectare every year. In warmer regions like Italy this crop can produce up to 13.8, 16.4 oven-dry tonnes of biomass per hectare every year for biannual and triennial cutting cycles also showing

1053-731: The acoustic properties. Lombardy poplars are frequently used as a windbreak around agricultural fields to protect against wind erosion. Logs from the poplar provide a growing medium for shiitake mushrooms. Poplar represents a suitable candidate for phytoremediation since it has the ability to remove and store harmful pollutants in its trunk while also removing air pollution. This plant has been successfully used to target many types of pollutants including trace element (TEs) in soil and sewage sludge , Polychlorinated Biphenyl (PCBs), Trichloroethylene (TCE), Polycyclic Aromatic Hydrocarbon (PAHs). Two notable poems in English lament

1092-499: The axils of the leaves from the previous year. The flowers are each seated in a cup-shaped disk which is borne on the base of a scale which is itself attached to the rachis of the catkin. The scales are obovate, lobed, and fringed, membranous, hairy or smooth, and usually caducous. The male flowers are without calyx or corolla , and comprise a group of four to 60 stamens inserted on a disk; filaments are short and pale yellow; anthers are oblong, purple or red, introrse, and two-celled;

1131-431: The basis of leaf and flower characters; this classification is followed below. Recent genetic studies have largely supported this, confirming some previously suspected reticulate evolution due to past hybridisation and introgression events between the groups. Some species (noted below) had differing relationships indicated by their nuclear DNA (paternally inherited) and chloroplast DNA sequences (maternally inherited),

1170-634: The cells open longitudinally. The female flower also has no calyx or corolla, and comprises a single-celled ovary seated in a cup-shaped disk. The style is short, with two to four stigmata, variously lobed, and numerous ovules. Pollination is by wind, with the female catkins lengthening considerably between pollination and maturity. The fruit is a two- to four-valved dehiscent capsule , green to reddish-brown, mature in midsummer, containing numerous minute, light-brown seeds surrounded by tufts of long, soft, white hairs aiding wind dispersal. The genus Populus has traditionally been divided into six sections on

1209-461: The cutting down of poplars, William Cowper 's "The Poplar Field" and Gerard Manley Hopkins ' " Binsey Poplars felled 1879". In Billie Holiday 's " Strange Fruit ", she sings "Black bodies swinging in the southern breeze/Strange fruit hanging from the poplar trees…". The Odd Poplars Alley, in Iași , Romania, is one of the spots where Mihai Eminescu sought inspiration in his works (the poem "Down Where

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1248-469: The ground (they also often have remarkable suckering abilities, and can form huge colonies from a single original tree, such as the famous Pando forest made of thousands of Populus tremuloides clones). Trees with fastigiate (erect, columnar) branching are particularly popular, and are widely grown across Europe and southwest Asia. However, like willows , poplars have very vigorous and invasive root systems stretching up to 40 metres (130 ft) from

1287-423: The majority of the genome in eukaryotes, with mitochondrial DNA and plastid DNA coding for the rest. It adheres to Mendelian inheritance , with information coming from two parents, one male and one female—rather than matrilineally (through the mother) as in mitochondrial DNA. Nuclear DNA is a nucleic acid , a polymeric biomolecule or biopolymer , found in the nucleus of eukaryotic cells. Its structure

1326-403: The related willows ) the terminal bud present. The leaves are spirally arranged, and vary in shape from triangular to circular or (rarely) lobed, and with a long petiole ; in species in the sections Populus and Aigeiros , the petioles are laterally flattened, so that breezes easily cause the leaves to wobble back and forth, giving the whole tree a "twinkling" appearance in a breeze. Leaf size

1365-477: The second round of division, called meiosis II. Prior to cell division, the DNA material in the original cell must be duplicated so that after cell division, each new cell contains the full amount of DNA material. The process of DNA duplication is usually called replication . The replication is termed semiconservative since each new cell contains one strand of original DNA and one newly synthesized strand of DNA. The original polynucleotide strand of DNA serves as

1404-419: The separated, single-stranded sections of the DNA molecule. The enzyme complex DNA polymerase engages the separated portion of the molecule and initiates the process of replication. DNA polymerase can only connect new DNA nucleotides to a pre-existing chain of nucleotides. Therefore, replication begins as an enzyme called primase assembles an RNA primer at the origin of replication. The RNA primer consists of

1443-817: The trees; planting close to houses or ceramic water pipes may result in damaged foundations and cracked walls and pipes due to their search for moisture. A simple, reproducible, high-frequency micropropagation protocol in eastern cottonwood Populus deltoides has been reported by Yadav et al. 2009. In India, the poplar is grown commercially by farmers, mainly in the Punjab region. Common poplar varieties are: The trees are grown from kalam or cuttings, harvested annually in January and February, and commercially available up to 15   November. Poplars are most commonly used to make plywood : Yamuna Nagar in Haryana state has

1482-599: Was also studied for making biofuel from short rotation coppice poplar and was found to have higher energy recovery than that from bioconversion. Poplar was the most common wood used in Italy for panel paintings ; the Mona Lisa and most famous early Italian Renaissance paintings are on poplar. The wood is generally white, often with a slightly yellowish colour. Some stringed instruments are made with one-piece poplar backs; violas made in this fashion are said to have

1521-486: Was the first tree to have its full DNA code determined by DNA sequencing , in 2006. The genus has a large genetic diversity, and can grow from 15–50 m (49–164 ft) tall, with trunks up to 2.5 m (8 ft) in diameter. The bark on young trees is smooth and white to greenish or dark gray, and often has conspicuous lenticels ; on old trees, it remains smooth in some species, but becomes rough and deeply fissured in others. The shoots are stout, with (unlike in

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