73-661: The cucumber ( Cucumis sativus ) is a widely-cultivated creeping vine plant in the family Cucurbitaceae that bears cylindrical to spherical fruits , which are used as culinary vegetables . Considered an annual plant, there are three main types of cucumber—slicing, pickling , and seedless —within which several cultivars have been created. The cucumber originates in Asia extending from India , Nepal , Bangladesh , China ( Yunnan , Guizhou , Guangxi ), and Northern Thailand , but now grows on most continents , and many different types of cucumber are grown commercially and traded on
146-536: A pollenizer cultivar interplanted, and the number of beehives per unit area is increased, but temperature changes induce male flowers even on these plants, which may be sufficient for pollination to occur. In 2009, an international team of researchers announced they had sequenced the cucumber genome . A study of genetic recombination during meiosis in cucumber provided a high resolution landscape of meiotic DNA double strand-breaks and genetic crossovers . The average number of crossovers per chromosome per meiosis
219-460: A template strand by the DSB strand (see figure below). Nearby homologous regions of the template strand are often used for repair, which can give rise to either insertions or deletions in the genome if a non-homologous but complementary part of the template strand is used. Sequence similarity is a major player in crossover – crossover events are more likely to occur in long regions of close identity on
292-428: A 30% genome wide reduction in crossover numbers, and a large number of meioses with non exchange chromosomes. Nevertheless, this mutant gave rise to spore viability patterns suggesting that segregation of non-exchange chromosomes occurred efficiently. Thus in S. cerevisiae proper segregation apparently does not entirely depend on crossovers between homologous pairs. The grasshopper Melanoplus femur-rubrum
365-432: A chromosome with a ruptured end. She used modified patterns of gene expression on different sectors of leaves of her corn plants to show that transposable elements ("controlling elements") hide in the genome, and their mobility allows them to alter the action of genes at different loci. These elements can also restructure the genome, anywhere from a few nucleotides to whole segments of chromosome. Recombinases and primases lay
438-661: A commercially important example of a bine. The direction of rotation of the shoot tip during climbing is autonomous and does not (as sometimes imagined) derive from the shoot's following the sun around the sky – the direction of twist does not therefore depend upon which side of the equator the plant is growing on. This is shown by the fact that some bines always twine clockwise, including runner bean ( Phaseolus coccineus ) and bindweed ( Convolvulus species), while others twine anticlockwise, including black bryony ( Dioscorea communis ) and climbing honeysuckles ( Lonicera species). The contrasting rotations of bindweed and honeysuckle
511-427: A complete haploid complement of alleles on chromosomes that are independently selected from each pair of chromatids lined up on the metaphase plate. Without recombination, all alleles for those genes linked together on the same chromosome would be inherited together. Meiotic recombination allows a more independent segregation between the two alleles that occupy the positions of single genes, as recombination shuffles
584-425: A condensed space, it is thought that transposon regions undergoing a crossover event are more prone to erroneous complementary match-up; that is to say, a section of a chromosome containing a lot of identical sequences, should it undergo a crossover event, is less certain to match up with a perfectly homologous section of complementary code and more prone to binding with a section of code on a slightly different part of
657-711: A crab meat sauce. They can also be stir fried or used in soups. In 2022, world production of cucumbers and gherkins was 95 million tonnes , led by China with 82% of the total. Cultivated for at least 3,000 years, the cultivated cucumbers "Cucumis sativus" were domesticated in India from wild " C. sativus var. hardwickii ". where a great many varieties have been observed, along with its closest living relative, Cucumis hystrix . Three main cultivar groups of cucumber are namely Eurasian cucumbers (slicing cucumbers eaten raw and immature), East Asian cucumbers (pickling cucumbers) and Xishuangbanna cucumbers. Based on demographic modelling,
730-415: A delicate skin. Most commonly grown in greenhouses, these parthenocarpic cucumbers are often found in grocery markets , shrink-wrapped in plastic. They are marketed as either burpless or seedless, as the seeds and skin of other varieties of cucumbers are said to give some people gas. Cucumber shoots are regularly consumed as a vegetable, especially in rural areas. In Thailand they are often served with
803-590: A foundation of nucleotides along the DNA sequence. One such particular protein complex that is conserved between processes is RAD51 , a well conserved recombinase protein that has been shown to be crucial in DNA repair as well as cross over. Several other genes in D. melanogaster have been linked as well to both processes, by showing that mutants at these specific loci cannot undergo DNA repair or crossing over. Such genes include mei-41, mei-9, hdm, spnA, and brca2. This large group of conserved genes between processes supports
SECTION 10
#1732775435708876-466: A gene. This means that any section of the genome with long sections of repetitive DNA is prone to crossover events. The presence of transposable elements is another influential element of non-homologous crossover. Repetitive regions of code characterize transposable elements; complementary but non-homologous regions are ubiquitous within transposons. Because chromosomal regions composed of transposons have large quantities of identical, repetitious code in
949-412: A general source of mutation within the genome . The specific causes of non-homologous crossover events are unknown, but several influential factors are known to increase the likelihood of an unequal crossover. One common vector leading to unbalanced recombination is the repair of double-strand breaks (DSBs). DSBs are often repaired using homology directed repair, a process which involves invasion of
1022-511: A growth form based on very long stems. This has two purposes. A vine may use rock exposures, other plants, or other supports for growth rather than investing energy in a lot of supportive tissue, enabling the plant to reach sunlight with a minimum investment of energy. This has been a highly successful growth form for plants such as kudzu and Japanese honeysuckle , both of which are invasive exotics in parts of North America. There are some tropical vines that develop skototropism, and grow away from
1095-563: A mild melon aroma and flavor, in part resulting from unsaturated aldehydes , such as (E,Z)-nona-2,6-dienal , and the cis - and trans - isomers of 2-nonenal . The slightly bitter taste of cucumber rind results from cucurbitacins . In general cultivation , cucumbers are classified into three main cultivar groups: slicing, pickled , and seedless/burpless . Cucumbers grown to eat fresh are called slicing cucumbers . The main varieties of slicers mature on vines with large leaves that provide shading. Slicers grown commercially for
1168-665: A scaffold protein called SLX4 may participate in this regulation. Specifically, SLX4 knockout mice largely phenocopies the MUS81 knockout—once again, an elevated class I crossovers while normal chiasmata count. In FANCM knockout mice, the class II pathway is hyperactivated, resulting in increased numbers of crossovers that are independent of the MLH1/MLH3 pathway. In most eukaryotes , a cell carries two versions of each gene , each referred to as an allele . Each parent passes on one allele to each offspring. An individual gamete inherits
1241-409: A situation in which some combinations of genes or genetic markers occur more or less frequently in a population than would be expected from their distances apart. This concept is applied when searching for a gene that may cause a particular disease . This is done by comparing the occurrence of a specific DNA sequence with the appearance of a disease. When a high correlation between the two is found, it
1314-477: A species different from the common cucumber. Pliny also writes about several other varieties of cucumber, including the cultivated cucumber, and remedies from the different types (9 from the cultivated; 5 from the "anguine;" and 26 from the "wild"). Charlemagne had cucumbers grown in his gardens in the 8th/9th century. They were reportedly introduced into England in the early 14th century, lost, then reintroduced approximately 250 years later. The Spaniards (through
1387-550: A species. During DNA replication , each strand of DNA is used as a template for the creation of new strands using a partially-conserved mechanism; proper functioning of this process results in two identical, paired chromosomes, often called sisters. Sister chromatid crossover events are known to occur at a rate of several crossover events per cell per division in eukaryotes. Most of these events involve an exchange of equal amounts of genetic information, but unequal exchanges may occur due to sequence mismatch. These are referred to by
1460-475: A touch stimulus, vanadate -sensitive K , Mg ATPase and Ca -translocating ATPases rapidly increase their activity. This increases transmembrane ion fluxes that appear to be involved in the early stages of tendril coiling. Chromosomal crossover Chromosomal crossover , or crossing over , is the exchange of genetic material during sexual reproduction between two homologous chromosomes ' non-sister chromatids that results in recombinant chromosomes . It
1533-410: A triploid maize plant. She made key findings regarding corn's karyotype, including the size and shape of the chromosomes. McClintock used the prophase and metaphase stages of mitosis to describe the morphology of corn's chromosomes, and later showed the first ever cytological demonstration of crossing over in meiosis. Working with student Harriet Creighton, McClintock also made significant contributions to
SECTION 20
#17327754357081606-401: A variety of names, including non-homologous crossover, unequal crossover, and unbalanced recombination, and result in an insertion or deletion of genetic information into the chromosome. While rare compared to homologous crossover events, these mutations are drastic, affecting many loci at the same time. They are considered the main driver behind the generation of gene duplications and are
1679-593: Is a woody shrub-vine which climbs without clinging roots, tendrils, or thorns. It directs its stem into a crevice in the bark of fibrous barked trees (such as bald cypress ) where the stem adopts a flattened profile and grows up the tree underneath the host tree's outer bark. The fetterbush then sends out branches that emerge near the top of the tree. Most vines are flowering plants. These may be divided into woody vines or lianas , such as akebia wisteria , kiwifruit , and common ivy , and herbaceous (nonwoody) vines, such as morning glory . One odd group of vining plants
1752-421: Is because recombination is greatly influenced by the proximity of one gene to another. If two genes are located close together on a chromosome, the likelihood that a recombination event will separate these two genes is less than if they were farther apart. Genetic linkage describes the tendency of genes to be inherited together as a result of their location on the same chromosome. Linkage disequilibrium describes
1825-545: Is classified as a pepo , a type of botanical berry with a hard outer rind and no internal divisions. However, much like tomatoes and squashes , it is often perceived, prepared, and eaten as a vegetable . Most cucumber cultivars are seeded and require pollination. For this purpose, thousands of honey beehives are annually carried to cucumber fields just before bloom. Cucumbers may also be pollinated via bumblebees and several other bee species. Most cucumbers that require pollination are self-incompatible , thus requiring
1898-635: Is dead of eating cowcumbers, of which the other day I heard of another, I think. John Evelyn in 1699 wrote that the cucumber, 'however dress'd, was thought fit to be thrown away, being accounted little better than poyson (poison)'. According to 18th-century British writer Samuel Johnson , it was commonly said among English physicians that a cucumber "should be well sliced, and dressed with pepper and vinegar, and then thrown out, as good for nothing." A copper etching made by Maddalena Bouchard between 1772 and 1793 shows this plant to have smaller, almost bean-shaped fruits, and small yellow flowers. The small form of
1971-628: Is known as a chiasma . The Holliday junction is a tetrahedral structure which can be 'pulled' by other recombinases, moving it along the four-stranded structure. The MSH4 and MSH5 proteins form a hetero-oligomeric structure ( heterodimer ) in yeast and humans. In the yeast Saccharomyces cerevisiae MSH4 and MSH5 act specifically to facilitate crossovers between homologous chromosomes during meiosis . The MSH4/MSH5 complex binds and stabilizes double Holliday junctions and promotes their resolution into crossover products. An MSH4 hypomorphic (partially functional) mutant of S. cerevisiae showed
2044-406: Is likely that the appropriate gene sequence is really closer Crossovers typically occur between homologous regions of matching chromosomes , but similarities in sequence and other factors can result in mismatched alignments. Most DNA is composed of base pair sequences repeated very large numbers of times. These repetitious segments, often referred to as satellites, are fairly homogeneous among
2117-419: Is linked to DNA repair or bacterial transformation, as the two do not appear to be mutually exclusive. It is likely that crossing over may have evolved from bacterial transformation, which in turn developed from DNA repair, thus explaining the links between all three processes. Meiotic recombination may be initiated by double-stranded breaks that are introduced into the DNA by exposure to DNA damaging agents, or
2190-515: Is mediated by changes in turgor pressure mediated by volume changes in the epidermal cells of the bending zone. Climbing vines can take on many unique characteristics in response to changes in their environments. Climbing vines can induce chemical defenses and modify their biomass allocation in response to herbivores. In particular, the twisting vine Convolvulus arvensis increases its twining in response to herbivore-associated leaf damage, which may lead to reduced future herbivory. Additionally,
2263-413: Is one of the final phases of genetic recombination , which occurs in the pachytene stage of prophase I of meiosis during a process called synapsis . Synapsis begins before the synaptonemal complex develops and is not completed until near the end of prophase I. Crossover usually occurs when matching regions on matching chromosomes break and then reconnect to the other chromosome. Crossing over
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2336-822: Is optimized by the installation of trellis netting. Gardeners can use the tendency of climbing plants to grow quickly. If a plant display is wanted quickly, a climber can achieve this. Climbers can be trained over walls, pergolas, fences, etc. Climbers can be grown over other plants to provide additional attraction. Artificial support can also be provided. Some climbers climb by themselves; others need work, such as tying them in and training them. Vines widely differ in size, form and evolutionary origin. Darwin classified climbing groups based on their climbing method. He classified five classes of vines – twining plants, leaf climbers, tendril bearers, root climbers and hook climbers. Vines are unique in that they have multiple evolutionary origins. They usually reside in tropical locations and have
2409-534: Is the fern genus Lygodium , called climbing ferns . The stem does not climb, but rather the fronds (leaves) do. The fronds unroll from the tip, and theoretically never stop growing; they can form thickets as they unroll over other plants, rockfaces, and fences. A twining vine, also known as a bine , is one that climbs by its shoots growing in a helix , in contrast to vines that climb using tendrils or suckers. Many bines have rough stems or downward-pointing bristles to aid their grip. Hops (used in flavoring beer) are
2482-471: Is the restoration of the parental genotype. One class of MMR in particular, MutSβ, is known to initiate the correction of insertion-deletion mismatches of up to 16 nucleotides. Little is known about the excision process in eukaryotes, but E. coli excisions involve the cleaving of a nick on either the 5' or 3' strand, after which DNA helicase and DNA polymerase III bind and generate single-stranded proteins, which are digested by exonucleases and attached to
2555-624: The Italian Christopher Columbus ) brought cucumbers to Haiti in 1494. In 1535, Jacques Cartier , a French explorer, found "very great cucumbers" grown on the site of what is now Montreal . Throughout the 16th century, European trappers, traders, bison hunters, and explorers bartered for the products of American Indian agriculture . The tribes of the Great Plains and the Rocky Mountains learned from
2628-467: The Spo11 protein. One or more exonucleases then digest the 5' ends generated by the double-stranded breaks to produce 3' single-stranded DNA tails (see diagram). The meiosis-specific recombinase Dmc1 and the general recombinase Rad51 coat the single-stranded DNA to form nucleoprotein filaments. The recombinases catalyze invasion of the opposite chromatid by the single-stranded DNA from one end of
2701-421: The global market . In North America , the term wild cucumber refers to plants in the genera Echinocystis and Marah , though the two are not closely related. The cucumber is a creeping vine that roots in the ground and grows up trellises or other supporting frames, wrapping around supports with thin, spiraling tendrils . The plant may also root in a soilless medium , whereby it will sprawl along
2774-755: The pollen of another plant in order to form seeds and fruit. Some self-compatible cultivars exist that are related to the 'Lemon cucumber' cultivar. A few cultivars of cucumber are parthenocarpic , the blossoms of which create seedless fruit without pollination , which degrades the eating quality of these cultivar. In the United States , these are usually grown in greenhouses , where bees are excluded. In Europe , they are grown outdoors in some regions, where bees are likewise excluded. Traditional cultivars produce male blossoms first, then female, in about equivalent numbers. Newer gynoecious hybrid cultivars produce almost all female blossoms. They may have
2847-466: The statistical probability that another offspring will have the same combination. This principle of " independent assortment " of genes is fundamental to genetic inheritance. However, the frequency of recombination is actually not the same for all gene combinations. This leads to the notion of " genetic distance ", which is a measure of recombination frequency averaged over a (suitably large) sample of pedigrees. Loosely speaking, one may say that this
2920-877: The East Asian C. sativus cultivars diverged from the Indian cultivars c. 2500 years ago. It was probably introduced to Europe by the Greeks or Romans . Records of cucumber cultivation appear in France in the 9th century, England in the 14th century, and in North America by the mid-16th century. According to Pliny the Elder , the Emperor Tiberius had the cucumber on his table daily during summer and winter. In order to have it available for his table every day of
2993-800: The North American market are generally longer, smoother, more uniform in color, and have much tougher skin. In contrast, those in other countries, often called European cucumbers , are smaller and have thinner, more delicate skin, often with fewer seeds, thus are often sold in plastic skin for protection. This variety may also be called a telegraph cucumber , particularly in Australasia . Pickling with brine , sugar, vinegar , and spices creates various flavored products from cucumbers and other foods. Although any cucumber can be pickled, commercial pickles are made from cucumbers specially bred for uniformity of length-to-diameter ratio and lack of voids in
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3066-1146: The Reverend Francis Higginson produced a book called New-Englands Plantation in which, describing a garden on Conant's Island in Boston Harbor known as The Governor's Garden , he states: The countrie aboundeth naturally with store of roots of great varietie [ sic ] and good to eat. Our turnips, parsnips, and carrots are here both bigger and sweeter than is ordinary to be found in England. Here are store of pompions, cowcumbers, and other things of that nature which I know not... In New England Prospect (1633, England), William Wood published observations he made in 1629 in America: The ground affords very good kitchin gardens, for Turneps, Parsnips, Carrots, Radishes, and Pompions, Muskmillons, Isquoter-squashes, coucumbars, Onyons, and whatever grows well in England grows as well there, many things being better and larger. [ sic ] In
3139-573: The Spanish how to grow European crops. The farmers on the Great Plains included the Mandan and Abenaki . They obtained cucumbers and watermelons from the Spanish, and added them to the crops they were already growing, including several varieties of corn and beans , pumpkins , squash , and gourd plants. The Iroquois were also growing them when the first Europeans visited them. In 1630,
3212-427: The allele content between homologous chromosomes. Recombination results in a new arrangement of maternal and paternal alleles on the same chromosome. Although the same genes appear in the same order, some alleles are different. In this way, it is theoretically possible to have any combination of parental alleles in an offspring, and the fact that two alleles appear together in one offspring does not have any influence on
3285-406: The break. Next, the 3' end of the invading DNA primes DNA synthesis, causing displacement of the complementary strand, which subsequently anneals to the single-stranded DNA generated from the other end of the initial double-stranded break. The structure that results is a cross-strand exchange , also known as a Holliday junction . The contact between two chromatids that will soon undergo crossing-over
3358-540: The chromosome. This results in unbalanced recombination, as genetic information may be either inserted or deleted into the new chromosome, depending on where the recombination occurred. While the motivating factors behind unequal recombination remain obscure, elements of the physical mechanism have been elucidated. Mismatch repair (MMR) proteins, for instance, are a well-known regulatory family of proteins, responsible for regulating mismatched sequences of DNA during replication and escape regulation. The operative goal of MMRs
3431-481: The class I crossovers. The remaining are the result of the class II pathway, which is regulated by MUS81 endonuclease and FANCM translocase. There are interconnections between these two pathways—class I crossovers can compensate for the loss of class II pathway. In MUS81 knockout mice, class I crossovers are elevated, while total crossover counts at chiasmata are normal. However, the mechanisms underlining this crosstalk are not well understood. A recent study suggests that
3504-674: The cucumber is figured in Herbals of the 16th century, however stating that "[i]f hung in a tube while in blossom, the Cucumber will grow to a most surprising length." Vine#Horticultural climbing plants A vine (from Latin vīnea ' grapevine , vineyard '; from vīnum 'wine') is any plant with a growth habit of trailing or scandent (that is, climbing) stems, lianas, or runners. The word vine can also refer to such stems or runners themselves, for instance, when used in wicker work. In parts of
3577-489: The early modern Dutch gurken or augurken ('small pickled cucumber'). The term is also used in the name for Cucumis anguria , the West Indian gherkin , a closely related species. Burpless cucumbers are sweeter and have a thinner skin than other varieties of cucumber. They are reputed to be easy to digest and to have a pleasant taste. They can grow as long as 60 centimeters (2 ft), are nearly seedless, and have
3650-470: The early understanding of codependency of linked genes. Crossing over and DNA repair are very similar processes, which utilize many of the same protein complexes. In her report, "The Significance of Responses of the Genome to Challenge", McClintock studied corn to show how corn's genome would change itself to overcome threats to its survival. She used 450 self-pollinated plants that received from each parent
3723-457: The experimental results of his research on the heredity of Drosophila . The physical basis of crossing over was first demonstrated by Harriet Creighton and Barbara McClintock in 1931. The linked frequency of crossing over between two gene loci ( markers ) is the crossing-over value . For fixed set of genetic and environmental conditions, recombination in a particular region of a linkage structure ( chromosome ) tends to be constant and
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#17327754357083796-593: The flesh. Those cucumbers intended for pickling, called picklers , grow to about 7 to 10 cm (3 to 4 in) long and 2.5 cm (1 in) wide. Compared to slicers, picklers tend to be shorter, thicker, less-regularly shaped, and have bumpy skin with tiny white or black-dotted spines. Color can vary from creamy yellow to pale or dark green. Gherkins , also called cornichons , or baby pickles , are small cucumbers, typically those 2.5 to 12.5 centimetres (1 to 5 in) in length, often with bumpy skin, which are typically used for pickling. The word gherkin comes from
3869-405: The formation of overhangs on the sides of the broken DNA strand, allowing for the annealing of a new strand. Bacterial transformation itself has been linked to DNA repair many times. The second theory comes from the idea that meiosis evolved from bacterial transformation , with the function of propagating genetic diversity. Thus, this evidence suggests that it is a question of whether cross over
3942-410: The ground in lieu of a supporting structure. The vine has large leaves that form a canopy over the fruits. The fruit of typical cultivars of cucumber is roughly cylindrical , but elongated with tapered ends, and may be as large as 62 centimeters (24 in) long and 10 centimeters (4 in) in diameter. Cucumber fruits consist of 95% water (see nutrition table). In botanical terms, the cucumber
4015-517: The idea that photosynthetic responses are closely related to climbing mechanisms. Temperate twining vines, which twist tightly around supports, are typically poorly adapted for climbing beneath closed canopies due to their smaller support diameter and shade intolerance. In contrast, tendril vines usually grow on the forest floor and onto trees until they reach the surface of the canopy, suggesting that they have greater physiological plasticity. It has also been suggested that twining vines' revolving growth
4088-505: The later 17th century, a prejudice developed against uncooked vegetables and fruits. A number of articles in contemporary health publications stated that uncooked plants brought on summer diseases and should be forbidden to children. The cucumber kept this reputation for an inordinate period of time, "fit only for consumption by cows," which some believe is why it gained the name, cowcumber . Samuel Pepys wrote in his diary on 22 August 1663: [T]his day Sir W. Batten tells me that Mr. Newburne
4161-506: The leaves, cotyledons , pedicel , carpopodium , and fruit. Raw cucumber (with peel ) is 95% water, 4% carbohydrates , 1% protein , and contains negligible fat . A 100-gram ( 3 + 1 ⁄ 2 -ounce) reference serving provides 65 kilojoules (16 kilocalories) of food energy . It has a low content of micronutrients : it is notable only for vitamin K , at 14% of the Daily Value (table). Depending on variety, cucumbers may have
4234-482: The light, a type of negative phototropism . Growth away from light allows the vine to reach a tree trunk, which it can then climb to brighter regions. The vine growth form may also enable plants to colonize large areas quickly, even without climbing high. This is the case with periwinkle and ground ivy . It is also an adaptation to life in areas where small patches of fertile soil are adjacent to exposed areas with more sunlight but little or no soil. A vine can root in
4307-447: The origins of crossing-over, coming from the different theories on the origin of meiosis . The first theory rests upon the idea that meiosis evolved as another method of DNA repair , and thus crossing-over is a novel way to replace possibly damaged sections of DNA. The second theory comes from the idea that meiosis evolved from bacterial transformation , with the function of propagating diversity. In 1931, Barbara McClintock discovered
4380-553: The protection of frames glazed with mirrorstone. Reportedly, they were also cultivated in specularia , cucumber houses glazed with oiled cloth. Pliny describes the Italian fruit as very small, probably like a gherkin . He also describes the preparation of a medication known as elaterium . However, some scholars believe that he was instead referring to Ecballium elaterium , known in pre- Linnean times as Cucumis silvestris or Cucumis asininus ('wild cucumber' or 'donkey cucumber'),
4453-432: The same is then true for the crossing-over value which is used in the production of genetic maps . When Hotta et al. in 1977 compared meiotic crossing-over ( recombination ) in lily and mouse they concluded that diverse eukaryotes share a common pattern. This finding suggested that chromosomal crossing over is a general characteristic of eukaryotic meiosis. There are two popular and overlapping theories that explain
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#17327754357084526-446: The soil but have most of its leaves in the brighter, exposed area, getting the best of both environments. The evolution of a climbing habit has been implicated as a key innovation associated with the evolutionary success and diversification of a number of taxonomic groups of plants. It has evolved independently in several plant families, using many different climbing methods, such as: The climbing fetterbush ( Pieris phillyreifolia )
4599-506: The tendrils are highly sensitive to touch and the coiling action is mediated by the hormones octadecanoids, jasmonates and indole-3-acetic acid . The touch stimulus and hormones may interact via volatile compounds or internal oscillation patterns. Research has found the presence of ion translocating ATPases in the Bryonia dioica species of plants, which has implications for a possible ion mediation tendril curling mechanism. In response to
4672-404: The tendrils of perennial vine Cayratia japonica are more likely to coil around nearby plants of another species than nearby plants of the same species in natural and experimental settings. This ability, which has only been previously documented in roots, demonstrates the vine's ability to distinguish whether another plant is of the same species as itself or a different one. In tendrilled vines,
4745-568: The theory of a close evolutionary relationship. Furthermore, DNA repair and crossover have been found to favor similar regions on chromosomes. In an experiment using radiation hybrid mapping on wheat's ( Triticum aestivum L. ) 3B chromosome, crossing over and DNA repair were found to occur predominantly in the same regions. Furthermore, crossing over has been correlated to occur in response to stressful, and likely DNA damaging, conditions. The process of bacterial transformation also shares many similarities with chromosomal cross over, particularly in
4818-431: The unique ability to climb. Vines are able to grow in both deep shade and full sun due to their uniquely wide range of phenotypic plasticity . This climbing action prevents shading by neighbors and allows the vine to grow out of reach of herbivores. The environment where a vine can grow successfully is determined by the climbing mechanism of a vine and how far it can spread across supports. There are many theories supporting
4891-476: The world, including the British Isles, the term "vine" usually applies exclusively to grapevines, while the term "climber" is used for all climbing plants. Certain plants always grow as vines, while a few grow as vines only part of the time. For instance, poison ivy and bittersweet can grow as low shrubs when support is not available, but will become vines when support is available. A vine displays
4964-479: The year, the Romans reportedly used artificial methods of growing (similar to the greenhouse system ), whereby mirrorstone refers to Pliny's lapis specularis , believed to have been sheet mica : Indeed, he was never without it; for he had raised beds made in frames upon wheels, by means of which the cucumbers were moved and exposed to the full heat of the sun; while, in winter, they were withdrawn, and placed under
5037-487: The zygotene-early pachytene stages caused a significant increase in mean cell chiasma frequency. Chiasma frequency was scored at the later diplotene-diakinesis stages of meiosis. These results suggest that X-rays induce DNA damages that are repaired by a crossover pathway leading to chiasma formation. Double strand breaks (DSBs) are repaired by two pathways to generate crossovers in eukaryotes. The majority of them are repaired by MutL homologs MLH1 and MLH3, which defines
5110-472: Was 0.92 to 0.99. Phytochemicals in cucumbers may discourage natural foraging by herbivores , such as insects, nematodes or wildlife . As a possible defense mechanism, cucumbers produce cucurbitacin C , which causes a bitter taste in some cucumber varieties. This potential mechanism is under preliminary research to identify whether cucumbers are able to deter herbivores and environmental stresses by using an intrinsic chemical defense , particularly in
5183-414: Was described, in theory, by Thomas Hunt Morgan ; the term crossover was coined by Morgan and Eleth Cattell. Hunt relied on the discovery of Frans Alfons Janssens who described the phenomenon in 1909 and had called it "chiasmatypie". The term chiasma is linked, if not identical, to chromosomal crossover. Morgan immediately saw the great importance of Janssens' cytological interpretation of chiasmata to
5256-414: Was exposed to an acute dose of X-rays during each individual stage of meiosis , and chiasma frequency was measured. Irradiation during the leptotene - zygotene stages of meiosis (that is, prior to the pachytene period in which crossover recombination occurs) was found to increase subsequent chiasma frequency. Similarly, in the grasshopper Chorthippus brunneus , exposure to X-irradiation during
5329-461: Was the theme of the satirical song "Misalliance", written and sung by Michael Flanders and Donald Swann (but the lyrics confuse the direction of twining, describing honeysuckle as right-handed and bindweed as left-handed). The term "vine" also applies to Cucurbitaceae like cucumbers where botanists refer to creeping vines; in commercial agriculture the natural tendency of coiling tendrils to attach themselves to pre-existing structures or espaliers
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