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91-754: Carambola fruits contain oxalic acid and the neurotoxin caramboxin . Consuming large quantities of the fruit, especially for individuals with some types of kidney disease , can result in serious adverse health effects. The center of diversity and the original range of Averrhoa carambola is tropical Southeast Asia , where it has been cultivated over centuries. It was introduced to the Indian Subcontinent and Sri Lanka by Austronesian traders, along with ancient Austronesian cultigens like langsat , noni , and santol . They remain common in those areas and in East Asia and throughout Oceania and

182-567: A values vary in the literature from 1.25 to 1.46 and from 3.81 to 4.40. The 100th ed of the CRC, released in 2019, has values of 1.25 and 3.81. Oxalic acid is relatively strong compared to other carboxylic acids : Oxalic acid undergoes many of the reactions characteristic for other carboxylic acids. It forms esters such as dimethyl oxalate ( m.p. 52.5 to 53.5 °C, 126.5 to 128.3 °F). It forms an acid chloride called oxalyl chloride . Transition metal oxalate complexes are numerous, e.g.

273-402: A bed of straw, chaff, or mats with windfalls kept separately. Though methods like this will extend the availabity of reasonably fresh apples, without refrigeration their lifespan is limited. Even sturdy winter apple varieties will only keep well until December in cool climates. For longer storage medieval Europeans strung up cored and peeled apples to dry, either whole or sliced into rings. Of

364-407: A blight infection advance. The conjugate base of oxalic acid is the hydrogenoxalate anion, and its conjugate base ( oxalate ) is a competitive inhibitor of the lactate dehydrogenase (LDH) enzyme. LDH catalyses the conversion of pyruvate to lactic acid (end product of the fermentation (anaerobic) process) oxidising the coenzyme NADH to NAD and H concurrently. Restoring NAD levels

455-516: A generic term for all fruit, including nuts . This can be compared to the 14th-century Middle English expression appel of paradis , meaning a banana . The apple is a deciduous tree, generally standing 2 to 4.5 metres (6 to 15 feet) tall in cultivation and up to 15 m (49 ft) in the wild, though more typically 2 to 10 m (6.5 to 33 ft). When cultivated, the size, shape and branch density are determined by rootstock selection and trimming method. Apple trees may naturally have

546-420: A long period of time and permitted secondary introgression of genes from other species into the open-pollinated seeds. Significant exchange with Malus sylvestris , the crabapple, resulted in populations of apples being more related to crabapples than to the more morphologically similar progenitor Malus sieversii . In strains without recent admixture the contribution of the latter predominates. The apple

637-484: A number of organic and non-organic means. In 2010, the fruit's genome was sequenced as part of research on disease control and selective breeding in apple production. The word apple , whose Old English ancestor is æppel , is descended from the Proto-Germanic noun * aplaz , descended in turn from Proto-Indo-European * h₂ébōl . As late as the 17th century, the word also functioned as

728-536: A pantry and four to six weeks from the date of purchase in a refrigerator that maintains 4 to 0 °C (39 to 32 °F). Some varieties of apples (e.g. ' Granny Smith ' and ' Fuji ') have more than three times the storage life of others. Non-organic apples may be sprayed with a substance 1-methylcyclopropene blocking the apples' ethylene receptors, temporarily preventing them from ripening. Apple trees are susceptible to fungal and bacterial diseases, and to damage by insect pests. Many commercial orchards pursue

819-447: A program of chemical sprays to maintain high fruit quality, tree health, and high yields. These prohibit the use of synthetic pesticides, though some older pesticides are allowed. Organic methods include, for instance, introducing its natural predator to reduce the population of a particular pest. A wide range of pests and diseases can affect the plant. Three of the more common diseases or pests are mildew, aphids, and apple scab. Among

910-459: A rounded to erect crown with a dense canopy of leaves. The bark of the trunk is dark gray or gray-brown, but young branches are reddish or dark-brown with a smooth texture. Young twigs are covered in fine downy hairs; they become hairless when older. The buds are egg-shaped and dark red or purple in color; they range in size from 3 to 5 millimeters, but are usually less than 4 mm. The bud scales have very hairy edges. When emerging from

1001-509: A salt from wood sorrel , akin to kraft process . By 1773, François Pierre Savary of Fribourg, Switzerland had isolated oxalic acid from its salt in sorrel. In 1776, Swedish chemists Carl Wilhelm Scheele and Torbern Olof Bergman produced oxalic acid by reacting sugar with concentrated nitric acid ; Scheele called the acid that resulted socker-syra or såcker-syra (sugar acid). By 1784, Scheele had shown that "sugar acid" and oxalic acid from natural sources were identical. The modern name

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1092-427: A short trunk with many branches, reaching up to 9 m (30 ft) in height. Its deciduous leaves are 15–25 cm (6–10 in) long, with 5 to 11 ovate leaflets medium-green in color. Flowers are lilac in color, with purple streaks, and are about 5 mm ( 1 ⁄ 4  in) wide. The showy fruits have a thin, waxy pericarp , orange-yellow skin, and crisp, yellow flesh with juice when ripe. The fruit

1183-454: A solid crystalline compound H 2 C 2 O 4 ·2CO(NH 2 ) 2 , consisting of stacked two-dimensional networks of the neutral molecules held together by hydrogen bonds with the oxygen atoms. At least two pathways exist for the enzyme-mediated formation of oxalate. In one pathway, oxaloacetate , a component of the Krebs citric acid cycle , is hydrolyzed to oxalate and acetic acid by

1274-409: A species has more than 100 alternative scientific names, or synonyms . In modern times, Malus pumila and Malus domestica are the two main names in use. M. pumila is the older name, but M. domestica has become much more commonly used starting in the 21st century, especially in the western world. Two proposals were made to make M. domestica a conserved name : the earlier proposal

1365-560: A strong minority following. Extremely sweet apples with barely any acid flavor are popular in Asia, especially the Indian subcontinent . Old cultivars are often oddly shaped, russeted, and grow in a variety of textures and colors. Some find them to have better flavor than modern cultivars, but they may have other problems that make them commercially unviable—low yield, disease susceptibility, poor tolerance for storage or transport, or just being

1456-452: A tart, sour undertone, and an oxalic acid odor. The taste is difficult to match, but it has been compared to a mix of apple , pear , grape , and citrus family fruits. Unripe star fruits are firmer and sour, and taste like green apples. Ripe carambolas may also be used in cooking. In Southeast Asia, they are usually stewed in cloves and sugar, sometimes with apples . In China, they are cooked with fish. In Australia, they may be cooked as

1547-424: A third reagent in silica analysis instruments. Oxalic acid is used by some beekeepers as a miticide against the parasitic varroa mite . Dilute solutions (0.05–0.15 M ) of oxalic acid can be used to remove iron from clays such as kaolinite to produce light-colored ceramics . Oxalic acid can be used to clean minerals like many other acids. Two such examples are quartz crystals and pyrite. Oxalic acid

1638-528: A vegetable, pickled, or made into jams. In Jamaica they are sometimes dried. Unripe and sour type carambolas can be mixed with other chopped spices to make relishes in Australia. In the Philippines, unripe carambolas are eaten dipped in rock salt . In Thailand, they are cooked together with shrimp. The juice from carambolas is also used in iced drinks, particularly the juice of the sour varieties. In

1729-997: A year. The tree grows rapidly and typically produces fruit at four or five years of age. The large amount of rain during spring actually reduces the amount of fruit, but, in ideal conditions, carambola can produce from 90 to 180 kilograms (200 to 400 pounds) of fruit a year. The carambola tree flowers throughout the year, with main fruiting seasons from April to June and October to December in Malaysia, for example, but fruiting also occurs at other times in some other locales, such as South Florida. Growth and leaf responses of container-grown 'Arkin' carambola ( Averrhoa carambola L.) trees to long-term exposure of 25%, 50%, or 100% sunlight showed that shading increased rachis length and leaflet area, decreased leaflet thickness, and produced more horizontal branch orientation. Major pests are carambola fruit flies , fruit moths, ants, and birds. Crops are also susceptible to frost. Top producers of carambola in

1820-458: Is a neurotoxin which is structurally similar to phenylalanine , and is a glutamatergic agonist. Like the grapefruit , carambola is considered to be a potent inhibitor of seven cytochrome P450 isoforms. These enzymes are significant in the first-pass elimination of many medications, and, thus, the consumption of carambola or its juice in combination with certain prescription medications can significantly increase their effective dosage within

1911-803: Is a round, edible fruit produced by an apple tree ( Malus spp. , among them the domestic or orchard apple ; Malus domestica ). Apple trees are cultivated worldwide and are the most widely grown species in the genus Malus . The tree originated in Central Asia , where its wild ancestor, Malus sieversii , is still found. Apples have been grown for thousands of years in Eurasia and were introduced to North America by European colonists . Apples have religious and mythological significance in many cultures, including Norse , Greek , and European Christian tradition. Apples grown from seed tend to be very different from those of their parents, and

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2002-408: Is about 5 to 15 cm (2 to 6 in) in length and is an oval shape. It usually has five or six prominent longitudinal ridges. In cross-section, it resembles a star. The flesh is translucent and light yellow to yellow in color. Each fruit can have 10 to 12 flat light brown seeds about 5–15 mm ( 1 ⁄ 4 – 1 ⁄ 2  in) in width and enclosed in gelatinous aril . Once removed from

2093-407: Is an organic acid with the systematic name ethanedioic acid and chemical formula HO−C(=O)−C(=O)−OH , also written as (COOH) 2 or (CO 2 H) 2 or H 2 C 2 O 4 . It is the simplest dicarboxylic acid . It is a white crystalline solid that forms a colorless solution in water. Its name comes from the fact that early investigators isolated oxalic acid from flowering plants of

2184-766: Is edible, including the slightly waxy skin. The flesh is crunchy, firm, and extremely juicy. It does not contain fibers and has a texture similar in consistency to that of grapes . Carambolas are best consumed shortly after they ripen when they are yellow with a light shade of green, or just after all traces of green have disappeared. They will also have brown ridges at the edges and feel firm. Fruits picked while still slightly green will turn yellow in storage at room temperature, but will not increase in sugar content. Overripe carambola will be yellow with brown spots and can become blander in taste and soggier in consistency. Ripe sweet type carambolas are sweet without being overwhelming as they rarely have more than 4% sugar content. They have

2275-511: Is essential to the continuation of anaerobic energy metabolism through glycolysis . As cancer cells preferentially use anaerobic metabolism (see Warburg effect ) inhibition of LDH has been shown to inhibit tumor formation and growth, thus is an interesting potential course of cancer treatment. Oxalic acid plays a key role in the interaction between pathogenic fungi and plants. Small amounts of oxalic acid enhances plant resistance to fungi, but higher amounts cause widespread programmed cell death of

2366-482: Is generally considered the center of origin for apples due to the genetic variability in specimens there. The wild ancestor of Malus domestica was Malus sieversii , found growing wild in the mountains of Central Asia in southern Kazakhstan , Kyrgyzstan , Tajikistan , and northwestern China . Cultivation of the species, most likely beginning on the forested flanks of the Tian Shan mountains, progressed over

2457-562: Is generally pale yellowish-white, though it can be pink, yellow or green. Important volatile compounds in apples that contribute to their scent and flavour include acetaldehyde , ethyl acetate , 1-butanal , ethanol , 2-methylbutanal, 3-methylbutanal , ethyl propionate , ethyl 2-methylpropionate, ethyl butyrate , ethyl 2-methyl butyrate, hexanal , 1-butanol , 3-methylbutyl acetate , 2-methylbutyl acetate, 1-propyl butyrate, ethyl pentanoate , amyl acetate , 2-methyl-1-butanol , trans-2-hexenal, ethyl hexanoate , hexanol . The apple as

2548-572: Is hard to distinguish in the archeological record between foraged wild apples and apple plantations. There is indirect evidence of apple cultivation in the third millennium BCE in the Middle East . There is direct evidence, apple cores, dated to the 10th century BCE from a Judean site between the Sinai and Negev. There was substantial apple production in European classical antiquity, and grafting

2639-489: Is quite variable and may be nearly round, elongated, conical, or short and wide. The groundcolor of ripe apples is yellow, green, yellow-green or whitish yellow. The overcolor of ripe apples can be orange-red, pink-red, red, purple-red or brown-red. The overcolor amount can be 0–100%. The skin may be wholly or partly russeted , making it rough and brown. The skin is covered in a protective layer of epicuticular wax . The skin may also be marked with scattered dots. The flesh

2730-419: Is sometimes used in the aluminum anodizing process, with or without sulfuric acid. Compared to sulfuric-acid anodizing, the coatings obtained are thinner and exhibit lower surface roughness. Oxalic acid is also widely used as a wood bleach, most often in its crystalline form to be mixed with water to its proper dilution for use. Oxalic acid is also used in electronic and semiconductor industries. In 2006 it

2821-702: Is the responsibility of the Department of Environment, Food, and Rural Affairs, includes a collection of over 2,000 cultivars of apple tree in Kent. The University of Reading , which is responsible for developing the UK national collection database, provides access to search the national collection. The University of Reading's work is part of the European Cooperative Programme for Plant Genetic Resources of which there are 38 countries participating in

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2912-597: Is thought to have been domesticated 4,000–10,000 years ago in the Tian Shan mountains, and then to have travelled along the Silk Road to Europe, with hybridization and introgression of wild crabapples from Siberia ( M. baccata ), the Caucasus ( M. orientalis ), and Europe ( M. sylvestris ). Only the M. sieversii trees growing on the western side of the Tian Shan mountains contributed genetically to

3003-456: Is used as a cleaning agent, especially for the removal of rust , because it forms a water-soluble ferric iron complex, the ferrioxalate ion. Oxalic acid typically occurs as the dihydrate with the formula H 2 C 2 O 4 ·2H 2 O . The preparation of salts of oxalic acid from plants had been known, at least since 1745, when the Dutch botanist and physician Herman Boerhaave isolated

3094-666: The Pacific Islands . They are cultivated commercially in India , Southeast Asia, southern China , Taiwan , and the southern United States . They are also grown in Central America , South America , and the U.S. state of Hawaii , the Caribbean , and parts of Africa . They are grown as ornamentals . Carambola is considered to be at risk of becoming an invasive species in many world regions. The carambola tree has

3185-460: The apple clearwing moth (red-belted clearwing) burrow through the bark and into the phloem of apple trees, potentially causing significant damage. There are more than 7,500 known cultivars (cultivated varieties) of apples. Cultivars vary in their yield and the ultimate size of the tree, even when grown on the same rootstock . Different cultivars are available for temperate and subtropical climates. The UK's National Fruit Collection, which

3276-598: The hydrogen-bonding results in a chain-like structure, whereas the hydrogen bonding pattern in the other form defines a sheet-like structure. Because the anhydrous material is both acidic and hydrophilic (water seeking), it is used in esterifications . The dihydrate H 2 C 2 O 4 ·2 H 2 O has space group C 2 h – P 2 1 / n , with lattice parameters a = 611.9 pm , b = 360.7 pm , c = 1205.7 pm , β = 106°19′ , Z = 2 . The main inter-atomic distances are: C−C 153 pm, C−O 1 129 pm, C−O 2 119 pm. Oxalic acid's p K

3367-445: The oxides , which is the most commonly marketed form of these elements. Oxalic acid and oxalates can be oxidized by permanganate in an autocatalytic reaction. Oxalic acid vapor decomposes at 125–175 °C into carbon dioxide CO 2 and formic acid HCOOH. Photolysis with 237–313 nm UV light also produces carbon monoxide CO and water. Evaporation of a solution of urea and oxalic acid in 2:1 molar ratio yields

3458-487: The petals are rose-pink and fade to white or light pink when fully open with each flower 3-to-4-centimeter (1-to- 1 + 1 ⁄ 2 -inch) in diameter. The five-petaled flowers are group in an inflorescence consisting of a cyme with 3–7 flowers. The central flower of the inflorescence is called the "king bloom"; it opens first and can develop a larger fruit. Open apple blossoms are damaged by even brief exposures to temperatures −2 °C (28 °F) or less, although

3549-549: The "best" cultivars, showing the proliferation of new North American cultivars by the early 19th century. In the 20th century, irrigation projects in Eastern Washington began and allowed the development of the multibillion-dollar fruit industry, of which the apple is the leading product. Until the 20th century, farmers stored apples in frostproof cellars during the winter for their own use or for sale. Improved transportation of fresh apples by train and road replaced

3640-607: The ' Cosmic Crisp ' cultivar in 2017. The third most grown apple cultivar in the United States is the ' Honeycrisp ', released by the University of Minnesota program in 1991. Unusually for a popular cultivar, the 'Honeycrisp' is not directly related to another popular apple cultivar but instead to two unsuccessful cultivars. In Europe there are also many breeding programs such as the Julius Kühn-Institut ,

3731-815: The 15th century and later went through several cycles of popularity and decline throughout the world. The majority of the rootstocks used to control size in apples were developed in England in the early 1900s. The East Malling Research Station conducted extensive research into rootstocks, and their rootstocks are given an "M" prefix to designate their origin. Rootstocks marked with an "MM" prefix are Malling-series cultivars later crossed with trees of ' Northern Spy ' in Merton, England . Most new apple cultivars originate as seedlings, which either arise by chance or are bred by deliberately crossing cultivars with promising characteristics. The words "seedling", "pippin", and "kernel" in

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3822-590: The German federal research center for cultivated plants. Commercially popular apple cultivars are soft but crisp. Other desirable qualities in modern commercial apple breeding are a colorful skin, absence of russeting , ease of shipping, lengthy storage ability, high yields, disease resistance, common apple shape, and developed flavor. Modern apples are generally sweeter than older cultivars, as popular tastes in apples have varied over time. Most North Americans and Europeans favor sweet, subacid apples, but tart apples have

3913-539: The Malus/Pyrus work group. The UK's national fruit collection database contains much information on the characteristics and origin of many apples, including alternative names for what is essentially the same "genetic" apple cultivar. Most of these cultivars are bred for eating fresh (dessert apples), though some are cultivated specifically for cooking ( cooking apples ) or producing cider . Cider apples are typically too tart and astringent to eat fresh, but they give

4004-802: The Philippines, they can be used as a seasoning. In India, the juice is bottled for drinking. Raw carambola is 91% water, 7% carbohydrates , 1% protein , and has negligible fat (table). A 100-gram reference amount of raw fruit supplies 128 kilojoules (31 kilocalories) of food energy and a rich content of vitamin C (41% of the Daily Value ), with no other micronutrients in significant content (table). Carambolas contain caramboxin and oxalic acid . Both substances are harmful to individuals suffering from kidney failure , kidney stones , or those under kidney dialysis treatment. Consumption by those with kidney failure can produce hiccups , vomiting , nausea , mental confusion, and sometimes death. Caramboxin

4095-737: The United States, carambolas are grown in tropical and semitropical areas, including parts of Florida and Hawaii. In the United States, commercial cultivation and broad consumer acceptance of the fruit only date to the 1970s, attributable to Morris Arkin , a backyard horticulturalist , in Coral Gables, Florida . The 'Arkin' variety represented 98% of the acreage in South Florida in the early 21st century. The trees are also grown as ornamentals for their abundant brightly colored and unusually shaped fruits, as well as for their attractive dark green leaves and their lavender to pink flowers. Like

4186-404: The average 30-day blossom period, with pollinizers selected from cultivars within a 6-day overlap period. There are four to seven pollination groups in apples, depending on climate: One cultivar can be pollinated by a compatible cultivar from the same group or close (A with A, or A with B, but not A with C or D). Cultivars vary in their yield and the ultimate size of the tree, even when grown on

4277-431: The base of the flower. The seeds are egg- to pear-shaped and may be colored from light brown or tan to a very dark brown, often with red shades or even purplish-black. They may have a blunt or sharp point. The five sepals remain attached and stand out from the surface of the apple. The size of the fruit varies widely between cultivars, but generally has a diameter between 2.5 and 12 cm (1 and 5 in). The shape

4368-479: The beverage a rich flavor that dessert apples cannot. In the United States there are many apple breeding programs associated with universities. Cornell University has had a program operating since 1880 in Geneva, New York . Among their recent well known apples is the 'SnapDragon' cultivar released in 2013. In the west Washington State University started a program to support their apple industry in 1994 and released

4459-430: The bilimbi, the juice of the more acidic sour types can be used to clean rusty or tarnished metal (especially brass ) as well as bleach rust stains from cloth. They may also be used as a mordant in dyeing . The farming video game Stardew Valley allows the player to cultivate and grow carambola, in this setting known as "starfruit". They are the most valuable crop in the game. The in-game icon erroneously depicts

4550-561: The body. The carambola is a tropical and subtropical fruit which can be grown at elevations up to 1,200 metres (4,000 feet). It prefers full sun exposure, but requires enough humidity and annual rainfall of at least 1,800 mm (70 in). It does not have a soil type preference, but will thrive in loam and requires good drainage. Moderate irrigation supports its growth during dry seasons. Heavy rains may inhibit fruit production. Carambola trees are planted at least 6 m (20 ft) from each other and typically are fertilized three times

4641-694: The branches. Trees grafted on dwarfing rootstocks bear about 10–80 kg (20–180 lb) of fruit per year. Some farms with apple orchards open them to the public so consumers can pick their own apples. Crops ripen at different times of the year according to the cultivar. Cultivar that yield their crop in the summer include ' Sweet Bough ' and 'Duchess'; fall producers include 'Blenheim'; winter producers include 'King', ' Swayzie ', and 'Tolman Sweet'. Commercially, apples can be stored for months in controlled atmosphere chambers. Apples are commonly stored in chambers with lowered concentrations of oxygen to reduce respiration and slow softening and other changes if

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4732-421: The buds, the leaves are convolute , meaning that their edges overlap each other. Leaves can be simple ovals ( elliptic ), medium or wide in width, somewhat egg-shaped with the wider portion toward their base ( ovate ), or even with sides that are more parallel to each other instead of curved ( oblong ) with a narrow pointed end. The edges have broadly-angled teeth, but do not have lobes. The top surface of

4823-453: The case when a triploid plant can produce a seed (apples are an example), it occurs infrequently, and seedlings rarely survive. Because apples are not true breeders when planted as seeds, propagation usually involves grafting of cuttings. The rootstock used for the bottom of the graft can be selected to produce trees of a large variety of sizes, as well as changing the winter hardiness, insect and disease resistance, and soil preference of

4914-410: The characteristics of the parent. This is because seedling apples are " extreme heterozygotes ". Rather than resembling their parents, seedlings are all different from each other and from their parents. Triploid cultivars have an additional reproductive barrier in that three sets of chromosomes cannot be divided evenly during meiosis, yielding unequal segregation of the chromosomes (aneuploids). Even in

5005-402: The chemical reaction of the carbonate stone with oxalic acid secreted by lichen or other microorganisms . Many soil fungus species secrete oxalic acid, which results in greater solubility of metal cations and increased availability of certain soil nutrients, and can lead to the formation of calcium oxalate crystals. Some fungi such as Aspergillus niger have been extensively studied for

5096-582: The domesticated apple, not the isolated population on the eastern side. Chinese soft apples, such as M. asiatica and M. prunifolia , have been cultivated as dessert apples for more than 2,000 years in China. These are thought to be hybrids between M. baccata and M. sieversii in Kazakhstan. Among the traits selected for by human growers are size, fruit acidity, color, firmness, and soluble sugar. Unusually for domesticated fruits,

5187-465: The drug oxaliplatin . Oxalic acid has been shown to reduce manganese dioxide MnO 2 in manganese ores to allow the leaching of the metal by sulfuric acid . Oxalic acid is an important reagent in lanthanide chemistry. Hydrated lanthanide oxalates form readily in very strongly acidic solutions as a densely crystalline , easily filtered form, largely free of contamination by nonlanthanide elements: Thermal decomposition of these oxalates gives

5278-429: The enzyme oxaloacetase : It also arises from the dehydrogenation of glycolic acid , which is produced by the metabolism of ethylene glycol . Early investigators isolated oxalic acid from wood-sorrel ( Oxalis ). Members of the spinach family and the brassicas ( cabbage , broccoli , brussels sprouts ) are high in oxalates, as are sorrel and umbellifers like parsley . The leaves and stems of all species of

5369-400: The flowering each season, apple growers often utilize pollinators to carry pollen. Honey bees are most commonly used. Orchard mason bees are also used as supplemental pollinators in commercial orchards. Bumblebee queens are sometimes present in orchards, but not usually in sufficient number to be significant pollinators. Cultivars are sometimes classified by the day of peak bloom in

5460-467: The fruit as resembling its real-life cross-section, and the plant itself as a single-harvest crop instead of a tree. The Filipino word for the starfruit, balimbing , due to its many-faced shape, has acquired the meaning in Philippine political discourse of a turncoat , someone who switches political allegiances not out of principle but for their own self-interest. Oxalic acid Oxalic acid

5551-483: The fruit is already fully ripe. The gas ethylene is used by plants as a hormone which promotes ripening, decreasing the time an apple can be stored. For storage longer than about six months the apples are picked earlier, before full ripeness, when ethylene production by the fruit is low. However, in many varieties this increases their sensitivity to carbon dioxide , which also must be controlled. For home storage, most culitvars of apple can be stored for three weeks in

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5642-507: The fruit, they lose viability within a few days. Like the closely related bilimbi , there are two main types of carambola: the small sour (or tart) type and the larger sweet type. The sour varieties have a higher oxalic acid content than the sweet type. A number of cultivars have been developed in recent years. The most common cultivars grown commercially include the sweet types "Arkin" ( Florida ), "Yang Tao" ( Taiwan ), "Ma fueng" ( Thailand ), "Maha" ( Malaysia ), and "Demak" ( Indonesia ) and

5733-455: The genus Chenopodium and related genera of the family Amaranthaceae , which includes quinoa , contain high levels of oxalic acid. Rhubarb leaves contain about 0.5% oxalic acid, and jack-in-the-pulpit ( Arisaema triphyllum ) contains calcium oxalate crystals. Similarly, the Virginia creeper , a common decorative vine, produces oxalic acid in its berries as well as oxalate crystals in

5824-414: The genus Oxalis , commonly known as wood-sorrels. It occurs naturally in many foods. Excessive ingestion of oxalic acid or prolonged skin contact can be dangerous. Oxalic acid has much greater acid strength than acetic acid . It is a reducing agent and its conjugate bases hydrogen oxalate ( HC 2 O − 4 ) and oxalate ( C 2 O 2− 4 ) are chelating agents for metal cations. It

5915-469: The industrial production of oxalic acid; however, those processes are not yet economically competitive with production from oil and gas. Cryphonectria parasitica may excrete oxalic acid containing solutions at the advancing edge of its chestnut cambium infection. The lower pH (<2.5) of more concentrated oxalic acid excretions may degrade cambium cell walls and have a toxic effect on chestnut cambium cells. Cambium cells that burst provide nutrients for

6006-417: The leaves are glabrescent , almost hairless, while the undersides are densely covered in fine hairs. The leaves are attached alternately by short leaf stems 1-to-3.5 cm ( 1 ⁄ 2 -to- 1 + 1 ⁄ 2  in) long. Blossoms are produced in spring simultaneously with the budding of the leaves and are produced on spurs and some long shoots . When the flower buds first begin to open

6097-534: The lethal oral dose is 15 to 30 grams. The toxicity of oxalic acid is due to kidney failure caused by precipitation of solid calcium oxalate . Oxalate is known to cause mitochondrial dysfunction . Ingestion of ethylene glycol results in oxalic acid as a metabolite which can also cause acute kidney failure. Most kidney stones , 76%, are composed of calcium oxalate . ^a Unless otherwise cited, all measurements are based on raw vegetable weights with original moisture content. Apple An apple

6188-689: The many Old World plants that the Spanish introduced to Chiloé Archipelago in the 16th century, apple trees became particularly well adapted. Apples were introduced to North America by colonists in the 17th century, and the first named apple cultivar was introduced in Boston by Reverend William Blaxton in 1640. The only apples native to North America are crab apples . Apple cultivars brought as seed from Europe were spread along Native American trade routes, as well as being cultivated on colonial farms. An 1845 United States apples nursery catalogue sold 350 of

6279-431: The most serious disease problems is a bacterial disease called fireblight , and three fungal diseases: Gymnosporangium rust, black spot , and bitter rot . Codling moths , and the apple maggots of fruit flies, cause serious damage to apple fruits, making them unsaleable. Young apple trees are also prone to mammal pests like mice and deer, which feed on the soft bark of the trees, especially in winter. The larvae of

6370-625: The name of an apple cultivar suggest that it originated as a seedling. Apples can also form bud sports (mutations on a single branch). Some bud sports turn out to be improved strains of the parent cultivar. Some differ sufficiently from the parent tree to be considered new cultivars. Apples have been acclimatized in Ecuador at very high altitudes, where they can often, with the needed factors, provide crops twice per year because of constant temperate conditions year-round. Apples are self-incompatible; they must cross-pollinate to develop fruit. During

6461-458: The necessity for storage. Controlled atmosphere facilities are used to keep apples fresh year-round. Controlled atmosphere facilities use high humidity, low oxygen, and controlled carbon dioxide levels to maintain fruit freshness. They were first researched at Cambridge University in the 1920s and first used in the United States in the 1950s. Many apples grow readily from seeds. However, apples must be propagated asexually to obtain cuttings with

6552-415: The overwintering wood and buds are hardy down to −40 °C (−40 °F). The fruit is a pome that matures in late summer or autumn . The true fruits or carpels are the harder interior chambers inside the apple's core. There are usually five carpels inside an apple, but there may be as few as three. Each of the chambers contains one or two seeds. The edible flesh is formed from the receptacle at

6643-514: The oxalate by mineral acids, such as sulfuric acid . Oxalic acid can also be formed by the heating of sodium formate in the presence of an alkaline catalyst. Although it can be readily purchased, oxalic acid can be prepared in the laboratory by oxidizing sucrose using nitric acid in the presence of a small amount of vanadium pentoxide as a catalyst . The hydrated solid can be dehydrated with heat or by azeotropic distillation . Anhydrous oxalic acid exists as two polymorphs ; in one

6734-486: The pears, apples, and quinces were combined into one genus that he named Pyrus and he named the apple as Pyrus malus . This was widely accepted, however the botanist Philip Miller published an alternate classification in The Gardeners Dictionary with the apple species separated from Pyrus in 1754. He did not clearly indicate that by Malus pumila he meant the domesticated apple. Nonetheless, it

6825-436: The plant and help with fungi infection. Plants normally produce it in small amounts, but some pathogenic fungi such as Sclerotinia sclerotiorum cause a toxic accumulation. Oxalate, besides being biosynthesised, may also be biodegraded. Oxalobacter formigenes is an important gut bacterium that helps animals (including humans) degrade oxalate. Oxalic acid's main applications include cleaning or bleaching, especially for

6916-496: The presence of vanadium pentoxide . A variety of precursors can be used including glycolic acid and ethylene glycol . A newer method entails oxidative carbonylation of alcohols to give the diesters of oxalic acid: These diesters are subsequently hydrolyzed to oxalic acid. Approximately 120,000 tonnes are produced annually. Historically oxalic acid was obtained exclusively by using caustics, such as sodium or potassium hydroxide , on sawdust , followed by acidification of

7007-462: The removal of rust (iron complexing agent). Its utility in rust removal agents is due to its forming a stable, water-soluble salt with ferric iron, ferrioxalate ion. Oxalic acid is an ingredient in some tooth whitening products. About 25% of produced oxalic acid is used as a mordant in dyeing processes. It is also used in bleaches , especially for pulpwood , cork, straw, cane, feathers, and for rust removal and other cleaning, in baking powder, and as

7098-685: The resultant fruit frequently lacks desired characteristics. For commercial purposes, including botanical evaluation, apple cultivars are propagated by clonal grafting onto rootstocks . Apple trees grown without rootstocks tend to be larger and much slower to fruit after planting. Rootstocks are used to control the speed of growth and the size of the resulting tree, allowing for easier harvesting. There are more than 7,500 cultivars of apples . Different cultivars are bred for various tastes and uses, including cooking , eating raw, and cider or apple juice production. Trees and fruit are prone to fungal , bacterial, and pest problems, which can be controlled by

7189-521: The resulting tree. Dwarf rootstocks can be used to produce very small trees (less than 3.0 m or 10 ft high at maturity), which bear fruit many years earlier in their life cycle than full size trees, and are easier to harvest. Dwarf rootstocks for apple trees can be traced as far back as 300 BCE, to the area of Persia and Asia Minor . Alexander the Great sent samples of dwarf apple trees to Aristotle 's Lyceum . Dwarf rootstocks became common by

7280-429: The same rootstock. Some cultivars, if left unpruned, grow very large—letting them bear more fruit, but making harvesting more difficult. Depending on tree density (number of trees planted per unit surface area), mature trees typically bear 40–200 kg (90–440 lb) of apples each year, though productivity can be close to zero in poor years. Apples are harvested using three-point ladders that are designed to fit amongst

7371-549: The sap, in the form of raphides . Bacteria produce oxalates from oxidation of carbohydrates . Plants of the genus Fenestraria produce optical fibers made from crystalline oxalic acid to transmit light to subterranean photosynthetic sites. Carambola , also known as starfruit, also contains oxalic acid along with caramboxin . Citrus juice contains small amounts of oxalic acid. The formation of naturally occurring calcium oxalate patinas on certain limestone and marble statues and monuments has been proposed to be caused by

7462-795: The sour types "Golden Star", "Newcomb", "Star King", and "Thayer" (all from Florida). Some of the sour varieties like "Golden Star" can become sweet if allowed to ripen. Carambola is known by many names across its regions of cultivation, including khế in Vietnam , balimbing in the Philippines , belimbing in Indonesia and Malaysia , ma fen in China , kamaranga in India, and carambolo in Spanish-speaking countries. The entire fruit

7553-594: The wild M. sieversii origin is only slightly smaller than the modern domesticated apple. At the Sammardenchia-Cueis site near Udine in Northeastern Italy, seeds from some form of apples have been found in material carbon dated to between 6570 and 5684 BCE. Genetic analysis has not yet been successfully used to determine whether such ancient apples were wild Malus sylvestris or Malus domesticus containing Malus sieversii ancestry. It

7644-470: The world market include Australia, Guyana , India, Israel , Malaysia , the Philippines, Taiwan, and the United States. Malaysia is a global leader in star fruit production by volume and ships the product widely to Asia and Europe. Due to concerns over pests and pathogens, however, whole star fruits cannot yet be imported to the US from Malaysia under current United States Department of Agriculture regulations. In

7735-433: Was based on the diploid cultivar ' Golden Delicious '. However, this first whole genome sequence contained several errors, in part owing to the high degree of heterozygosity in diploid apples which, in combination with an ancient genome duplication, complicated the assembly. Recently, double- and trihaploid individuals have been sequenced, yielding whole genome sequences of higher quality. The first whole genome assembly

7826-455: Was certainly known then. Grafting is an essential part of modern domesticated apple production, to be able to propagate the best cultivars; it is unclear when apple tree grafting was invented. The Roman writer Pliny the Elder describes a method of storage for apples from his time in the 1st century. He says they should be placed in a room with good air circulation from a north facing window on

7917-469: Was estimated to contain around 57,000 genes, though the more recent genome sequences support estimates between 42,000 and 44,700 protein-coding genes. The availability of whole genome sequences has provided evidence that the wild ancestor of the cultivated apple most likely is Malus sieversii . Re-sequencing of multiple accessions has supported this, while also suggesting extensive introgression from Malus sylvestris following domestication. Central Asia

8008-421: Was introduced along with many other acid names by de Morveau , Lavoisier and coauthors in 1787. In 1824, the German chemist Friedrich Wöhler obtained oxalic acid by reacting cyanogen with ammonia in aqueous solution. This experiment may represent the first synthesis of a natural product . Oxalic acid is mainly manufactured by the oxidation of carbohydrates or glucose using nitric acid or air in

8099-467: Was reported being used in electrochemical–mechanical planarization of copper layers in the semiconductor devices fabrication process. Reduction of carbon dioxide to oxalic acid by various methods, such as electrocatalysis using a copper complex, is under study as a proposed chemical intermediate for carbon capture and utilization . Oxalic acid has an oral LD Lo (lowest published lethal dose) of 600 mg/kg. It has been reported that

8190-639: Was used as such by many botanists. When Moritz Balthasar Borkhausen published his scientific description of the apple in 1803 it may have been a new combination of P. malus var. domestica , but this was not directly referenced by Borkhausen. The earliest use of var. domestica for the apple was by Georg Adolf Suckow in 1786. Apples are diploid , with two sets of chromosomes per cell (though triploid cultivars, with three sets, are not uncommon), have 17 chromosomes and an estimated genome size of approximately 650 Mb. Several whole genome sequences have been completed and made available. The first one in 2010

8281-746: Was voted down by the Committee for Vascular Plants of the IAPT in 2014, but in April 2017 the Committee decided, with a narrow majority, that the newly popular name should be conserved. The General Committee of the IAPT decided in June 2017 to approve this change, officially conserving M. domestica . Nevertheless, some works published after 2017 still use M. pumila as the correct name , under an alternate taxonomy. When first classified by Linnaeus in 1753,

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