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Nightshade

"Nightshade" redirects here. For other uses, see Nightshade (disambiguation).
Solanaceae
A flowering Brugmansia suaveolens
from the US Botanic Garden
Scientific classification
Kingdom: Plantae
(unranked): Angiosperms
(unranked): Eudicots
(unranked): Asterids
Order: Solanales
Family: Solanaceae
Juss.
Subfamilies

Cestroideae
Goetzeoideae
Nicotianoideae
Petunioideae
Schizanthoideae
Schwenckioideae
Solanoideae[1]

The Solanaceae, or nightshades, are an economically important family of flowering plants. The family ranges from herbs to trees, and includes a number of important agricultural crops, medicinal plants, spices, weeds, and ornamentals. Many members of the family contain potent alkaloids, and some are highly toxic, but many cultures eat nightshades, in some cases as a staple food. The family belongs to the order Solanales, in the asterid group dicotyledons (Magnoliopsida).[2] The solanaceae family consists of approximately 98 genera and some 2,700 species,[3] with a great diversity of habitats, morphology and ecology.

The name Solanaceae derives from the genus Solanum "the nightshade plant". The etymology of the Latin word is unclear. The name may come from a perceived resemblance of certain solanaceous flowers to the sun and its rays. In fact one species of Solanum (Solanum nigrum) is known as the "sunberry". Alternatively, the name could originate from the Latin verb solari, meaning "to soothe", presumably referring to the soothing pharmacological properties of some of the psychoactive species of the family.

The family has a worldwide distribution being present on all continents except Antarctica. The greatest diversity in species is found in South America and Central America.

Solanaceae includes a number of commonly collected or cultivated species. Perhaps the most economically important genus of the family is Solanum, which contains the potato (Solanum tuberosum, in fact, another common name of the family is the "potato family"), the tomato (Solanum lycopersicum), and the aubergine or eggplant (Solanum melongena). Another important genus Capsicum produce both chilli peppers and bell peppers.

The genus Physalis produces the so-called groundcherries, as well as the tomatillo (Physalis philadelphica), the Cape gooseberry and the Chinese lantern. The genus Lycium contains the boxthorns and the wolfberry Lycium barbarum. Nicotiana contains, among other species, the plant that produces tobacco. Some other important members of Solanaceae include a number of ornamental plants such as Petunia, Browallia and Lycianthes, the source of psychoactive alkaloids, Datura, Mandragora (mandrake), and Atropa belladonna (deadly nightshade). Certain species are universally known for their medicinal uses, their psychotropic effects or for being poisonous.

With the exception of tobacco (Nicotianoideae) and petunia (Petunioideae), most of the economically important genera are contained in the subfamily Solanoideae. Lastly, but not less importantly, the solanaceas include many model organisms that are important for investigating fundamental biological questions at a cellular, molecular and genetic level, such as tobacco and the petunia.

Description

Solanacea plants are herbaceous plants that can take the form of herbs, shrubs, trees or sometimes vines. They can be annuals, biennials or perennials, upright or decumbent. They can also have subterranean tubers. They do not have laticifers, nor latex, nor coloured saps. They can have a basal or terminal group of leaves or neither of these types. The leaves are generally alternate or alternate to opposed (that is, alternate at the base of the plant and opposed towards the inflorescence). The leaves can be herbaceous, leathery or they can be transformed into spines. The leaves are generally petiolate or sub-sessile, rarely sessile. They are frequently inodorous, but on occasions they are aromatic or fetid. The foliar lamina can be either simple or compound, the latter can be either pinnatifid or ternate. The leaves have reticulate venation and lack a basal meristem. The laminas are generally dorsiventral and lack secretory cavities. The stomata are generally confined to one of a leaf's two sides, they are rarely found on both sides.

The flowers are generally hermaphrodites, although there are some monoecious, andromonoecious or dioecious species (such as for example, some Solanum or Symonanthus). Pollination is entomophilous. The flowers can be solitary or grouped into terminal, cymose or axillary inflorescences. The flowers are medium-sized, fragrant (Nicotiana), fetid (Anthocercis) or inodorous. The flowers are usually actinomorphic, slightly zygomorphic or markedly zygomorphic (such as, for example, in flowers with a bilabial corolla in Schizanthus species). The irregularities in symmetry can be due to the androecium, to the perianth or both at the same time. In the great majority of species the flowers have a differentiated perianth with a calyx and corolla (with 5 sepals and 5 petals respectively) an androecium with 5 stamens and 2 carpels forming a gynoecium with a superior ovary[4] (they are therefore referred to as pentamers and tetracyclic). The stamens are epipetalous and are typically present in multiples of four or five, most commonly four or eight. They usually have a hypogynous disk. The calyx is gamosepalous (as the sepals are joined together forming a tube), with the (4)5(6) segments equal, it has 5 lobes, with the lobes shorter than the tube, it is persistent and it is often accrescent. The corolla usually has 5 petals that are also joined together forming a tube. Flower shapes are typically rotate (wheel-shaped, spreading in one plane, with a short tube) or tubular (elongated cylindrical tube), campanulate or funnel-shaped.

The androecium has (2)(4)5(6) free stamens within it, oppositsepals (that is, they alternate with the petals), they are usually fertile or, in some cases (for example in Salpiglossideae) they have staminodes. In the latter case, there is usually either 1 staminode (Salpiglossis) or 3 (Schizanthus). The anthers touch on their upper end forming a ring, or they are completely free, dorsifixed or basifixed with poricide dehiscence or through small longitudinal cracks. The stamen’s filament can be filliform or flat. The stamens can be inserted inside the coralline tube or exserted. The plants demonstrate simultaneous microsporogenesis, the microspores are tetrad, tetrahedral or isobilateral. The pollen grains are bicellular at the moment of dehiscence, usually open and angular.

The gynoecium is bi-carpelar (rarely 3- or 5-locular) with a superior ovary and 2 locules. The locules may be secondarily divided by false septa, as is the case for Nicandreae and Datureae. The gynoecium is located in an oblique position relative to the flower’s median plane. They have 1 style and 1 stigma, the latter is simple or bilobate. Each locule has 1 to 50 ovules that are anatropous or hemianatropous with axillar placentation. The development of the embryo sack can be the same as for Polygonum or Allium species. The embryo sack’s nuclear poles become fused before fertilization. There are 3 antipodes, usually ephemeral or persistent as in the case of Atropa. The fruit of the solanaceas can be a berry as in the case of the tomato or wolfberry, a dehiscent capsule as in Datura or a drupe. The fruit has axial placentation. The capsules are normally septicidal or rarely loculicidal or valvate. The seeds are usually endospermic, oily (rarely starchy) without obvious hairs. The seeds of most Solanaceae are round and flat, about 2–4 millimetres (0.079–0.157 in) in diameter. The embryo can be straight or curved and has two cotyledons. Most species in the Solanaceae have 2n=24 chromosomes,[5] but the number may be a higher multiple of 12 due to polyploidy. Wild potatoes, of which there are approximately 200, are predominantly diploid (2 × 12 = 24 chromosomes), but triploid (3 × 12 = 36 chromosomes), tetraploid (4 × 12 = 48 chromosomes), pentaploid (5 × 12 = 60) and even hexaploid (6 × 12 = 72 chromosome) species or populations exist. The cultivated species Solanum tuberosum has 4 × 12 = 48 chromosomes. Some Capsicum species have 2 × 12 = 24 chromosomes, while others have 26 chromosomes.

The diversity of some characteristics among the solanaceas

Despite the previous description, the solanaceas exhibit a large morphological variability, even in their reproductive characteristics. Examples of this diversity include:[6][7]

  • The number of carpels that form the gynoecium.

In general all the solanaceas have a gynoecium formed by two carpels. However, there are genera with a monocarpelar gynoecium (Melananthus), or with 3 or 4 carpels such as Capsicum, or with 3 to 5 carpels, such as Nicandra, some species of Jaborosa and Trianaea. Lastly, there is at least one recorded case of a species (Iochroma umbellatum) that possesses a gynoecium with 4 carpels.

  • The number of locules in the ovary

The number of locules in the ovary is usually the same as the number of carpels. However, there are species in which the numbers are not the same due to the existence of false septa (internal walls that subdivide each locule), such as for example in Datura and some members of the Lycieae (the genera Grabowskia and Vassobia).

  • Type of ovules and their number

The ovules of the solanaceas are generally anatropous. However, there are genera with anacampilotropous ovules (for example Phrodus, Grabowskia or Vassobia), hemitropous (Cestrum) or hemicampilotropous (Capsicum, Schizanthus and Lycium). The number of ovules per locule also varies from a few (two pairs in each locule in Grabowskia, one pair in each locule in Lycium) and very occasionally there is only one ovule in each locule as for example in Melananthus.

  • The type of fruit

The great majority of the fruit of the solanaceas are berries or capsules (including pyxidia) and less often drupes. Berries are common in the subfamilies Cestroideae, Solanoideae (with the exception of Datura, Oryctus, Grabowskia and the tribe Hyoscyameae) and the tribe Juanulloideae (with the exception of Markea). Capsules are characteristic of the subfamilies Cestroideae (with the exception of Cestrum) and Schizanthoideae, the tribes Salpiglossoideae, Anthocercidoideae and the genus Datura. The tribe Hyoscyameae has pyxidia. Drupes are typical of the Lycieae tribe and in Iochrominae.

Alkaloids

Alkaloids are nitrogenous organic substances that are produced by plants as a secondary metabolite and which have an intense physiological action on animals even at low doses. Solanaceae are known for having a diverse range of alkaloids. As far as humans are concerned, these alkaloids can be desirable, toxic, or both. The tropanes are the most well known of the alkaloids that are found in the solanaceas. The plants that contain these substances have been used for centuries as poisons. However, despite being recognized as a poison many of these substances have invaluable pharmaceutical properties. The solanaceas are characterized by having many species that contain a variety of alkaloids that are can be more or less active or poisonous, such as scopolamine, atropine, hyoscyamine and nicotine. They are found in plants such as the henbane (Hyoscyamus albus), belladonna (Atropa belladonna), datura or jimson (Datura stramonium), mandrake (Mandragora autumnalis), tobacco and others. Some of the main types of alkaloids found in the solanaceas are:


  • Solanine: toxic glycoalkaloid with a bitter taste that has the formula C45H73NO15. It is formed by the alkaloid solanidine with a carbohydrate side chain. It is found in leaves, fruit and tubers of various solanaceas such as the potato and the tomato. It is thought that its production is an adaptive defence strategy against herbivores. Substance intoxication from solanine is characterized by gastrointestinal disorders (diarrhoea, vomiting, abdominal pain) and neurological disorders (hallucinations and headache). The median lethal dose is between 2 and 5 mg per kilogram of body weight. Symptoms become manifest 8 to 12 hours after ingestion. The amount of these glycoalkaloids in potatoes, for example, varies significantly depending of environmental conditions during their cultivation, the length of storage and the variety. The average glycoalkaloid concentration is 0.075 mg per gram of potato.[8] Solanine has occasionally been responsible for poisonings in people who ate berries from species such as Solanum nigrum or Solanum dulcamara, or green potatoes.[9][10]


  • Tropanes. The term "tropane" comes from a genus in which they are found, Atropa (the belladonna genus). Atropa is named after the Greek Fate, Atropos, who cut the thread of life. This nomenclature reflects its toxicity and lethality. They are bicyclic organic nitrogen compounds (IUPAC nomenclature: 8-Methyl-8-azabicyclo[3.2.1]octane), with the chemical formula of C8H15N. These alkaloids include, among others, atropine and cocaine, scopolamine, and hyoscyamine. They are found in various species of solanaceas, such as for example mandrake (Mandragora autumnalis), black henbane or stinking nightshade (Hyoscyamus niger), belladonna (Atropa belladonna) the stramonium (Datura stramonium) and Brugmansia genera, as well as many others in the Solanaceae family.[11] Pharmacologically, they are the most powerful known anticholinergics in existence, meaning they inhibit the neurological signals transmitted by the endogenous neurotransmitter, acetylcholine. More commonly, they can halt many types of allergic reactions. Symptoms of overdose may include dry mouth, dilated pupils, ataxia, urinary retention, hallucinations, convulsions, coma, and death. Atropine, is a commonly used ophthalmological agent, it dilates the pupils and thus facilitates examination of the interior of the eye. In fact, juice from the berries of Atropa belladonna were used by Italian courtesans during the Renaissance to exaggerate the size of their eyes by causing the dilation of their pupils. Despite the extreme toxicity of the tropanes, they are useful drugs when administered in extremely small dosages. They can reverse cholinergic poisoning, which can be caused by overexposure to organophosphate insecticides and chemical warfare agents such as sarin and VX. Scopolamine (found in Hyoscyamus muticus and Scopolia atropioides), is used as an antiemetic against motion sickness or for people suffering from nausea as a result of receiving chemotherapy.[12][13] Scopolamine and hyoscyamine are the most widely used tropane alkaloids in pharmacology and medicine due to their effects on the parasympathetic nervous system. Atropine has a stimulant effect on the central nervous system and heart, whereas scopolamine has a sedative effect. These alkaloids cannot be substituted by any other class of compounds and for this reason they are still in demand. This is one of the reasons for the development of an active field of research into the metabolism of the alkaloids, the enzymes involved and the genes that produce them. Hyoscyamine 6-β hydroxylase, for example, is the enzyme the catalyses the hydroxylation of hyoscyamine that leads to the production of scopolamine at the end of the tropane’s biosynthetic pathway. This enzyme has been isolated and the corresponding gene cloned from three species: Hyoscyamus niger, Atropa belladonna and Brugmansia candida.[14][15][16]


  • Nicotine. Nicotine (IUPAC nomenclature (S)-3-(1-methylpyrrolidin-2-il) pyridine) is a pyrrolidine alkaloid that is produced in large quantities in the tobacco plant (Nicotiana tabacum), but that is also found in lower concentrations in other solanacea species such as the potato, tomato and pepper. Its function in a plant is to act as a defence against herbivores, as it is an excellent neurotoxin, in particular against insects. In fact, nicotine has been used for many years as an insecticide, although its use is currently being replaced by synthetic molecules derived from its structure. At low concentrations nicotine acts as a stimulant in mammals, which causes the dependency in smokers. Like the tropanes, it acts on cholinergic neurons, but with the opposite effect (it is an agonist as opposed to an antagonist). It has a higher specificity for nicotinic acetylcholine receptors than other ACh proteins.
  • Capsaicin. Capsaicin (IUPAC nomenclature 8-metyl-N-vanillyl-trans-6-nonenamide) is an alkaloid that is structurally different from nicotine and the tropanes. It is found in species of the genus Capsicum, which includes chillies and habanero chillies and it is the active ingredient that determines the Scoville rating of these spices. The compound is not noticeably toxic to humans. However, it stimulates specific pain receptors in the majority of mammals, specifically those related with the perception of heat in the oral mucosa and other epithelial tissues. When capsaicin comes into contact with these mucosa it causes a burning sensation that is little different from a burn caused by real fire. Capsaicin affects only mammals, not birds. Pepper seeds can survive the digestive tract of birds; their fruit becomes brightly coloured once its seeds are mature enough to germinate, thereby attracting the attention of birds that then distribute the seeds. Capsaicin extract is used to make pepper spray, a useful deterrent against aggressive mammals.

Distribution

Even though the solanaceas are found on all the continents except Antarctica the greatest variety of species are found in Central America and South America. Another two centres of diversity include Australia and Africa. The solanaceas occupy a great number of different ecosystems, from deserts to rainforests and they are often found in the secondary vegetation that colonizes disturbed areas.

Taxonomy

The following is a taxonomic synopsis of the solanaceas, including subfamilies, tribes and genera, this is based on the most recent molecular phylogenetics studies of the family.[2][3][17][18]


Cestroideae (sin.:Browallioideae)

  This is a subfamily characterised by the presence of pericyclic fibres, an androecium with 4 or 5 stamens, frequently didynamous. The basic chromosome numbers are highly variable, from x=7 to x=13. The subfamily consists of 8 genera (divided into 3 tribes) and approximately 195 species distributed throughout the Americas. The Cestrum genus is the most important as it contains 175 of the 195 species in the subfamily. The Cestreae tribe is unusual because it includes taxa with long chromosomes (from 7.21 to 11.511 µm in length), when the rest of the family generally possess short chromosomes (for example between 1.5 and 3.52 µm in the Nicotianoideae 
  • Browallieae Tribe Hunz. (1995)
  • Cestreae Tribe Don (1838). Consists of 3 genera of woody plants, generally shrubs.
    • Cestrum L. (1753). Consists of some 175 species distributed throughout the neotropic ecozone.
    • Sessea Ruiz & Pav. (1794). Genus with 16 species from the Andes.
    • Vestia Willd. (1809), monotypic genus from Chile.
  • Salpiglossideae Tribe (Benth.) Hunz. This tribe includes 2 genera and 6 species endemic to Argentina and Chile.
    • Reyesia Gay (1840), consists of 4 species, distributed throughout Argentina and Chile.
    • Salpiglossis Ruiz & Pav. (1794), with 2 species originating from southern South America.

Goetzeoideae

This subfamily is characterized by the presence of drupes as fruit and seeds with curved embryos and large fleshy cotyledons. The basic chromosome number is x=13. It includes 4 genera and 5 species that are distributed throughout the Greater Antilles. Some authors suggest that molecular data indicates that the monotypic genera Tsoala should be included in this subfamily Bosser & D'Arcy (1992), endemic to Madagascar, and Metternichia to the south east of Brazil. Goetzeaceae Airy Shaw is considered as a synonym of this subfamily.[19]

  • Coeloneurum Radlk. (1890), monotypic genus endemic to Hispaniola.
  • Espadaea Rchb. (1850), only contains 1 species from Cuba.
  • Goetzea Wydler (1830), includes 2 species from the Antilles.
  • Henoonia Griseb. (1866), genus with only 1 species originating in Cuba.

Petunioideae

Molecular phylogenetics indicates that Petunioideae is the sister clade of the subfamilies with chromosome number x=12 (Solanoideae and Nicotianoideae). They contain calistegins, alkaloids similar to the tropanes.  The androecium is formed of 4 stamens (rarely 5), usually with two different lengths.  The basic chromosome number of this subfamily can be x=7, 8, 9 and 11. It consists of 13 genera and some 160 species distributed throughout Central and South America. Molecular data suggests that the genera originated in Patagonia Benthamiella, Combera and Pantacantha form a clade that can be categorized as a tribe (Benthamielleae) that  should be in the subfamily Goetzeoideae. 
  • Benthamiella Speg. (1883), includes 12 species native to Patagonia
  • Bouchetia Dunal (1852) with 3 neotropical species.
  • Brunfelsia L. (1753), genus with around 45 species from the neotropics
  • Combera Sandw. (1936), genus with 2 species from Patagonia.
  • Fabiana Ruiz & Pav. (1794), genus that includes 15 species native to the Andes.
  • Hunzikeria D'Arcy (1976), consists of 3 species from the south west of the United States and Mexico.
  • Latua Phil. (1858), contains 1 species from the south of Chile
  • Leptoglossis Benth. (1845), genus with 7 species from the west of South America.
  • Nierembergia Ruiz & Pav. (1794), contains 21 species from South America.
  • Pantacantha Speg. (1902), monospecific genus from Patagonia.
  • Calibrachoa Cerv. ex La Llave & Lex., with 32 species from the neotropics. The morphological data suggests that this genus should be included within the Petunia. However, the molecular and cytogenetic data indicates that both should be kept separate. In fact, Calibrachoa has a basic chromosome number x=9, while that of Petunia is x=7.[20][21]
  • Petunia (Juss.) Wijsman (1803), contains 18 species from South America.
  • Plowmania Hunz. & Subils (1986), monotypic genus from Mexico and Guatemala.

Schizanthoideae

Includes annual and biannual plants with tropane alkaloids, without pericyclic fibres, with characteristic hair and pollen grains. The flowers are zygomorphic. The androecium has 2 stamen and 3 stamenodes, anther dehiscence is explosive. The embryo is curved. The basic chromosome number is x=10. Schizanthus is a somewhat atypical genus among the solanaceas due to its strongly zygomorphic flowers and basic chromosome number. Morphological and molecular data suggest that Schizanthus is a sister genus to the other solanaceas and diverged early from the rest of the solanaceas, probably in the late Cretaceous or in the early Cenozoic, 50 million years ago.[17][18] The great diversity of flower types within Schizanthus has been the product of the species’ adaptation to the different types of pollinator that exist in the Mediterranean, high alpine and desert ecosystems that were present in Chile and adjacent areas of Argentina.[22]
  • Schizanthus Ruiz et Pav. (1794), contains 12 species originating from Chile.

Schwenckioideae

Contains annual plants with pericyclic fibres, the flowers are zygomorphic, the androecium has 4 didynamous stamens or 3 stamenodes, the embryo is straight and short. El basic chromosome number is x=12. Includes 4 genera and some 30 species distributed throughout South America.

  • Heteranthia Nees & Mart. (1823), 1 species from Brazil.
  • Melananthus Walp. (1850), includes 5 species from Brazil, Cuba and Guatemala.
  • Protoschwenckia Soler (1898), monotypic genus from Bolivia and Brazil. Some molecular phylogenetic studies have suggested that this genus has an uncertain taxonomic position within the subfamily.
  • Schwenckia L. (1764), contains 22 species distributed throughout the neotropical regions of America.

Nicotianoideae


  • Anthocercideae Tribe G.Don (1838). This tribe is endemic to Australia and contains 31 species distributed in 7 genera. Molecular phylogenetic studies of the tribe indicate that it is the sister of Nicotiana, that the genera Anthocercis, Anthotroche, Grammosolen and Symonanthus are monophyletic, Some characteristics are also thought to be derived from within the tribe, such as the unilocular stamens with semi-circular opercula, bracteolate flowers and berries as fruit.[23]
    • Anthocercis Labill. (1806), 10 species, Australia
    • Anthotroche Endl. (1839), 4 species, Australia
    • Crenidium Haegi (1981), monotypic genus, Australia
    • Cyphanthera Miers (1853), 9 species, Australia
    • Duboisia R.Br. (1810), 4 species, Australia
    • Gramnosolen Haegi (1981), 2 species, Australia
    • Symonanthus Haegi (1981), 2 species, Australia
  • Nicotianeae Tribe Dum. (1827)
    • Nicotiana L. (1754), genus widely distributed, with 52 American species, 23 Australian and one African.

Solanoideae


  • Capsiceae Tribe Dumort (1827)
    • Capsicum L. (1753), genus that includes some 31 neotropical species.
    • Lycianthus (Dunal) Hassler (1917), with some 200 species distributed throughout America and Asia.
  • Datureae Tribe G. Don (1838) this tribe has 2 genera that are perfectly differentiated at both a morphological and molecular level. Brugmansia includes tree species, while Datura contains herbs or shrubs. The latter genus can be divided into 3 sections: Stramonium, Dutra and Ceratocaulis.[24]
    • Brugmansia Persoon (1805), genus that includes 6 species from the Andes. (incl.: Methysticodendron Schult. (1955))
    • Datura L. (1753), with 11 neotropical species.
  • Hyoscyameae Tribe Endl. (1839)
    • Anisodus Link (1825), with 4 species from China, India and the Himalayas.
    • Atropa L. (1753), contains 3 euro Asiatic species.
    • Atropanthe Pascher (1909), monotypic genus from China.
    • Hyoscyamus L. (1753), contains around 20 species distributed from the Mediterranean to China.
    • Physochlaina G. Don (1838), includes 11 euro Asiatic species.
    • Przewalskia Maxim. (1881) with just 1 species from China.
    • Scopolia Jacq. (1764), genus with a disjointed distribution with 1 European species and another from Japan.
  • Jaboroseae Tribe Miers (1849)
    • Jaborosa Juss. (1789), genus that includes 23 species from South America.
  • Solandreae Tribe Miers (1849)
    • Subtribe Juanulloinae: consists 10 genera of trees and epiphytic shrubs with a neotropical distribution .[25] Some of these genera (Dyssochroma, Merinthopodium and Trianaea) show a clear dependency on various species of bat both for pollination and for the dispersion of seeds.[26]
      • Dyssochroma Miers (1849), with 2 species from the south of Brazil.
      • Ectozoma Miers (1849)
      • Hawkesiophyton Hunz. (1977)
      • Juanulloa Ruiz et Pav. (1794), with 11 species from South and Central America.
      • Markea Rich.(1792) genus that contains 9 species from South and Central America.
      • Merinthopodium J. Donn. Sm. (1897) including 3 species originating from South America.
      • Rahowardiana D' Arcy (1973)
      • Schultesianthus Hunz. (1977), genus that includes 8 neotropical species.
      • Trianaea Planch. et Linden (1853) with 6 South American species.
    • Subtribe Solandrinae, is a monotypical subtribe that differs from Juanulloinae in that its embryos have incumbent cotyledons and a semi-inferior ovary.[25]
    • Solandra Sw. (1787), includes 10 species from the neotropical regions of America.
  • Lycieae Tribe Hunz. (1977), comprising 3 genera of woody plants that grow in arid or semiarid climates. The cosmopolitan genus 'Lycium is the oldest in the tribe and it has the greatest morphological variability.[27] Molecular phylogenetic studies suggest that both Grabowskia and Phrodus should be included in the Lycium[28] and that this genus along with Nolana and Sclerophylax form a clade (Lyciina), which currently lacks a taxonomic category.[19] The red fleshy berries are dispersed by birds, this is the main type of fruit in Lycium. The different types of fruit in this genus have evolved from the type of berry just mentioned to a drupe with a reduced number of seeds.[29]
    • Grabowskia Schltdl. (1832), 3 species from South America.
    • Lycium L. (1753), cosmopolitan, includes 83 species.
    • Phrodus Miers (1849), endemic to the north of Chile, includes 2 species.
  • Tribe Mandragoreae (Wettst.) Hunz. & Barboza (1995). This monotypic tribe does not have a defined systematic position according to molecular phylogenetic studies.[19]
  • Tribe Nicandreae Wettst. (1891), is a tribe with 2 South American genera. Molecular phylogenetic studies indicate that the genera are not interrelated nor are they related with other genera of the family, so their taxonomic position is uncertain.[19]
    • Exodeconus Raf. (1838), with 6 species from the west of South America.
    • Nicandra Adans (1763), genus with just 1 species distributed throughout neotropical regions.
  • Tribe Nolaneae Rchb. (1837)
    • Nolana L. (1762) are mostly herbs and small shrubs with succulent leaves, they have very beautiful flowers that range from white to various shades of blue, their fruit is schizocarpal giving rise to various nuts. The genus has 89 species distributed throughout the west of South America.
  • Tribe Physaleae Miers (1849), is a large tribe that is the sister of Capsiceae.
    • Subtribe Iochrominae (Miers) Hunz. is a clade within the Physaleae tribe that contains 37 species, mainly distributed in the Andes, assigned to 6 genera. The members of this subtribe are characterized by being woody shrubs or small trees with attractive tubular or rotated flowers. They also posses a great floral diversity, containing every type that is present in the family. Its flowers can be red, orange, yellow, greed, blue, purple or white. The corolla can be tubular to rotated, with a variation of up to 8 times in the length of the tube between the various species.[30]
      • Acnistus Schott (1829), with 1 species distributed throughout the neotropics.
      • Dunalia Kunth. (1818), includes 5 species from the Andes.
      • Iochroma Benth. (1845), genus with 24 species from the Andes.
      • Saracha Ruiz et Pav. (1794), includes 2 species from the Andes.
      • Vassobia Rusby (1927), with 2 South American species.
      • Eriolarynx Hunz.(2000), genus that contains 3 species from Argentina and Bolivia.
    • Subtribe Physalinae (Miers) Hunz. (2000). Is a monophyletic subtribe that contains 10 genera and includes herbs or woody shrubs with solitary axillary flowers that are yellow, white or purple and that are pollinated by bees. Once pollination occurs the corolla falls and the calyx expands until it entirely covers the boll that is developing (the calyx is called accrescent). In many species the calyx turns yellow or orange on maturity. The berries contain many seeds they are greenish to yellow-orange, often with red or purple highlights.[31]
      • Brachistus Miers (1849), with 3 species from Mexico and Central America.
      • Chamaesaracha (A.Gray) Benth. et Hook. (1896), has 10 species from Mexico and Central America.
      • Leucophysalis Rydberg (1896), includes 3 species from the south west of the United States and Mexico.
      • Margaranthus Schlecht. (1830), with 1 species from Mexico.
      • Oryctes S. Watson (1871), monotypic genus from the south west of the United States.
      • Quincula Raf. (1832) with just 1 species from the south west of the United States and from Mexico.
      • Physalis L. (1753), the largest genus of the subtribe, with 85 species distributed through the tropical regions of the Americas and with 1 species in China.
      • Witheringia L' Heritier (1788), genus with 15 species from neotropical regions.
      • Tzeltalia, genus segregated from Physalis, with 2 species distributed throughout Mexico and Guatemala.
      • Darcyanthus, genus with just 1 specie originating in Bolivia and Peru.
    • Subtribe Salpichroinae, this is a subtribe of Physaleae that includes 16 American species distributed in 1 genera:
      • Nectouxia Kunth. (1818), monotypic genus that is endemic to Mexico.
      • Salpichroa Miers (1845), genus with 15 species from the Andes and other regions of South America.
    • Subtribe Withaninae, is a subtribe of Physaleae with a broad distribution, including 9 genera:
      • Archiphysalis Kuang (1966), with 3 species from China and Japan.
      • Athenaea Sendtn. (1846), which includes 7 species from Brazil.
      • Aureliana Sendt. (1846), with 5 species from South America.
      • Melissia Hook. f. (1867), monotypic genus from Santa Elena with the common name St. Elena boxwood.
      • Physalisastrum Makino (1914), with 9 Asiatic species.
      • Tubocapsicum (Wettst.) Makino (1908), with just one species endemic to China.
      • Withania Pauq.(1825), with 10 species native to the Canary Islands, Africa and Nepal.
      • Cuatresia Hunz. (1977), with 11 neotropical species. Molecular studies indicate that this genus, along with Deprea and Larnax has an uncertain taxonomic position.[19]
      • Deprea Raf. (1838), with 6 neotropical species.
      • Larnax Miers (1849), many taxonomists consider it to be a synonym for Deprea, contains 22 species native to the Andes.
  • Tribe Solaneae (1852). The genera Cyphomandra Sendtn. (1845), Discopodium Hochst. (1844), Normania Lowe (1872), Triguera Cav. (1786) and Lycopersicum Mill have been transferred to Solanum. The subtribe is therefore composed of two genera:[19]
      • Jaltomata Schltdl. (1838), which contains 50 neotropical species.
      • Solanum L. (1753), the largest genus in the family and one of the broadest of the angiosperms, with 1,328 species distributed across the whole world.
  • Genera with doubtful taxonomic positions (Incertae sedis)

The following genera have still not been placed in any of the recognized subfamilies within the solanaceas.

  • Duckeodendron Kuhlmannb (1925), monospecific genus from the Amazon rainforest.
  • Parabouchetia Baillon (1888)
  • Pauia Deb. & Dutta (1965)

Genera and distribution of species


The solanaceas contain 98 genera and some 2,700 species. Despite this immense richness of species they are not uniformly distributed between the genera. The 8 most important genera contain more than 60% of the species, as shown in the table below. In fact, just Solanum – the genus that typifies the family- includes nearly 50% of the total species of the solanaceas.

Genera Approximate number of species
Solanum 1,330
Lycianthes 200
Cestrum 150
Nolana 89
Physalis 85
Lycium 85
Nicotiana 76
Brunfelsia 45
Estimated number of species in the family 2,700

Economic importance


The solanaceas include such important food species as the potato (Solanum tuberosum), the tomato (Solanum lycopersicum), the pepper (Capsicum annuum) and the aubergine or egg plant (Solanum melongena). Nicotiana tabacum, originally from South America, is now cultivated throughout the world to produce tobacco. Many solanaceas are important weeds in various parts of the world. Their importance lies in the fact that they can host pathogens or diseases of the cultivated plants, therefore their presence increases the loss of yield or the quality of the harvested product. An example of this can be seen with Acnistus arborescens and Browalia americana that host thrips, which cause damage to associated cultivated plants,[32] and certain species of Datura that play host to various types of virus that are later transmitted to cultivated solanaceas.[33] Some species of weeds such as, for example Solanum mauritianum in South Africa represent such serious ecological and economic problems that studies are being carried out with the objective of developing a biological control through the use of insects.[34]

Various solanaceas species are grown as ornamental trees or shrubs.[35] Examples include Brugmansia x candida ("Angel’s Trumpet") grown for its large pendulous trumpet-shaped flowers, or Brunfelsia latifolia, whose flowers are very fragrant and change colour from violet to white over a period of 3 days. Other shrub species that are grown for their attractive flowers are Lycianthes rantonnetii (Blue Potato Bush or Paraguay Nightshade) with violet-blue flowers and Nicotiana glauca ("Tree Tobacco") Other solanacea species and genera that are grown as ornamentals are the petunia (Petunia × hybrida), Lycium, Solanum, Cestrum, Calibrachoa × hybrida and Solandra. There is even a hybrid between Petunia and Calibrachoa (which constitutes a new nothogenus called × Petchoa G. Boker & J. Shaw) that is being sold as an ornamental.[36][37] Many other species, in particular those that produce alkaloids, are used in pharmacology and medicine (Nicotiana, Hyoscyamus, and Datura).

Solanaceas and the genome

Many of the species belonging to this family, among them tobacco and the tomato, are model organisms that are used for research into fundamental biological questions. One of the aspects of the solanaceas’ genomics is an international project that is trying to understand how the same collection of genes and proteins can give rise to a group of organisms that are so morphologically and ecologically different. The first objective of this project was to sequence the genome of the tomato. In order to achieve this each of the 12 chromosomes of the tomato’s haploid genome was assigned to different sequencing centres in different countries. So chromosomes 1 and 10 were sequenced in the United States, 3 and 11 in China, 2 in Korea, 4 in Britain, 5 in India, 7 in France, 8 in Japan, 9 in Spain and 12 in Italy. The sequencing of the mitochondrial genome was carried out in Argentina and the chloroplast genome was sequenced in the European Union.[38][39]

See also

References

  • Dimitri, M. 1987. Enciclopedia Argentina de Agricultura y Jardinería. Tomo I. Descripción de plantas cultivadas. Editorial ACME S.A.C.I., Buenos Aires.
  • Hunziker, Armando T. 2001. The Genera of Solanaceae. A.R.G. Gantner Verlag K.G., Ruggell, Liechtenstein. ISBN 3-904144-77-4.

Further reading

External links

  • Sol Genomics Network
  • Solanaceae Network - pictures of plants
  • Solanaceae Source - A worldwide taxonomic monograph of all species in the genus Solanum.
  • Solanaceae of Chile, by Chileflora
  • http://delta-intkey.com
  • Solanaceae in USDA Plants Database.
  • Family Solanaceae Flowers in Israel
  • , Universidad de Cornell
  • Imagines de various species of Solanaceae
  • Solanaceae de Chile, by Chileflora
  • , site with abundant information regarding Solanaceas
  • Chilli: La especia del Nuevo Mundo (Article in Spanish by Germán Octavio López Riquelme regarding the biology, nutrition, culture and medical aspects of Chile.

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