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Gynodioecious
Gynodioecy is a rare breeding system that is found in certain flowering plant species in which female and hermaphroditic plants coexist within a population. Gynodioecy is the evolutionary intermediate between hermaphroditism (exhibiting both female and male parts) and dioecy (having two distinct morphs: male and female). Gynodioecy is sometimes considered a mixed breeding system alongside trioecy and androdioecy. It is also considered a dimorphic sexual system alongside dioecy and androdioecy. Gynodioecy occurs as a result of a genetic mutation that inhibits a hermaphroditic plant from producing pollen, while keeping the female reproductive parts intact. Gynodioecy is extremely rare, with fewer than 1% of angiosperm species exhibiting the breeding system. Some notable taxa that exhibit a gynodioecious mating system include ''Beta vulgaris'' (wild beet), ''Lobelia siphilitica'', ''Silene'', and Lamiaceae. Evolution Gynodioecy is often referred to as the evolutionary intermedi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sex Determination In Silene
''Silene'' is a flowering plant genus that has evolved a dioecious reproductive system. This is made possible through heteromorphic sex chromosomes expressed as XY. ''Silene'' recently evolved sex chromosomes 5-10 million years ago and are widely used by geneticists and biologists to study the mechanisms of sex determination since they are one of only 39 species across 14 families of angiosperm that possess sex-determining genes. ''Silene'' are studied because of their ability to produce offspring with a plethora of reproductive systems. The common inference drawn from such studies is that the sex of the offspring is determined by the Y chromosome. Evolution of Sex Chromosomes Biologists have found that sex chromosomes in plants originated from pairs of autosomes. As these chromosomes diverge from their autosomal ancestor and from each other as a homologous pair, they have the potential to increase or decrease in size due to mutation and recombination. In the case of ''Sile ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silene
''Silene'' is a genus of flowering plants in the family Caryophyllaceae. Containing nearly 900 species, it is the largest genus in the family. Common names include campion and catchfly. Many ''Silene'' species are widely distributed, particularly in the northern hemisphere. Scientific history Members of this genus have been the subject of research by preeminent plant ecologists, evolutionary biologists, and geneticists, including Charles Darwin, Gregor Mendel, Carl Correns, Herbert G. Baker, and Janis Antonovics. Many ''Silene'' species continue to be widely used to study systems, particularly in the fields of ecology and evolutionary biology.Bernasconi et al. 2009. Silene as a model system in ecology and evolution. Heredity. 103:5-14. PMI19367316/ref> The genus has been used as a model for understanding the genetics of sex determination for over a century. ''Silene'' species commonly contain a mixture of hermaphroditic and female (or male-sterile) individuals (gynodioecy), and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Self-incompatible
Self-incompatibility (SI) is a general name for several genetic mechanisms that prevent self-fertilization in sexually reproducing organisms, and thus encourage outcrossing and allogamy. It is contrasted with separation of sexes among individuals (dioecy), and their various modes of spatial (herkogamy) and temporally (dichogamy) separation. SI is best-studied and particularly common in flowering plants, although it is present in other groups, including sea squirts and fungi. In plants with SI, when a pollen grain produced in a plant reaches a stigma of the same plant or another plant with a matching allele or genotype, the process of pollen germination, pollen-tube growth, ovule fertilization, or embryo development is inhibited, and consequently no seeds are produced. SI is one of the most important means of preventing inbreeding and promoting the generation of new genotypes in plants and it is considered one of the causes of the spread and success of angiosperms on Earth. Mechan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cucurbita Foetidissima
''Cucurbita foetidissima'' is a tuberous xerophytic plant found in the central and southwestern United States and northern Mexico. It has numerous common names, including: buffalo gourd, calabazilla, chilicote, coyote gourd, fetid gourd, fetid wild pumpkin, Missouri gourd, prairie gourd, stinking gourd, wild gourd, and wild pumpkin. The type specimen was collected from Mexico by Alexander von Humboldt and Aimé Bonpland sometime before 1817. In Latin, foetidissima means ill smelling. The buffalo gourd has evolved in the semiarid regions and is well-adapted to desert environments. It contains high amounts of protein and carbohydrates and yields abundant oil. The carbohydrates that are formed in the tap root have led to the idea of growing the plant for biofuel. The fruit is consumed by both humans and animals. When mature, a stage marked by increasing desiccation of vine, leaves, fruit-stem, and fruit, the fruit begins its final gourd stage. Geographic location and genetics make ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monoicous
Monoicy () is a sexual system in haploid plants (mainly bryophytes) where both sperm and eggs are produced on the same gametophyte, in contrast with dioicy, where each gametophyte produces only sperm or eggs but never both.Crandall-Stotler, B.J. & Bartholomew-Began, S.E. (2007). ''Morphology of Mosses (Phylum Bryophyta)''. In: Flora of North America Editorial Committee, eds. (1993+). ''Flora of North America North of Mexico''. 16+ vols. New York and Oxford. Volume 27, 2007.Bell, P.R. & Helmsley, A.R. (2000). ''Green plants, their origin and diversity'' (2nd ed.). Cambridge University Press. Both monoicous () and dioicous gametophytes produce gametes in gametangia by mitosis rather than meiosis, so that sperm and eggs are genetically identical with their parent gametophyte. It has been suggested that monoicy may have benefits in dry habitats where the ability to produce sporophytes is limited due to lack of water. Monoicy is similar to, and often conflated with, monoecy, wh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hermaphrodite
In reproductive biology, a hermaphrodite () is an organism that has both kinds of reproductive organs and can produce both gametes associated with male and female sexes. Many Taxonomy (biology), taxonomic groups of animals (mostly invertebrates) do not have separate sexes. In these groups, hermaphroditism is a normal condition, enabling a form of sexual reproduction in which either partner can act as the female or male. For example, the great majority of tunicata, tunicates, pulmonate molluscs, opisthobranch, earthworms, and slugs are hermaphrodites. Hermaphroditism is also found in some fish species and to a lesser degree in other vertebrates. Most plants are also hermaphrodites. Animal species having different sexes, male and female, are called Gonochorism, gonochoric, which is the opposite of hermaphrodite. There are also species where hermaphrodites exist alongside males (called androdioecy) or alongside females (called gynodioecy), or all three exist in the same species ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Androdioecy
Androdioecy is a reproductive system characterized by the coexistence of males and hermaphrodites. Androdioecy is rare in comparison with the other major reproductive systems: dioecy, gynodioecy and hermaphroditism. In animals, androdioecy has been considered a stepping stone in the transition from dioecy to hermaphroditism, and vice versa. Androdioecy is sometimes referred to as a mixed breeding system with trioecy and gynodioecy. It is a dimorphic sexual system in plants alongside gynodioecy and dioecy. Evolution of androdioecy The fitness requirements for androdioecy to arise and sustain itself are theoretically so improbable that it was long considered that such systems do not exist. Particularly, males and hermaphrodites have to have the same fitness, in other words the same number of offspring, in order to be maintained. However, males only have offspring by fertilizing eggs or ovules of hermaphrodites, while hermaphrodites have offspring both through fertilizing eggs or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trioecy
Trioecy, or subdioecy, is a rare sexual system characterized by the coexistence of males, females, and hermaphrodites. It has been found in both plants and animals. Trioecy is sometimes referred to as a mixed mating system alongside androdioecy and gynodioecy. Evolution of trioecy Many speculate trioecy is a transient state and is often associated with evolutionary transitioning from gynodioecy to dioecy. Other studies show that trioecious populations originated from gonochoristic ancestors which were invaded by a mutant selfing hermaphrodite, creating a trioecious population. It has been suggested that chromosomal duplication is an important part in the evolution of trioecy. Evolutionary stability Trioecy is usually viewed as evolutionarily unstable, but its exact stability is unclear. Like in brachiopod species trioecy usually breaks into androdioecy or gynodioecy. But one study found that trioecy can be stable under nucleocytoplasmic sex determination. Another theoretical ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dioecy
Dioecy (; ; adj. dioecious , ) is a characteristic of a species, meaning that it has distinct individual organisms (unisexual) that produce male or female gametes, either directly (in animals) or indirectly (in seed plants). Dioecious reproduction is biparental reproduction. Dioecy has costs, since only about half the population directly produces offspring. It is one method for excluding self-fertilization and promoting allogamy (outcrossing), and thus tends to reduce the expression of recessive deleterious mutations present in a population. Plants have several other methods of preventing self-fertilization including, for example, dichogamy, herkogamy, and self-incompatibility. Dioecy is a dimorphic sexual system, alongside gynodioecy and androdioecy. In zoology In zoology, dioecious species may be opposed to hermaphroditic species, meaning that an individual is either male or female, in which case the synonym gonochory is more often used. Most animal species are dioecious (gon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Erythranthe Guttata
''Erythranthe guttata'', with the common names seep monkeyflower and common yellow monkeyflower, is a yellow bee-pollinated annual or perennial plant. It was formerly known as ''Mimulus guttatus''. ''Erythranthe guttata'' is a model organism for biological studies, and in that context is still referred to as ''Mimulus guttatus''. There may be as many as 1000 scientific papers focused on this species. The genome is (as of 2012) being studied in depth. Description A highly variable plant, taking many forms, ''E. guttata'' is a species complex in that there is room to treat some of its forms as different species by some definitions. The plant ranges from tall with disproportionately large, 2 to 4 cm long, tubular flowers. The perennial form spreads with stolons or rhizomes. The stem may be erect or recumbent. In the latter form, roots may develop at leaf nodes. Sometimes dwarfed, it may be hairless or have some hairs. Leaves are opposite, round to oval, usually coarsely an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reynoutria Japonica
''Reynoutria japonica'', synonyms ''Fallopia japonica'' and ''Polygonum cuspidatum'', is a species of herbaceous perennial plant in the knotweed and buckwheat family Polygonaceae. Common names include Japanese knotweed and Asian knotweed. It is native to East Asia in Japan, China and Korea. In North America and Europe, the species has successfully established itself in numerous habitats, and is classified as a pest and invasive species in several countries. Japanese knotweed has hollow stems with distinct raised nodes that give it the appearance of bamboo, though it is not related. While stems may reach a maximum height of each growing season, it is typical to see much smaller plants in places where they sprout through cracks in the pavement or are repeatedly cut down. The leaves are broad oval with a truncated base, long and broad, with an entire margin. The flowers are small, cream or white, produced in erect racemes long in late summer and early autumn. Related species ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
True Plantain
"True" plantains are a group of cultivars of the genus ''Musa'' ( bananas and plantains) placed in the African Plantain subgroup of the AAB chromsome group. Although "AAB" and "true plantain" are often used interchangeably, plantains are just the most popular varieties among the AABs. The term "plantain" can refer to all the banana cultivars which are normally eaten after cooking, rather than raw (see cooking banana), or it can refer to members of other subgroups of ''Musa'' cultivars, such as the Pacific plantains, although in Africa there is little to no distinction made between the two, as both are commonly cooked. True plantains are divided into four groups based on their bunch type: French, French Horn, False Horn, and Horn plantains. Each bunch type has a variety of cultivars associated with it: * French cultivars: 'Obino l'Ewai' (Nigeria), 'Nendran' (India), 'Dominico' (Colombia) * French Horn cultivars: 'Batard' (Cameroon), 'Mbang Okon' (Nigeria) * False Horn cultivars: ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
