Sexual system explained

A sexual system is a distribution of male and female function across organisms in a species.[1] The terms reproductive system and mating system have also been used as synonyms.[2]

Sexual systems are a key factor for genetic variation and reproductive success, and may also have led to the origin or extinction of certain species.[3] The distinctions between different sexual systems is not always clear due to phenotypic plasticity.

Interests in sexual systems go back to Darwin, who found that barnacles contain species that are androdioecious and some that are dioecious.[4]

Types of sexual systems

See also: Plant reproductive morphology. Flowering plants may have dimorphic or monomorphic sexual systems. In monomorphic sexual systems, a combination of hermaphrodite, male, and/or female flowers may be present on the same plant. Monomorphic sexual systems include monoecy, gynomonoecy, andromonoecy, and trimonoecy. In dimorphic sexual systems, individual plants within a species only produce one sort of flower, either hermaphrodite or male, or female. Dimorphic sexual systems include dioecy, gynodioecy, androdioecy, and trioecy.[5]

Male (staminate) flowers have a stamen but no pistil and produce only male gametes. Female (a.k.a. pistillate) flowers only have a pistil. Hermaphrodite (a.k.a. perfect, or bisexual) flowers have both a stamen and pistil. The sex of a single flower may differ from the sex of the whole organism: for example, a plant may have both staminate and pistillate flowers, making the plant as a whole a hermaphrodite. Hence although all monomorphic plants are hermaphrodites, different combinations of flower types (staminate, pistillate, or perfect) produces distinct monomorphic sexual systems.[6]

In animals, androdioecy, gynodioecy, and trioecy are referred to as mixed sexual systems;where hermaphrodites coexist with single sexed individuals.[7]

List of sexual systems

Sexual system Description
males and hermaphrodites coexist in a population. It is rare in both plants and animals.[8]
rare sexual system in angiosperms, in which a plant has both male and hermaphroditic flowers.[9] It has been a subject of interest regarding the mechanism of sex expression.[10]
an individual plant produces either exclusively male or exclusively female flowers at different points in time.[11] It is thought the temporal separation of producing male and female flowers occurs to prevent self-fertilization,[12] however this is debatable as dichogamy occurs in similar frequency among species which are self-compatible and self-incompatible.[13]
one of the main sexual systems in bryophytes.[14] In dioicy male and female sex organs are on separate gametophytes.[15]
a species has distinct individual organisms that are either male or female, i.e., they produce only male or only female gametes, either directly (in animals) or indirectly (in plants).
individuals are either male or female.[16] The term "gonochorism" is usually applied to animals while "dioecy" is applied to plants.[17] Gonochorism is the most common sexual system in animals, occurring in 95% of animal species.[18]
females and hermaphrodites coexist in the same population.[19]
defined as the presence of both female and hermaphrodite flowers on the same individual of a plant species.[20] It is prevalent in Asteraceae but is poorly understood.[21]
Gynodioecy-Gynomonoecy a sexual system for plants when female, hermaphrodite, and gynomonoecious plants coexist in the same population.[22]
one of the main sexual systems in bryophytes. In monoicy male and female sex organs are present in the same gametophyte.
a sexual system in which male and female flowers are present on the same plant. It is common in angiosperms,[23] and occurs in 10% of all plant species.[24]
individuals start their adult lives as one sex, and change to the other sex at a later age.
Sequential monoecy a confusing sexual system,[25] in which the combination of male, female, and hermaphrodite flowers presented changes over time.[26] For example, some conifers produce exclusively either male or female cones when young, then both when older.[27] Sequential monoecy can be difficult to differentiate from dioecy.[28] Several alternative terms may be used in reference to sexual systems involving temporal changes to sex presentation of a plant species (e.g. dichogamy, sequential hermaphroditism, sex change, paradioecy, diphasy).[29]
an individual can produce both gamete types in the same breeding season. Simultaneous hermaphroditism is one of the most common sexual systems in animals (though far less common than gonochorism) and is one of the most stable.[30]
Synoecy all individuals in a population of flowering plants bear solely hermaphrodite flowers.[31]
males, females, and hermaphrodites exist in the same population.[32] It is present in both plants and animals but is always extremely rare. Trioecy occurs in about 3.6% of flowering plants.[33] Trioecy may infrequently be referred to as tridioecy.[34]
(also called androgynomonoecy) is when male, female, and hermaphrodite flowers are present on the same plant.[35] Triomonoecy is rare.[36]

References

Bibliography

Notes and References

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  2. Cardoso. João Custódio Fernandes. Viana. Matheus Lacerda. Matias. Raphael. Furtado. Marco Túlio. Caetano. Ana Paula de Souza. Consolaro. Hélder. Brito. Vinícius Lourenço Garcia de. Jul–Sep 2018. Towards a unified terminology for angiosperm reproductive systems. Acta Botanica Brasilica. en. 32. 3. 329–348. 10.1590/0102-33062018abb0124. 91470660. 0102-3306. free.
  3. Goldberg EE, Otto SP, Vamosi JC, Mayrose I, Sabath N, Ming R, Ashman TL . Macroevolutionary synthesis of flowering plant sexual systems . Evolution; International Journal of Organic Evolution . 71 . 4 . 898–912 . April 2017 . 28085192 . 10.1111/evo.13181 . 19562183 .
  4. Yusa Y, Yoshikawa M, Kitaura J, Kawane M, Ozaki Y, Yamato S, Høeg JT . Adaptive evolution of sexual systems in pedunculate barnacles . Proceedings. Biological Sciences . 279 . 1730 . 959–66 . March 2012 . 21881138 . 3259936 . 10.1098/rspb.2011.1554 .
  5. Torices R, Méndez M, Gómez JM . Where do monomorphic sexual systems fit in the evolution of dioecy? Insights from the largest family of angiosperms . The New Phytologist . 190 . 1 . 234–248 . April 2011 . 21219336 . 10.1111/j.1469-8137.2010.03609.x . free .
  6. Jabbour . Florian . Espinosa . Felipe . Dejonghe . Quentin . Le Péchon . Timothée . 2022-01-07 . Development and Evolution of Unisexual Flowers: A Review . Plants . en . 11 . 2 . 155 . 10.3390/plants11020155 . 35050043 . 8780417 . 2223-7747 . free .
  7. Book: The Evolution of Primary Sexual Characters in Animals . Leonard J, Cordoba-Aguilar A . 2010-07-19 . Oxford University Press, USA . 978-0-19-532555-3 . 29–30 . en.
  8. Book: Pontarotti P . Evolutionary Biology – Concepts, Biodiversity, Macroevolution and Genome Evolution. 2011-07-20. Springer Science & Business Media. 978-3-642-20763-1. 36. en.
  9. Casimiro-Soriguer R, Herrera J, Talavera S . Andromonoecy in an Old World Papilionoid legume, Erophaca baetica . Plant Biology . 15 . 2 . 353–9 . March 2013 . 22823201 . 10.1111/j.1438-8677.2012.00648.x .
  10. Book: Pugnaire F, Valladares F . Functional Plant Ecology. 2007-06-20. CRC Press. 978-1-4200-0762-6. 524. en.
  11. Lloyd . David G. . Webb . C. J. . 1986-07-01 . The avoidance of interference between the presentation of pollen and stigmas in angiosperms I. Dichogamy . New Zealand Journal of Botany . en . 24 . 1 . 135–162 . 10.1080/0028825X.1986.10409725 . 1986NZJB...24..135L . 0028-825X.
  12. Renner . Susanne S. . 2014-10-01 . The relative and absolute frequencies of angiosperm sexual systems: Dioecy, monoecy, gynodioecy, and an updated online database . American Journal of Botany . en . 101 . 10 . 1588–1596 . 10.3732/ajb.1400196. 25326608 . free .
  13. Bertin . Robert I. . Incidence of Monoecy and Dichogamy in Relation to Self-Fertilization in Angiosperms . 1993-05-01 . American Journal of Botany . en . 80 . 5 . 557–560 . 10.1002/j.1537-2197.1993.tb13840.x. 30139145 .
  14. Book: Ramawat KG, Merillon JM, Shivanna KR . Reproductive Biology of Plants. 2016-04-19. CRC Press. 978-1-4822-0133-8. 62. en.
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  16. Book: King RC, Stansfield WD, Mulligan PK . Gonochorism. 2007. https://www.oxfordreference.com/view/10.1093/acref/9780195307610.001.0001/acref-9780195307610-e-2626. A Dictionary of Genetics. Oxford University Press. en. 10.1093/acref/9780195307610.001.0001. 978-0-19-530761-0. 2021-07-28.
  17. Book: Encyclopedia of Evolutionary Biology. 2016-04-14. Academic Press. 978-0-12-800426-5. 2. 212. en.
  18. Leonard JL . Williams' paradox and the role of phenotypic plasticity in sexual systems . Integrative and Comparative Biology . 53 . 4 . 671–88 . October 2013 . 23970358 . 10.1093/icb/ict088 . free .
  19. Book: Fusco G, Minelli A . The Biology of Reproduction. 2019-10-10. Cambridge University Press. 978-1-108-49985-9. 132–133. en.
  20. Book: Allaby M . Gynomonoecious . 2006 . https://www.oxfordreference.com/view/10.1093/acref/9780198608912.001.0001/acref-9780198608912-e-3105. A Dictionary of Plant Sciences . Oxford University Press . 10.1093/acref/9780198608912.001.0001 . 978-0-19-860891-2 .
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  22. Book: Lüttge. Ulrich. Progress in Botany 77. Cánovas. Francisco M.. Matyssek. Rainer. 2016-05-27. Springer. 978-3-319-25688-7. en.
  23. Book: Bahadur B, Sujatha M, Carels N . Jatropha, Challenges for a New Energy Crop: Volume 2: Genetic Improvement and Biotechnology. 2012-12-14. Springer Science & Business Media. 978-1-4614-4915-7. 27–28. en.
  24. Book: Willmer P . Pollination and Floral Ecology. 2011-07-05. Princeton University Press. 978-1-4008-3894-3. 85. en.
  25. Book: Putz. Francis E.. The Biology of Vines. Mooney. Harold A.. 1991. Cambridge University Press. 978-0-521-39250-1. 411. en.
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  27. Kang . Hyesoon . 2007-04-01 . Changes in gender expression in korean populations ofPinus densiflora over a five-year period . Journal of Plant Biology . en . 50 . 2 . 181–189 . 10.1007/BF03030628 . 19890328 . 1867-0725.
  28. Book: Greenwood. Paul J.. Evolution: Essays in Honour of John Maynard Smith. Greenwood. Greenwood, Paul John. Harvey. Paul H.. Harvey. Reader in Biology Department of Zoology Paul H.. Slatkin. Montgomery. Slatkin. Professor of Integrative Biology Montgomery. Cambridge. University of. 1985-07-11. CUP Archive. 978-0-521-25734-3. 240. en.
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  34. Heikrujam . Monika . Sharma . Kuldeep . Prasad . Manoj . Agrawal . Veena . 2015-01-01 . Review on different mechanisms of sex determination and sex-linked molecular markers in dioecious crops: a current update . Euphytica . en . 201 . 2 . 161–194 . 10.1007/s10681-014-1293-z . 254468003 . 1573-5060.
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