Dioicy
Dioicy is a sexual system where archegonia and antheridia are produced on separate gametophytes.[1] It is one of the two main sexual systems in bryophytes. 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.
One biologist [who?] stated there is a good reason for the distinction between dioecy and dioicy. Others have stated that the term dioecy is meaningless for bryophytes.[2]: 62 Nonetheless dioecy and dioicy are comparable in many respects.[3]
Dioicy promotes outcrossing.[4] Dioicy is also heavily connected to the lack of sporophyte production.[5]
Sexual dimorphism is commonly found in dioicous species.[2]: 71 However, according to Bernard Goffinet sexual dimorphism is rare in dioicious moss species.[6]
Etymology
The words dioicous and di(o)ecious are derived from οἶκος or οἰκία and δι- (di-), twice, double. ((o)e is the Latin way of transliterating Greek οι, whereas oi is a more straightforward modern way.) Generally, the term and "dioicous" have been restricted to description of haploid sexuality (gametophytic sexuality), and are thus primarily to describe bryophytes in which the gametophyte is the dominant generation. Meanwhile, "dioecious" are used to describe diploid sexuality (sporophytic sexuality), and thus are used to describe tracheophytes (vascular plants) in which the sporophyte is the dominant generation.[7][8]: 82
Occurrence
68% of liverwort species,[1] 57% to 60%[9] of moss species, and 40% of hornwort species are dioicous.[1] Dioicy is also prevalent in brown algae.[10][clarification needed]
In all cases sex determination is always genetic.[11]
Evolution of dioicy
The ancestral sexual system in bryophytes is unknown but it has been suggested monoicy and dioicy evolved several times.[12] It has also been suggested that dioicy is a plesiomorphic character for bryophytes.[2]: 71
Hornworts have gone through twice as many transitions from dioicy to monoicy than monoicy to dioicy.[1] Sexual specialization has been used as an explanation for the recurring evolution of dioicy in mosses.[2]: 71
In order for dioicy to evolve from monoicy it needs two mutations, a male sterility mutation and a female sterility mutation.[12]
References
- ^ a b c d Villarreal, Juan Carlos; Renner, Susanne S. (2013-11-02). "Correlates of monoicy and dioicy in hornworts, the apparent sister group to vascular plants". BMC Evolutionary Biology. 13 (1): 239. doi:10.1186/1471-2148-13-239. ISSN 1471-2148. PMC 4228369. PMID 24180692.
{{cite journal}}: CS1 maint: unflagged free DOI (link) - ^ a b c d Ramawat KG, Merillon JM, Shivanna KR (2016-04-19). Reproductive Biology of Plants. CRC Press. ISBN 978-1-4822-0133-8.
- ^ Bisang, Irene; Ehrlén, Johan; Hedenäs, Lars (2006). "Reproductive effort and costs of reproduction do not explain female-biased sex ratios in the moss Pseudocalliergon trifarium (Amblystegiaceae)". American Journal of Botany. 93 (9): 1313–1319. doi:10.3732/ajb.93.9.1313. ISSN 1537-2197. PMID 21642196.
- ^ Windsor, Jon and Lesley Lovett-Doust Professor of Biology the University of (1988-07-07). Plant Reproductive Ecology : Patterns and Strategies: Patterns and Strategies. Oxford University Press, USA. pp. 291–292. ISBN 978-0-19-802192-6.
- ^ Windsor, Jon and Lesley Lovett-Doust Professor of Biology the University of (1988-07-07). Plant Reproductive Ecology : Patterns and Strategies: Patterns and Strategies. Oxford University Press, USA. p. 295. ISBN 978-0-19-802192-6.
- ^ Goffinet, Bernard (2008-10-30). Bryophyte Biology. Cambridge University Press. ISBN 978-1-107-37728-8.
- ^ Villarreal, J.C.; Renner, S.S. (2013). "Correlates of monoicy and dioicy in hornworts, the apparent sister group to vascular plants". BMC Evolutionary Biology. 13 (239): 1471–2148. doi:10.1186/1471-2148-13-239. PMC 4228369.
{{cite journal}}: CS1 maint: unflagged free DOI (link) - ^ Buck WR & Goffinet B (2000). "Morphology and classification of mosses". In Shaw AJ & Goffinet B (ed.). Bryophyte Biology. New York: Cambridge University Press. ISBN 978-0-521-66794-4.
- ^ Rensing, Stefan (2016-03-23). Advances in Botanical Research. Vol. 78. Academic Press. p. 109. ISBN 978-0-12-801324-3.
{{cite book}}:|work=ignored (help) - ^ Zhang, Jiaxun; Li, Yan; Luo, Shiju; Cao, Min; Zhang, Linan; Li, Xiaojie (2021-07-14). "Differential gene expression patterns during gametophyte development provide insights into sex differentiation in the dioicous kelp Saccharina japonica". BMC Plant Biology. 21 (1): 335. doi:10.1186/s12870-021-03117-z. ISSN 1471-2229. PMC 8278619. PMID 34261451.
{{cite journal}}: CS1 maint: PMC format (link) CS1 maint: unflagged free DOI (link) - ^ Renner, Susanne S. (2014). "The relative and absolute frequencies of angiosperm sexual systems: Dioecy, monoecy, gynodioecy, and an updated online database". American Journal of Botany. 101 (10): 1588–1596. doi:10.3732/ajb.1400196. ISSN 1537-2197. PMID 25326608.
- ^ a b McDaniel, Stuart F.; Perroud, Pierre-François (2012). "Invited perspective: bryophytes as models for understanding the evolution of sexual systems". The Bryologist. 115 (1): 1–11. doi:10.1639/0007-2745-115.1.1. ISSN 0007-2745. JSTOR 41486736. S2CID 85943617.