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Annual Reproductive Cycle and Unusual Embryogenesis of a Temperate Coral in the Mediterranean Sea.

Marchini C, Airi V, Fontana R, Tortorelli G, Rocchi M, Falini G, Levy O, Dubinsky Z, Goffredo S - PLoS ONE (2015)

Bottom Line: Not only females, but also sexually inactive individuals (without germ cells) and males were found to brood their embryos.Gametogenesis showed a strong seasonal influence, while embryos were found throughout the year in males and in sexually inactive individuals without a defined trend.This unusual embryogenesis suggests the possibility of agamic reproduction, which combined with sexual reproduction results in high fertility.

View Article: PubMed Central - PubMed

Affiliation: Marine Science Group, Department of Biological, Geological and Environmental Sciences, University of Bologna, Via F. Selmi 3, 40126 Bologna, Italy.

ABSTRACT
The variety of reproductive processes and modes among coral species reflects their extraordinary regeneration ability. Scleractinians are an established example of clonal animals that can exhibit a mixed strategy of sexual and asexual reproduction to maintain their populations. This study provides the first description of the annual reproductive cycle and embryogenesis of the temperate species Caryophyllia inornata. Cytometric analyses were used to define the annual development of germ cells and embryogenesis. The species was gonochoric with three times more male polyps than female. Polyps were sexually mature from 6 to 8 mm length. Not only females, but also sexually inactive individuals (without germ cells) and males were found to brood their embryos. Spermaries required 12 months to reach maturity, while oogenesis seemed to occur more rapidly (5-6 months). Female polyps were found only during spring and summer. Furthermore, the rate of gamete development in both females and males increased significantly from March to May and fertilization was estimated to occur from April to July, when mature germ cells disappeared. Gametogenesis showed a strong seasonal influence, while embryos were found throughout the year in males and in sexually inactive individuals without a defined trend. This unusual embryogenesis suggests the possibility of agamic reproduction, which combined with sexual reproduction results in high fertility. This mechanism is uncommon and only four other scleractinians (Pocillopora damicornis, Tubastraea diaphana, T. coccinea and Oulastrea crispata) have been shown to generate their broods asexually. The precise nature of this process is still unknown.

No MeSH data available.


Related in: MedlinePlus

Variation in water temperature, photoperiod, gamete development and fertility.Variation in water temperature and photoperiod (A), gamete development (monthly mean + SE; B), and total fertility (monthly mean + SE; C) from May 2009 to October 2010 at Elba Isle. F = fertilization period.
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pone.0141162.g004: Variation in water temperature, photoperiod, gamete development and fertility.Variation in water temperature and photoperiod (A), gamete development (monthly mean + SE; B), and total fertility (monthly mean + SE; C) from May 2009 to October 2010 at Elba Isle. F = fertilization period.

Mentions: Female polyps were observed between February and July, while males were found during the entire year (Figs 1 and 3). This suggests that the oogenesis process requires less time to reach the final stage of maturation than spermatogenesis, which needed about 12 months (Fig 3). Gonadal size of both females and males increased significantly from March until May, when both photoperiod and water temperature increased after the minimum of the year (Fig 4A and 4B). Fertilization took place from April to July, when photoperiod was the longest of the year (Fig 4A and 4B). Immediately after the fertilization period, we observed the emptying of spermaries and we did not register the presence of oocytes (Fig 3). During the autumn months following the fertilization period, we observed the development of early stages of spermaries maturation in males (Fig 3).


Annual Reproductive Cycle and Unusual Embryogenesis of a Temperate Coral in the Mediterranean Sea.

Marchini C, Airi V, Fontana R, Tortorelli G, Rocchi M, Falini G, Levy O, Dubinsky Z, Goffredo S - PLoS ONE (2015)

Variation in water temperature, photoperiod, gamete development and fertility.Variation in water temperature and photoperiod (A), gamete development (monthly mean + SE; B), and total fertility (monthly mean + SE; C) from May 2009 to October 2010 at Elba Isle. F = fertilization period.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4625958&req=5

pone.0141162.g004: Variation in water temperature, photoperiod, gamete development and fertility.Variation in water temperature and photoperiod (A), gamete development (monthly mean + SE; B), and total fertility (monthly mean + SE; C) from May 2009 to October 2010 at Elba Isle. F = fertilization period.
Mentions: Female polyps were observed between February and July, while males were found during the entire year (Figs 1 and 3). This suggests that the oogenesis process requires less time to reach the final stage of maturation than spermatogenesis, which needed about 12 months (Fig 3). Gonadal size of both females and males increased significantly from March until May, when both photoperiod and water temperature increased after the minimum of the year (Fig 4A and 4B). Fertilization took place from April to July, when photoperiod was the longest of the year (Fig 4A and 4B). Immediately after the fertilization period, we observed the emptying of spermaries and we did not register the presence of oocytes (Fig 3). During the autumn months following the fertilization period, we observed the development of early stages of spermaries maturation in males (Fig 3).

Bottom Line: Not only females, but also sexually inactive individuals (without germ cells) and males were found to brood their embryos.Gametogenesis showed a strong seasonal influence, while embryos were found throughout the year in males and in sexually inactive individuals without a defined trend.This unusual embryogenesis suggests the possibility of agamic reproduction, which combined with sexual reproduction results in high fertility.

View Article: PubMed Central - PubMed

Affiliation: Marine Science Group, Department of Biological, Geological and Environmental Sciences, University of Bologna, Via F. Selmi 3, 40126 Bologna, Italy.

ABSTRACT
The variety of reproductive processes and modes among coral species reflects their extraordinary regeneration ability. Scleractinians are an established example of clonal animals that can exhibit a mixed strategy of sexual and asexual reproduction to maintain their populations. This study provides the first description of the annual reproductive cycle and embryogenesis of the temperate species Caryophyllia inornata. Cytometric analyses were used to define the annual development of germ cells and embryogenesis. The species was gonochoric with three times more male polyps than female. Polyps were sexually mature from 6 to 8 mm length. Not only females, but also sexually inactive individuals (without germ cells) and males were found to brood their embryos. Spermaries required 12 months to reach maturity, while oogenesis seemed to occur more rapidly (5-6 months). Female polyps were found only during spring and summer. Furthermore, the rate of gamete development in both females and males increased significantly from March to May and fertilization was estimated to occur from April to July, when mature germ cells disappeared. Gametogenesis showed a strong seasonal influence, while embryos were found throughout the year in males and in sexually inactive individuals without a defined trend. This unusual embryogenesis suggests the possibility of agamic reproduction, which combined with sexual reproduction results in high fertility. This mechanism is uncommon and only four other scleractinians (Pocillopora damicornis, Tubastraea diaphana, T. coccinea and Oulastrea crispata) have been shown to generate their broods asexually. The precise nature of this process is still unknown.

No MeSH data available.


Related in: MedlinePlus