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Intrinsic constraints on sympodial growth morphologies of azooxanthellate scleractinian coral Dendrophyllia.

Sentoku A, Ezaki Y - PLoS ONE (2013)

Bottom Line: However, little is known about the intrinsic mechanisms that control asexual reproduction and the resultant morphologies of colonies.The strict constraints on budding regularities and shifts in budding sites observed in the sympodial growth forms of corals greatly affect resulting morphologies in azooxanthellate coral colonies.A precise understanding of these intrinsic constraints leads to a fundamental comprehension of colony-forming mechanisms in modular organisms.

View Article: PubMed Central - PubMed

Affiliation: Department of Geosciences, Graduate School of Science, Osaka City University, Osaka, Japan. sentoku@sci.osaka-cu.ac.jp

ABSTRACT

Background: Asexual increase occurs in virtually all colonial organisms. However, little is known about the intrinsic mechanisms that control asexual reproduction and the resultant morphologies of colonies. Scleractinian corals, both symbiotic (zoaxanthellate) and non-symbiotic (azooxanthellate) corals are known to form elaborate colonies. To better understand the growth mechanisms that control species-specific type of colony in azooxanthellate dendrophyllid scleractinian corals, we have studied details of the budding pattern in the sympodial colonies of Dendrophyllia boschmai and Dendrophyllia cribrosa.

Principal findings: Budding exhibits the following regularities: (1) the two directive septa of offset corallites are oriented almost perpendicular to the growth direction of parent corallites; (2) offsets generally occur in either of the lateral primary septa that occur on one side of a corallite; the individuals thus show a definite polarity with respect to the directive septa, and only when branching dichotomously offsets occur in both primary septa; (3) the lateral corallites grow more-or-less diagonally upwards; and (4) the regularities and polarities are maintained throughout growth. Given these regularities, D. boschmai grows in a zigzag fashion by alternately budding on the right and left sites. In contrast, D. cribrosa grows helically by budding at a particular site.

Conclusions/significance: The strict constraints on budding regularities and shifts in budding sites observed in the sympodial growth forms of corals greatly affect resulting morphologies in azooxanthellate coral colonies. A precise understanding of these intrinsic constraints leads to a fundamental comprehension of colony-forming mechanisms in modular organisms.

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Measured parts of the lateral corallites of a colony.A, Orientation of the directive septa, defined as the angle (φ) between a line connecting the two directive septa (solid line) and a horizontal line (dotted). B, Budding sites. The two directive septa are indicated by arrows, and the four lateral primary septa are indicated by white triangles. C, Inclination of budding, defined as the angle between the direction of the lateral corallites (solid line) and a horizontal line (dotted line) oriented perpendicular to the growth direction of the parent corallite (white dotted line).
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pone-0063790-g003: Measured parts of the lateral corallites of a colony.A, Orientation of the directive septa, defined as the angle (φ) between a line connecting the two directive septa (solid line) and a horizontal line (dotted). B, Budding sites. The two directive septa are indicated by arrows, and the four lateral primary septa are indicated by white triangles. C, Inclination of budding, defined as the angle between the direction of the lateral corallites (solid line) and a horizontal line (dotted line) oriented perpendicular to the growth direction of the parent corallite (white dotted line).

Mentions: Orientations of directive septa: the angle between the directive septa of a lateral corallite and the growth direction of the parent corallite (Fig. 3A).


Intrinsic constraints on sympodial growth morphologies of azooxanthellate scleractinian coral Dendrophyllia.

Sentoku A, Ezaki Y - PLoS ONE (2013)

Measured parts of the lateral corallites of a colony.A, Orientation of the directive septa, defined as the angle (φ) between a line connecting the two directive septa (solid line) and a horizontal line (dotted). B, Budding sites. The two directive septa are indicated by arrows, and the four lateral primary septa are indicated by white triangles. C, Inclination of budding, defined as the angle between the direction of the lateral corallites (solid line) and a horizontal line (dotted line) oriented perpendicular to the growth direction of the parent corallite (white dotted line).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3646883&req=5

pone-0063790-g003: Measured parts of the lateral corallites of a colony.A, Orientation of the directive septa, defined as the angle (φ) between a line connecting the two directive septa (solid line) and a horizontal line (dotted). B, Budding sites. The two directive septa are indicated by arrows, and the four lateral primary septa are indicated by white triangles. C, Inclination of budding, defined as the angle between the direction of the lateral corallites (solid line) and a horizontal line (dotted line) oriented perpendicular to the growth direction of the parent corallite (white dotted line).
Mentions: Orientations of directive septa: the angle between the directive septa of a lateral corallite and the growth direction of the parent corallite (Fig. 3A).

Bottom Line: However, little is known about the intrinsic mechanisms that control asexual reproduction and the resultant morphologies of colonies.The strict constraints on budding regularities and shifts in budding sites observed in the sympodial growth forms of corals greatly affect resulting morphologies in azooxanthellate coral colonies.A precise understanding of these intrinsic constraints leads to a fundamental comprehension of colony-forming mechanisms in modular organisms.

View Article: PubMed Central - PubMed

Affiliation: Department of Geosciences, Graduate School of Science, Osaka City University, Osaka, Japan. sentoku@sci.osaka-cu.ac.jp

ABSTRACT

Background: Asexual increase occurs in virtually all colonial organisms. However, little is known about the intrinsic mechanisms that control asexual reproduction and the resultant morphologies of colonies. Scleractinian corals, both symbiotic (zoaxanthellate) and non-symbiotic (azooxanthellate) corals are known to form elaborate colonies. To better understand the growth mechanisms that control species-specific type of colony in azooxanthellate dendrophyllid scleractinian corals, we have studied details of the budding pattern in the sympodial colonies of Dendrophyllia boschmai and Dendrophyllia cribrosa.

Principal findings: Budding exhibits the following regularities: (1) the two directive septa of offset corallites are oriented almost perpendicular to the growth direction of parent corallites; (2) offsets generally occur in either of the lateral primary septa that occur on one side of a corallite; the individuals thus show a definite polarity with respect to the directive septa, and only when branching dichotomously offsets occur in both primary septa; (3) the lateral corallites grow more-or-less diagonally upwards; and (4) the regularities and polarities are maintained throughout growth. Given these regularities, D. boschmai grows in a zigzag fashion by alternately budding on the right and left sites. In contrast, D. cribrosa grows helically by budding at a particular site.

Conclusions/significance: The strict constraints on budding regularities and shifts in budding sites observed in the sympodial growth forms of corals greatly affect resulting morphologies in azooxanthellate coral colonies. A precise understanding of these intrinsic constraints leads to a fundamental comprehension of colony-forming mechanisms in modular organisms.

Show MeSH