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| Valonia | |
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| A Valonia species cultivated in an aquarium | |
Scientific classification 
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| Clade: | Viridiplantae |
| Division: | Chlorophyta |
| Class: | UTC clade |
| Order: | Cladophorales |
| Family: | Valoniaceae |
| Genus: | Valonia C.Agardh |
Valonia (C. Agardh, 1823) is a genus of green algae in the Valoniaceae family. The genus Ventricaria is now regarded as a synonym of Valonia.
Taxonomy and nomenclature
The genus Valonia belongs to the order Cladophorales and class Valoniaceae. It comprises several taxonomically acceptable species based from available data and literatures.
Below is a list of common species of Valonia found throughout the tropics:
- Valonia fastigiata Harvey ex J. Agardh 1823
- Valonia ventricosa J.Agardh 1887
- Valonia utricularis (Roth) Agardh 1823
- Valonia aegagropila C. Agardh 1823
- Valonia macrophysa Kützing 1843
- Valonia ovalis C.Agardh 1822
- Valonia chlorocladus Hauck 1886
- Valonia cespitula Zanardini ex Kützing
- Valonia pachynema (G. Martens) Børgesen
- Valonia barbadensis W.R.Taylor, 1969
- Valonia nutrix (Kraft & A.J.K.Millar) Kraft, 2007
- Valonia oblongata J.Agardh, 1887
- Valonia trabeculata Egerod, 1952
General morphological description
Thalli
The succulent thallus of Valonia exhibits various shapes and form depending on species: vesicular or tubular cells forming either irregular cushions or hemispherical domes of intermediate sizes. Thalli color can be green to dark green, olive-green, and brownish-green in some species.
Vesicles and rhizoid systems
The vesicles can be subspherical, subclavate, elongate, or deformed. The branching of vesicles begins at the lenticular cells, which can be terminal and subdichotomous, or lateral and irregular. Seaweeds are attached to the substratum by short rhizoid system to basal rhizoidal cells.
Life history
The life history of the genus Valonia is indistinguishable with the other Siphonocladales family members, particularly genus Boergesenia. Similar in several seaweeds, they exhibit a diplohaplontic life cycle, meaning an alternation between haploid (gametophytic) and diploid (sporophytic) free-living forms completes the cycle.
Specifically in Valonia, production of three-types of quadriflagellate zoospores (diploid) were observed and recorded in the species Valonia fastigiata and Valonia utricularis. These are mitozoospores (diploid) and meiozoospores (haploid) produced from the sporophytic phase, and mitozoospores (haploid) produced by the gametophytes. Eventually, meiozoospores will give rise to the gametophytes, while the mitozoospores produces the sporophytes thus completing the life cycle.
Distribution and ecology
The genus Valonia is widely distributed throughout the tropical region, and some extends to the warm temperate areas. They are mainly found in coastal shallow waters from low intertidal to upper intertidal areas, typically 10 m (33 ft) deep, inhabiting sheltered or wave exposed rocky substrates and pools.
Previous study have shown that the Mediterranean Sea ecotype - Valonia utricularis can extend its biogeographic distribution to warm temperate regions. This is attributed to the seaweed's chloroplast to function as a thermal acclimation organelle in response to exposure of varying temperature levels. It is achieved by controlling the number of pigments thereby decreasing light attainment while increasing the capacity for zeaxanthin-induced energy dissipation. However, ecotypes from the Indian Ocean display photoinhibition when exposed to colder temperatures.
In addition, Valonia ulticularis, along with other intertidal seaweeds (Gelidium corneum, Osmundea pinnatifida, and Caulacanthus ustulatus) where found to influence the vertical distribution of peracarid crustaceans at the lower intertidal zones. Highest peak of peracarids were found to coincide with the highest seasonal growth of the associated macroalgae (around April–August). However, there are also some important ecological factors such as weather conditions, competitions, and predation which may also influence distribution patterns.
Economic products and uses
The genus Valonia, specifically Valonia aegagropila is utilized for human consumption as food. It contains numerous natural products/ secondary metabolites, such as, Pigments (carotene, chlorophyll a, chlorophyll b, lutein, siphonaxanthin, zeaxanthin, siphonein), Polysaccharide (starch), as well as Minerals (heavy metals).
Valonia ventricosa which compose similar natural products is often studied for the crystalline-structure of its cellulose to promote applications on accurate physical measurements.
The crystal-structure of Valonia cellulose Iβ was studied by Finkenstadt and Millane (1998). Using X-ray fiber diffraction analysis, it resolves the ambiguities in the cellulose structure that has been baffling for years. The crystalline structures were shown to be in parallel- up arrangements. The packing of the cellulose sheets of Valonia is similar to the ramie cellulose (ramie fiber) found in other macroalgae and higher plant taxa. Application in fabric production can be explored due to the fact that ramie fiber is specifically used in that industry.
Production of levulinic acid from Valonia aegagropila and another Cladophorales, Chaetomorpha linum, were also explored and developed in recent years. Using an acid-catalyzed conversion, Valonia aegagropila were studied as a potential source for levulinic acid. The results were promising, achieving 16 wt% from V. aegagropila, calculated with respect to the initial dried biomass. This supports the potential use of the macroalgae as starting feedstocks for renewable biofuels that addresses natural resource and environmental issues.
Amino acids such as alanine, glutamine, methionine, proline, asparagine among others, as well as minerals such as calcium (Ca), magnesium (Mg), sodium (Na), potassium (K), and chlorine (Cl), were also found in Valonia, specifically Valonia fastigiata.
Furthermore, unsaturated fatty acids where shown to be high of concentration in Valonia aegagropila, together with other macroalgae (Agarophyton tenuistipitatum, and brown seaweeds (Pheaophyta). Unsaturated fatty acids are healthy fats that can be utilized for medicinal applications, e.g. improving cholesterol levels, reduce inflammations, and stabilize heart rhythms among others.
References
- ^ "Algaebase". Retrieved 10 September 2014.
- Guiry, M.D., and Guiry G.M. (2008). "Algaebase". Algaebase.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - Trono Jr., Gavino C. (1997). Field Guide and Atlas of the Seaweed Resources of the Philippines. Makati City, Philippines: Bookmark, Inc. pp. 26–28. ISBN 971-569-252-4.
- Guiry, M.D., and Guiry, G.M. (2022). "Algaebase". Algaebase. Retrieved January 19, 2022.
{{cite web}}: CS1 maint: multiple names: authors list (link) - Beutlich, A., Borstelmann, B., Redemmann, R., Speckenback, K., and Schnetter, R. (1990). "Notes on the life histories of Boergesenia and Valonia (Siphonocladales, Chlorophyta)". Hydrobiologia. 204: 425–434. doi:10.1007/BF00040267. S2CID 22224930.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - Titlyanov, A.E., Titlyanova, V.T., Li, X., and Huang H. (2016). Coral reef marine plants of Hainan island. Academic Press.
{{cite book}}: CS1 maint: multiple names: authors list (link) - Coppejans, E., Prathep, A., Leliaert, F., Lewmanomont, K., and De Clerk, O. (2010). Seaweeds of Mu Ko Tha Lae Tai (SE Thailand) Methodologies and field guide to the dominant species. Bangkok 10400, Thailand: Biodiversity Research and Training Program (BRT).
{{cite book}}: CS1 maint: location (link) CS1 maint: multiple names: authors list (link) - Eggert, A., Van Hasselt, P.R., and Breeman A.M. (2003). "Differences in thermal acclimation of chloroplast functioning in two ecotypes of Valonia utricularis (Chlorophyta)". European Journal of Phycology. 38 (2): 123–131. Bibcode:2003EJPhy..38..123E. doi:10.1080/0967026031000085823. S2CID 85629181.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - Guerra-García, J.M., Baeza-Rojano, E., Cabezas, M.P., and García-Gómez, J.C. (2010). "Vertical distribution and seasonality of peracarid crustaceans associated with intertidal macroalgae". Journal of Sea Research. 65 (2): 256–264. doi:10.1016/j.seares.2010.12.001.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - ^ Trono Jr., Gavino C. (1997). Field Guide & Atlas of the Seaweed Resources of the Philippines. Makati City, Philippines: Bookmark. p. 27. ISBN 971-569-252-4.
- Trono Jr., Gavino C. (1997). Field Guide and Atlas of the Seaweed Resources of the Philippines. Makati City, Philippines: Bookmark. pp. 26–28. ISBN 971-569-252-4.
- Finkenstadt, V.L., and Millane, R.P. (1998). "Crystal Structure of Valonia Cellulose Iβ". Macromolecules. 31 (22): 7776–7783. Bibcode:1998MaMol..31.7776F. doi:10.1021/ma9804895 – via ACS Publications.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - Galleti, A.M.R., Antonetti, C., Licursi, D., Mussi, L., Balestri, E., and Lardicci, C. (2019). "Levulinic Acid Production from the Green Macroalgae Chaetomorpha linum and Valonia aegagropila Harvested in the Orbetello Lagoon". Chemical Engineering Transactions. 74: 103–108 – via The Italian Association of Chemical Engineering.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - Zhao, Z., Zhang, S., and Zhao, L. (2021). "Fatty Acid Composition of Macroalgae from Nao Zhou Island". Revista Brasileira de Farmacognosia. 31 (4): 477–480. doi:10.1007/s43450-021-00153-6. S2CID 244228454 – via Springer Link.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - "The Nutrition Source - Types of Fat". Harvard T.H. Chan - School of Public Health. 9 June 2014. Retrieved January 22, 2022.
- See the NCBI webpage on Valonia. Data extracted from the "NCBI taxonomy resources". National Center for Biotechnology Information. Retrieved 2007-03-19.
| Taxon identifiers | |
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| Valonia | |