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Valonia (C. Agardh, 1823) is a genus of green algae in the Valoniaceae family.[1] The genus Ventricaria is now regarded as a synonym of Valonia.[1]
The genus Valonia belongs to the order Cladophorales and class Valoiaceae. It comprises several taxonomically acceptable species based from available data and literatures.[2]
Below is a list of common species of Valonia found throughout the tropics:
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.
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.[3][4]
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.[5]
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.[6][7]
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.[8]
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.[9]
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).[10]
Valonia ventricosa which compose similar natural products is often studied for the crystalline-structure of its cellulose to promote applications on accurate physical measurements.[11]
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.[12]
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.[13]
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.[10]
Furthermore, unsaturated fatty acids where shown to be high of concentration in Valonia aegagropila, together with other macroalgae (Agarophyton tenuistipitatum, and brown seaweeds (Pheaophyta).[14] 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.[15]
{{cite journal}}: CS1 maint: multiple names: authors list (link) {{cite web}}: CS1 maint: multiple names: authors list (link) {{cite journal}}: CS1 maint: multiple names: authors list (link) {{cite book}}: CS1 maint: multiple names: authors list (link) {{cite book}}: CS1 maint: location (link) CS1 maint: multiple names: authors list (link) {{cite journal}}: CS1 maint: multiple names: authors list (link) {{cite journal}}: CS1 maint: multiple names: authors list (link) {{cite journal}}: CS1 maint: multiple names: authors list (link) {{cite journal}}: CS1 maint: multiple names: authors list (link) {{cite journal}}: CS1 maint: multiple names: authors list (link) {{cite web}}: CS1 maint: url-status (link) 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.
Valonia es un género de algas verdes de la familia Valoniaceae.[1]
El talo está compuesto por células comprimidas o débilmente entrelazadas, y puede alcanzar 25 cm de diámetro. Las células, que pueden tener un diámetro de 1 cm, son multinucleadas, poseen numerosos cloroplastos y tienen forma de elipsoide. Algunas especies tienen una forma simétrica. Las células basales se fijan al sustrato. Posee ramificaciones de densidad variable según la especie y el ambiente.[1]
Es utilizada en estudios sobre intercambios iónicos y potencial de membrana.[1]
Valonia macrophysa
Valonia ventricosa
Valonia fastigiata
Valonia es un género de algas verdes de la familia Valoniaceae.
Valonia est un genre d'algues vertes de la famille des Valoniaceae. La taille d'une seule cellule pluri-nucléée peut atteindre 2 cm chez certaines espèces.
L'espèce-type (l'holotype) est Valonia aegagropila.
L'étymologie du nom de genre Valonia n'est pas claire. Le nom aurait été attribué par le naturaliste italien du XVIIIe siècle Giuseppe Ginanni[note 1] pour nommer une algue commune dans la lagune de Venise[1]. Par la suite, au XIXe siècle, le botaniste Agardh utilisa ce nom vernaculaire en tant que genre[1].
Selon AlgaeBase (30 avril 2013)[2] et World Register of Marine Species (30 avril 2013)[3] :
Selon ITIS (30 avril 2013)[4] :
Valonia est un genre d'algues vertes de la famille des Valoniaceae. La taille d'une seule cellule pluri-nucléée peut atteindre 2 cm chez certaines espèces.
L'espèce-type (l'holotype) est Valonia aegagropila.
Valonia C.Agardh, 1823
Типовой вид
Валония (лат. Valonia) — род морских зелёных водорослей из порядка кладофоровых (Cladophorales).
Встречаются по всему миру в тропических и субтропических морях. Таллом 5—15 см, кустистый, из небольшого числа крупных многоядерных клеток или из одной гигантской клетки, с небольшими ризоидами при основании. Размножение зооспорами, изредка — изогамия. Используются как объект для изучения внутриклеточных процессов.
Около 10 видов:
Валония (лат. Valonia) — род морских зелёных водорослей из порядка кладофоровых (Cladophorales).
バロニア（Valonia）は緑色植物門に含まれる海藻の属である。藻体は肉眼的な大きさの球形の細胞（右写真）より成る。後述するように深所型緑藻と呼ばれ、温帯から熱帯の海洋域、潮間帯から比較的深い場所まで分布する。「バロニア」の名はイタリアの植物学者 Valoni に献名されたものである[1]。
バロニアは巨大な単細胞生物である。細胞は風船のように膨らんだ形状で球形から亜球形、基部で基物に付着している[2]。色は濃緑色、表面に光沢があり、美しさを称えられる[3]。細胞の内部は液状の原形質で満たされており、細胞質や液胞のほか多数の葉緑体、核を含む（多核体）[4]。細胞の表面はセルロース性の細胞壁で覆われている。このセルロースの合成複合体は陸上植物のようなロゼット型ではなく、狭義の緑藻類と同じ三列の直線的な配置をとっており、太く丈夫な繊維を形成することができる[5]。
バロニアの細胞からは容易にプロトプラストを作成することができる[3]。滅菌海水を用意し、藻体に傷を付けて原形質を流しこめば良い。原形質は海水中で球形となり、数分で表面に細胞膜が形成されてプロトプラストとなる。プロトプラストは数週間の培養の後に、元と同じ藻体に戻る。このようなプロトプラストによる分散・増殖と個体の再生は天然でも見られ、イワヅタ目やミドリゲ目の藻類で多く知られている。
光合成色素としてはクロロフィル a および b を持つ。他に光合成補助色素として、深所型緑藻に特徴的なカロテノイドであるシフォネインやシフォナキサンチンを持つ[6]。これらのカロテノイドは緑色光を効率的に吸収し、深所での光合成を可能にしている。
バロニアの細胞分裂は細胞の表面付近で起こる[2]。細胞が成熟すると、細胞質が細胞壁の直下に凝集し、細胞分裂を経て遊走細胞（遊走子もしくは配偶子）が形成される。遊走細胞は細胞壁の孔から放出される。胞子体と配偶体は同型である[4][7]。
バロニア属は40種以上が記載され、そのうち10種が分類学的に受け入れられている種である[4]。日本近海では3種が知られている[8]。以下ではその3種について、日本近海以外の分布に関する情報が抜けているかもしれない。
![[icon]](http://ja.wikipedia.org/wiki/%E3%83%95%E3%82%A1%E3%82%A4%E3%83%AB:Wiki_letter_w_cropped.svg){kind=small}
アオサ藻綱は多くの食用海藻を含むが、バロニアの食用利用は知られていない[12]。観賞用に販売されることがある一方、アクアリウムに予期せず繁茂して駆除の対象となる場合もある。
バロニア（Valonia）は緑色植物門に含まれる海藻の属である。藻体は肉眼的な大きさの球形の細胞（右写真）より成る。後述するように深所型緑藻と呼ばれ、温帯から熱帯の海洋域、潮間帯から比較的深い場所まで分布する。「バロニア」の名はイタリアの植物学者 Valoni に献名されたものである。
