| Monostroma | |
|---|---|
_(14780855412).jpg) | |
| Monostroma hariotii | |
Scientific classification | |
| Kingdom: | Plantae |
| Division: | Chlorophyta |
| Class: | Ulvophyceae |
| Order: | Ulotrichales |
| Family: | Monostromataceae |
| Genus: | Monostroma Thuret |
| Selected species | |
Monostroma is agenus of marinegreen algae (seaweed) in the familyMonostromataceae.[1] As the name suggests, algae of this genus aremonostromatic (single cell layered).Monostroma kuroshiense, an algae of this genus, is commercially cultivated inEast Asia andSouth America for the edible product "hitoegusa-nori" or "hirohano-hitoegusa nori", popularsushi wraps.Monostromaoligosaccharides withdegree of polymerization 6 prepared byagarase digestion fromMonostroma nitidumpolysaccharides have been shown to be an effective prophylactic agent duringin vitro andin vivo tests againstJapanese encephalitis viral infection. The sulfated oligosaccharides fromMonostroma seem to be promising candidates for further development as antiviral agents.[2] The genusMonostroma is the most widely cultivated genus among greenseaweeds.
Species-level classification within this genus is quite problematic and no consensus exists among algal taxonomists. This genus is oftentimes referred as "Gayralia", howeverGayralia andMonostroma are congeneric. A number of monostromatic algal species have been removed from this genus, including Kornmannia, Ulvopsis and Capsosiphon. Currently accepted working-classification of monostromatic green algae[3] is provided as a figure. A taxonomic field-identification dichotomous key for this genus is available[4]
Largest phylogeographic assessment of this genus yet conducted in SWJapan revealed existence ofsympatric speciation in apanmictic population; the first report of sympatric speciation in algae[5]
A number of peer-reviewed scientific literature exists on theecophysiology of this algal genus.[6] Natural and cultivated sexually reproducing environmental samples, as well as sexually reproducing and serendipitously discovered asexually reproducingecotypes of monostromatic green alga fromTosa Bay, Japan are conspecific (belong to the same species).[7] Patterns of seasonal fluctuations in its thallus lengths werehabitat specific and recur annually.[8] Both appearance and decay of thalli were earlier at high saline habitats, suggesting that salinity positively influences either maturation ofsporophytes or senescence ofgametophytes. Results from life cycle, thallus ontogeny, gametangial ontogeny and phylogenetic analyses suggest that this algal genus is evolutionarily affiliated in the order Ulotrichales.[9] Type of life cycle is not a valid diagnostic character for the species circumscription in Monostromataceae[10]
Gametogenesis in this alga occurs in discontinuous patches along the frontal apex and thegametes release synchronously in a posterior faced linear fashion by the dehiscence of gametangial sheath, leading to the thallic disintegration.[11] The overall primarysex ratio of this alga is about 1:1 which is likely to reflect Fisherian selection.[12]
In Korea, edibleMonostroma species such asMonostroma nitidum are calledparae (파래), and eaten as anamul vegetable.
In Japan, driedMonostroma kuroshiense calledaonori is used to season dishes such astakoyaki andokonomiyaki. InOkinawa, it is used in a soup called āsa nu ushiru.