Glyceria fluitans | |
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Scientific classification | |
Kingdom: | Plantae |
Clade: | Tracheophytes |
Clade: | Angiosperms |
Clade: | Monocots |
Clade: | Commelinids |
Order: | Poales |
Family: | Poaceae |
Subfamily: | Pooideae |
Genus: | Glyceria |
Species: | G. fluitans |
Binomial name | |
Glyceria fluitans | |
Glyceria fluitans (syns Festuca fluitans, Poa fluitans, Panicularia fluitans), known as floating sweet-grass [2] and water mannagrass, is a species of perennial grass in the genus Glyceria native to Europe, the Mediterranean region and Western Asia and occurring in wet areas such as ditches, riverbanks and ponds.
It has a creeping rootstock, a thick stem which rises to one metre. The leaves are long, narrow and pale green, rough on both sides, often folded at the keel which lies on the surface of the water.
Before the 19th century, the grains were widely harvested in Central Europe and Sweden, and traded as far as England. [4] It was cooked and eaten as gruel. [4]
When a shoot is submerged in floodwater there is a strong reduction of diffusion of gases which limits oxygen and carbon dioxide availability. [5] To handle the poor gas exchange while submerged, Glyceria fluitans forms a gas film around the leaves. [6] The gas film allows to increase the gas exchange since the diffusion of gas within the film is rapid. [7] Glyceria fluitans has two kind of leaves: floating leaves and aerial leaves. Floating leaves form a gas film only on the adaxial side, instead aerial leaves form it on both sides. [6] The formation of a gas film is caused from the superhydrophobicity of the leaves, which is provoked by the special structure of the leaves. Indeed, they have a plicate shape with ridges and grooves, on the microscale they have convex papillose epidermal cells forming papillae and three-dimensional epicuticular waxes. [6] A gas film vanishes typically after 2–6 days of submergence because the leaves become hydrophilic. [8] Regarding the beneficial trait of the gas film development, it can be said that Glyceria fluitans through it enhances the gas exchange and therefore the photosynthesis under flood conditions, but it is seen as a short term strategie. [6]
Glyceria fluitans is a component of purple moor grass and rush pastures, a type of Biodiversity Action Plan habitat in the UK. This habitat occurs on poorly drained neutral and acidic soils of the lowlands and upland fringe. It is found in the South West of England, especially in Devon.
At the Great Fen, researchers are running trials with Glyceria fluitans in order to assess its physical and financial viability as a crop in wet farming systems. [9] Glyceria fluitans was chosen because it has been consumed by humans for a long time and because of its tolerance to a wide range of growing conditions. [10] This tolerance originates from the fact that Glyceria fluitans is to some extent self-sterile and therefore outbreeding, which allows for adaptation. [11]
The use and cultivation of Glyceria fluitans disappeared little by little during the 19th and 20th century due to its long gathering time and the disappearance of wetlands. [12] For these reasons, known farming techniques are old and not very applicable to today's production systems anymore.
Glyceria fluitans is harvested in the second half of June or early July. [12] The maturation and harvest time of Glyceria fluitans were interesting for farmers in the past centuries because it preceded the wheat and rye harvest by 1 month, a period of significant cereal shortage. [12] The grains of Glyceria fluitans were harvested with a sieve at the morning dew. The sieves were described with long handles and only strong people could use them. After the harvest, grains were dried out and grinded in a mortar filled with straw at the bottom so that the shells could be removed. [12] The reasons why Glyceria fluitans grains were harvested at the morning dew are the following: firstly, grains tend to stick better to the sieves when humid. Secondly, the grains of dry plants tend to fall more easily on the ground at the smallest movement causing yield loses. [12]
However, these harvest techniques are not suitable for today's agricultural production and new cultivars through genetic breeding should be developed. [13]
The sowing of Glyceria fluitans takes place in summer. The seeding density is 8 to 12 lbs per acre. [12]
Glyceria fluitans grains were popular in Poland, Germany, Hungary and other European countries for their sweet taste and nutrient richness. In Poland, foods containing Glyceria fluitans were pointed out as specialities of the local cuisine. Originally, Glyceria fluitans was used to prepare dishes as sweet cakes, flatbreads, dumplings, with butter or boiled milk, broths and soups, with oriental spices, as well as in sausages as binding additive. [12]
Due to its healthy properties, between the 17th and 18th century, its consume was advised by pharmacopoeias to people with debilitating diseases as well as malnourished young people. [14] [15] [16] [17]
100 g of Glyceria fluitans grains (endosperm, ca. 13.5% water content) contain about: 9.69% of protein, 0.43% of total fat, 75.06% of carbohydrate (starch and sugar), 0.21% of dietary fiber and 0.61% of ash. [18]
Plant cells are the cells present in green plants, photosynthetic eukaryotes of the kingdom Plantae. Their distinctive features include primary cell walls containing cellulose, hemicelluloses and pectin, the presence of plastids with the capability to perform photosynthesis and store starch, a large vacuole that regulates turgor pressure, the absence of flagella or centrioles, except in the gametes, and a unique method of cell division involving the formation of a cell plate or phragmoplast that separates the new daughter cells.
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Wheat is a grass widely cultivated for its seed, a cereal grain that is a staple food around the world. The many species of wheat together make up the genus Triticum ; the most widely grown is common wheat. The archaeological record suggests that wheat was first cultivated in the regions of the Fertile Crescent around 9600 BC. Botanically, the wheat kernel is a caryopsis, a type of fruit.
A fen is a type of peat-accumulating wetland fed by mineral-rich ground or surface water. It is one of the main types of wetland along with marshes, swamps, and bogs. Bogs and fens, both peat-forming ecosystems, are also known as mires. The unique water chemistry of fens is a result of the ground or surface water input. Typically, this input results in higher mineral concentrations and a more basic pH than found in bogs. As peat accumulates in a fen, groundwater input can be reduced or cut off, making the fen ombrotrophic rather than minerotrophic. In this way, fens can become more acidic and transition to bogs over time.
A bog or bogland is a wetland that accumulates peat as a deposit of dead plant materials – often mosses, typically sphagnum moss. It is one of the four main types of wetlands. Other names for bogs include mire, mosses, quagmire, and muskeg; alkaline mires are called fens. A bayhead is another type of bog found in the forest of the Gulf Coast states in the United States. They are often covered in heath or heather shrubs rooted in the sphagnum moss and peat. The gradual accumulation of decayed plant material in a bog functions as a carbon sink.
Aquatic plants are vascular plants that have adapted to live in aquatic environments. They are also referred to as hydrophytes or macrophytes to distinguish them from algae and other microphytes (phytoplanktons). In lakes, rivers and wetlands, aquatic vegetations provide cover for aquatic animals such as fish, amphibians and aquatic insects, create substrate for benthic invertebrates, produce oxygen via photosynthesis, and serve as food for some herbivorous wildlife. Familiar examples of aquatic plants include waterlily, lotus, duckweeds, mosquito fern, floating heart, water milfoils, mare's tail, water lettuce and water hyacinth.
Jean Senebier was a Genevan Calvinist pastor and naturalist. He was chief librarian of the Republic of Geneva. A pioneer in the field of photosynthesis research, he provided extensive evidence that plants consume carbon dioxide and produced oxygen. He also showed a link between the amount of carbon dioxide available and the amount of oxygen produced and determined that photosynthesis took place at the parenchyma, the green fleshy part of the leaf.
C4 carbon fixation or the Hatch–Slack pathway is one of three known photosynthetic processes of carbon fixation in plants. It owes the names to the 1960s discovery by Marshall Davidson Hatch and Charles Roger Slack.
Rumex palustris, or marsh dock, is a plant species of the genus Rumex, found in Europe. The species is a dicot belonging to the family Polygonaceae. The species epithet palustris is Latin for "of the marsh" which indicates its common habitat.
Nymphoides peltata is perennial, rooted aquatic plant with floating leaves of the family Menyanthaceae.
Stuckenia pectinata, commonly called sago pondweed or fennel pondweed, and sometimes called ribbon weed, is a cosmopolitan water plant species that grows in fresh and brackish water on all continents except Antarctica.
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Ranunculus fluitans is a species of buttercup. It is a perennial water plant, which when in favourable conditions can grow up to 6 m (20 ft) height.
Elachista pomerana is a moth of the family Elachistidae found in Europe.
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Ethylene (CH
2=CH
2) is an unsaturated hydrocarbon gas (alkene) acting as a naturally occurring plant hormone. It is the simplest alkene gas and is the first gas known to act as hormone. It acts at trace levels throughout the life of the plant by stimulating or regulating the ripening of fruit, the opening of flowers, the abscission (or shedding) of leaves and, in aquatic and semi-aquatic species, promoting the 'escape' from submergence by means of rapid elongation of stems or leaves. This escape response is particularly important in rice farming. Commercial fruit-ripening rooms use "catalytic generators" to make ethylene gas from a liquid supply of ethanol. Typically, a gassing level of 500 to 2,000 ppm is used, for 24 to 48 hours. Care must be taken to control carbon dioxide levels in ripening rooms when gassing, as high temperature ripening (20 °C; 68 °F) has been seen to produce CO2 levels of 10% in 24 hours.