Azolla filiculoides

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Azolla filiculoides
Water Fern Azolla filiculoides (6165580451).jpg
Status TNC G5.svg
Secure  (NatureServe)
Scientific classification OOjs UI icon edit-ltr.svg
Kingdom: Plantae
Clade: Tracheophytes
Division: Polypodiophyta
Class: Polypodiopsida
Order: Salviniales
Family: Salviniaceae
Genus: Azolla
Species:
A. filiculoides
Binomial name
Azolla filiculoides
Synonyms [2] [3]
  • Azolla arbusculaDesv.
  • Azolla caroliniana Willd.
  • Azolla japonicaFranch. & Sav.
  • Azolla magellanicaWilld.
  • Azolla microphyllaKaulf.
  • Azolla pinnata var. japonica(Franch. & Sav.) Franch. & Sav.
  • Azolla squamosaMolina

Azolla filiculoides (water fern) is a species of aquatic fern. It is native to warm temperate and tropical regions of the Americas, and has been introduced to Europe, North and sub-Saharan Africa, China, Japan, New Zealand, Australia, the Caribbean and Hawaii. [4]

Contents

It is a floating aquatic fern, with very fast growth, capable of spreading over lake surfaces to give complete coverage of the water in only a few months. Each individual plant is 1–2 cm across, green tinged pink, orange or red at the edges, branching freely, and breaking into smaller sections as it grows. It is not tolerant of cold temperatures; in temperate regions it largely dies back in winter, surviving by means of submerged buds. It harbors the diazotrophic organism Nostoc azollae in specialized leaf pockets. This ancient symbiosis allows N. azollae to fix nitrogen from the air and contribute to the fern's metabolism. [5] [6]

Fossil records from as recent as the last interglacials are known from several locations in Europe (Hyde et al. 1978). 50 million years ago, a species similar to Azolla filiculoides may have played a pivotal role in cooling the planet in what is known as the Azolla event. [7]

Azolla filiculoides was one of the first two fern species with a reference genome published. [8] [7]

Identification

The only sure method of distinguishing this species from Azolla cristata (long incorrectly known as A. caroliniana) is to examine the trichomes on the upper surfaces of the leaves. Trichomes are small protuberances that create water resistance. They are unicellular in A. filiculoides but septate (two-celled) in A. cristata. [9]

Cultivation

The species has been introduced to many regions of the Old World, grown for its nitrogen-fixing ability that may be used to enhance the growth rate of crops grown in water, such as rice, or by removal from lakes for use as green manure. [10] A. filiculoides is frequently cultivated in aquariums and ponds, where it can become easily dominant over other species.

Invasive species

A. filiculoides was first recorded in Europe in 1870s–1880s, when the species may have been accidentally transported in ballast water, with fry, or directly as an ornamental or aquarium plant. It was introduced into Asia from East Germany in 1977 as an alternative to the cold susceptible native strain of A. pinnata, used as a green manure in the rice industry. A. filiculoides has also been spread around the world as a research model plant for the study of AzollaAnabaena symbiosis. In the areas of introduction, A. filiculoides is capable of rapid growth, especially in eutrophic ecosystems, and outcompete native aquatic plants. The dense mat of A. filiculoides causes lack of light penetration and an anaerobic environment due to detritus decomposition, causing a drastic reduction of water quality, aquatic biodiversity and ecosystem funcion. [11] [12]

See also

Related Research Articles

<span class="mw-page-title-main">Fern</span> Class of vascular plants

The ferns are a group of vascular plants that reproduce via spores and have neither seeds nor flowers. They differ from mosses by being vascular, i.e., having specialized tissues that conduct water and nutrients and in having life cycles in which the branched sporophyte is the dominant phase.

<span class="mw-page-title-main">Aquatic plant</span> Plant that has adapted to living in an aquatic environment

Aquatic plants are plants that have adapted to living in aquatic environments. They are also referred to as hydrophytes or macrophytes to distinguish them from algae and other microphytes. A macrophyte is a plant that grows in or near water and is either emergent, submergent, or floating. In lakes and rivers macrophytes provide cover for fish, substrate for aquatic invertebrates, produce oxygen, and act as food for some fish and wildlife.

<span class="mw-page-title-main">Rhizobia</span> Nitrogen fixing soil bacteria

Rhizobia are diazotrophic bacteria that fix nitrogen after becoming established inside the root nodules of legumes (Fabaceae). To express genes for nitrogen fixation, rhizobia require a plant host; they cannot independently fix nitrogen. In general, they are gram negative, motile, non-sporulating rods.

<span class="mw-page-title-main">Green manure</span> Organic material left on an agricultural field to be used as a mulch or soil amendment

In agriculture, a green manure is a crop specifically cultivated to be incorporated into the soil while still green. Typically, the green manure's biomass is incorporated with a plow or disk, as is often done with (brown) manure. The primary goal is to add organic matter to the soil for its benefits. Green manuring is often used with legume crops to add nitrogen to the soil for following crops, especially in organic farming, but is also used in conventional farming.

<i>Azolla</i> Genus of aquatic plants

Azolla is a genus of seven species of aquatic ferns in the family Salviniaceae. They are extremely reduced in form and specialized, looking nothing like other typical ferns but more resembling duckweed or some mosses. Azolla filiculoides is one of just two fern species for which a reference genome has been published. It is believed that this genus grew so prolifically during the Eocene that it triggered a global cooling event that has lasted to the present.

<i>Salvinia</i> Genus of aquatic plants

Salvinia, a genus in the family Salviniaceae, is a floating fern named in honor of Anton Maria Salvini, a 17th-century Italian scientist. Watermoss is a common name for Salvinia. The genus was published in 1754 by Jean-François Séguier, in his description of the plants found round Verona, Plantae Veronenses Twelve species are recognized, at least three of which are believed to be hybrids, in part because their sporangia are found to be empty.

<span class="mw-page-title-main">Heterocyst</span>

Heterocysts or heterocytes are specialized nitrogen-fixing cells formed during nitrogen starvation by some filamentous cyanobacteria, such as Nostoc, Cylindrospermum, and Anabaena. They fix nitrogen from dinitrogen (N2) in the air using the enzyme nitrogenase, in order to provide the cells in the filament with nitrogen for biosynthesis.

Diazotrophs are bacteria and archaea that fix gaseous nitrogen in the atmosphere into a more usable form such as ammonia.

<i>Anabaena</i> Genus of bacteria

Anabaena is a genus of filamentous cyanobacteria that exist as plankton. They are known for nitrogen-fixing abilities, and they form symbiotic relationships with certain plants, such as the mosquito fern. They are one of four genera of cyanobacteria that produce neurotoxins, which are harmful to local wildlife, as well as farm animals and pets. Production of these neurotoxins is assumed to be an input into its symbiotic relationships, protecting the plant from grazing pressure.

<i>Nostoc</i> Genus of cyanobacteria

Nostoc, also known as star jelly, troll's butter, spit of moon, fallen star, witch's butter, and witch's jelly, is the most common genus of cyanobacteria found in a variety of both aquatic and terrestrial environments that may form colonies composed of filaments of moniliform cells in a gelatinous sheath of polysaccharides. It may also grow symbiotically within the tissues of plants, providing nitrogen to its host through the action of terminally differentiated cells known as heterocysts. Nostoc is a genus that includes many species that are diverse in morphology, habitat distribution, and ecological function. Nostoc can be found in soil, on moist rocks, at the bottom of lakes and springs, and rarely in marine habitats. It may also be found in terrestrial temperate, desert, tropical, or polar environments.

<span class="mw-page-title-main">Nostocaceae</span> Family of bacteria

The Nostocaceae are a family of cyanobacteria that forms filament-shaped colonies enclosed in mucus or a gelatinous sheath. Some genera in this family are found primarily in fresh water, while others are found primarily in salt water. Other genera may be found in both fresh and salt water. Most benthic algae of the order Nostocales belong to this family.

<i>Vicia villosa</i> Species of legume

Vicia villosa, known as the hairy vetch, fodder vetch or winter vetch, is a plant native to some of Europe and western Asia. It is a legume, grown as a forage crop, fodder crop, cover crop, and green manure. Although non-native, it occurs in all US states and is considered invasive by some states, such as Alaska, Florida, Georgia, Kansas, Michigan, Minnesota, Oregon, and Washington state — as well as in Japan and some parts of Europe where it is not native. It is also found in most Canadian provinces.

Water fern is a common name for several plants and may refer to:

<i>Azolla cristata</i> Species of aquatic plant

Azolla cristata , the Carolina mosquitofern, Carolina azolla or water velvet, is a species of Azolla native to the Americas, in eastern North America from southern Ontario southward, and from the east coast west to Wisconsin and Texas, and in the Caribbean, and in Central and South America from southeastern Mexico (Chiapas) south to northern Argentina and Uruguay.

Cyanobionts are cyanobacteria that live in symbiosis with a wide range of organisms such as terrestrial or aquatic plants; as well as, algal and fungal species. They can reside within extracellular or intracellular structures of the host. In order for a cyanobacterium to successfully form a symbiotic relationship, it must be able to exchange signals with the host, overcome defense mounted by the host, be capable of hormogonia formation, chemotaxis, heterocyst formation, as well as possess adequate resilience to reside in host tissue which may present extreme conditions, such as low oxygen levels, and/or acidic mucilage. The most well-known plant-associated cyanobionts belong to the genus Nostoc. With the ability to differentiate into several cell types that have various functions, members of the genus Nostoc have the morphological plasticity, flexibility and adaptability to adjust to a wide range of environmental conditions, contributing to its high capacity to form symbiotic relationships with other organisms. Several cyanobionts involved with fungi and marine organisms also belong to the genera Richelia, Calothrix, Synechocystis, Aphanocapsa and Anabaena, as well as the species Oscillatoria spongeliae. Although there are many documented symbioses between cyanobacteria and marine organisms, little is known about the nature of many of these symbioses. The possibility of discovering more novel symbiotic relationships is apparent from preliminary microscopic observations.

<span class="mw-page-title-main">Biofertilizer</span> Substance with micro-organisms

A biofertilizer is a substance which contains living micro-organisms which, when applied to seeds, plant surfaces, or soil, colonize the rhizosphere or the interior of the plant and promotes growth by increasing the supply or availability of primary nutrients to the host plant. Biofertilizers add nutrients through the natural processes of nitrogen fixation, solubilizing phosphorus, and stimulating plant growth through the synthesis of growth-promoting substances. The micro-organisms in biofertilizers restore the soil's natural nutrient cycle and build soil organic matter. Through the use of biofertilizers, healthy plants can be grown, while enhancing the sustainability and the health of the soil. Biofertilizers can be expected to reduce the use of synthetic fertilizers and pesticides, but they are not yet able to replace their use. Since they play several roles, a preferred scientific term for such beneficial bacteria is "plant-growth promoting rhizobacteria" (PGPR).

<i>Azolla pinnata</i> Species of aquatic plant

Azolla pinnata is a species of fern known by several common names, including mosquitofern, feathered mosquitofern and water velvet. It is native to much of Africa, Asia and parts of Australia. It is an aquatic plant, it is found floating upon the surface of the water. It grows in quiet and slow-moving water bodies because swift currents and waves break up the plant. At maximum growth rate, it can double its biomass in 1.9 days, with most strains attaining such growth within a week under optimal conditions.

<i>Nostoc punctiforme</i> Species of bacterium

Nostoc punctiforme is a species of filamentous cyanobacterium. Under non-limiting nutritional environmental conditions, its filaments are composed of photosynthetic vegetative cells; upon nutrient limitation, some of these cells undergo differentiation into heterocysts, akinetes or hormogonia.

<i>Azolla mexicana</i> Species of aquatic plant

Azolla mexicana, the Mexican mosquito fern, is an aquatic fern native to Mexico, British Columbia and the western United States.

<i>Azolla nilotica</i> Species of aquatic plant

Azolla nilotica is a medium-sized floating fern, that naturally occurs in the Nile and in eastern and central Africa. It is assigned to the family Salviniaceae.

References

  1. Lamarck JB (1783). "Name - Azolla Lam". Encyclopédie Méthodique, Botanique. Saint Louis, Missouri: Missouri Botanical Garden. 1 (1): 343. Archived from the original on October 19, 2012. Retrieved February 19, 2010. Annotation: a sp. nov. reference for Azolla filiculoides
    Type Specimens HT: Azolla filiculoides
  2. 1 2 Hussner A (2006). "NOBANIS -- Invasive Alien Species Fact Sheet -- Azolla filiculoides" (PDF). Online Database of the North European and Baltic Network on Invasive Alien Species. Heinrich Heine University, Düsseldorf. Archived (PDF) from the original on June 23, 2007. Retrieved February 19, 2010.
  3. "Tropicos". Archived from the original on 2014-02-23. Retrieved 2014-02-06.
  4. Azolla filiculoides (water fern) - Invasive Species Compendium https://www.cabi.org/isc/datasheet/8119 Archived 2022-01-19 at the Wayback Machine
  5. Brouwer P, Bräutigam A, Buijs VA, Tazelaar AO, van der Werf A, Schlüter U, et al. (2017-03-31). "Azolla Ferns without Nitrogen Fertilizer". Frontiers in Plant Science. 8: 442. doi: 10.3389/fpls.2017.00442 . PMC   5374210 . PMID   28408911.
  6. Meeks JC (2009). "Physiological Adaptations in Nitrogen-fixing Nostoc–PlantSymbiotic Associations". In Pawlowski K (ed.). Prokaryotic Symbionts in Plants. Microbiology Monographs. Vol. 8. Berlin, Heidelberg: Springer. pp. 181–205. doi:10.1007/7171_2007_101. ISBN   978-3-540-75460-2.
  7. 1 2 "Can A Tiny Fern Help Fight Climate Change and Cut Fertilizer Use?". Yale E360. 2018-07-11. Archived from the original on 2020-10-24. Retrieved 2021-09-27.
  8. Li FW, Brouwer P, Carretero-Paulet L, Cheng S, de Vries J, Delaux PM, et al. (July 2018). "Fern genomes elucidate land plant evolution and cyanobacterial symbioses". Nature Plants. 4 (7): 460–472. doi:10.1038/s41477-018-0188-8. PMC   6786969 . PMID   29967517.
  9. Evrard C, Van Hove C (2004). "Taxonomy of the American Azolla Species (Azollaceae): A Critical Review". Systematics and Geography of Plants. 74 (2): 301–318.
  10. A., Lumpkin, T. (1982). Azolla as a green manure use and management in crop production. Westview Press. ISBN   0-89158-451-X. OCLC   708561329. Archived from the original on 2022-03-27. Retrieved 2021-03-21.{{cite book}}: CS1 maint: multiple names: authors list (link)
  11. Azolla filiculoides (water fern) - Invasive Species Compendium https://www.cabi.org/isc/datasheet/8119 Archived 2022-01-19 at the Wayback Machine
  12. Hussner, Andreas (2010-10-25). "Azolla filiculoides". NOBANIS – Invasive Alien Species Fact Sheet. Archived from the original on 2022-03-27. Retrieved 2021-06-02 via Researchgate.

Further reading