Lemnoideae
Lemnoideae | |
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Close-up of two different duckweed types: Spirodela polyrrhiza and Wolffia globosa : The latter are less than 2 mm long.
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Scientific classification | |
Kingdom: | Plantae |
Clade: | Tracheophytes |
Clade: | Angiosperms |
Clade: | Monocots |
Order: | Alismatales |
Family: | Araceae |
Subfamily: | Lemnoideae |
Genera | |
Synonyms | |
Lemnaceae |
Lemnoideae is a subfamily of flowering
so often are classified as the subfamily Lemnoideae within the family Araceae. Other classifications, particularly those created prior to the end of the twentieth century, place them as a separate family, Lemnaceae.These plants have a simple structure, lacking an obvious
Reproduction is mostly by
The flower of the duckweed genus
Duckweed in natural environments
One of the more important factors influencing the distribution of wetland plants, and aquatic plants in particular, is nutrient availability.[4] Duckweeds tend to be associated with fertile, even eutrophic conditions. They can be spread by waterfowl and small mammals, transported inadvertently on their feet and bodies,[5] as well as by moving water. In water bodies with constant currents or overflow, the plants are carried down the water channels and do not proliferate greatly. In some locations, a cyclical pattern driven by weather patterns exists in which the plants proliferate greatly during low water-flow periods, then are carried away as rainy periods ensue.
Duckweed is an important high-
Use as human food crop
Duckweed is consumed in some parts of Southeast Asia, namely Laos, Thailand, and Myanmar.[6] In addition, it is also cultivated as a vegetable in Israel.[7] It produces more protein per square meter than soybeans, so sometimes it is cited as a significant potential food source.[8]
Some initial investigations to what extent duckweed could be introduced in European markets show little consumer objection to the idea.[9] NASA's Caves of Mars Project identified duckweed as a top candidate for growing food on Mars.[10]
Invasive species
Despite some of these benefits, because duckweed thrives in high-nutrient wetland environments, the plants can be seen as a nuisance species when conditions favor excessive proliferation in environments that are traditionally low in nutrients or
One example of this problem occurs within the Everglades, a mostly oligotrophic environment, when excess chemicals (that include fertilizers) are carried by storm runoff, or surface runoff, into its waterways.[11]
Taxonomy
The duckweeds have long been a taxonomic mystery, and usually have been considered to be their own family, the Lemnaceae. They primarily reproduce asexually. Flowers, if present at all, are small. Roots are either very much reduced, or absent entirely. They were suspected of being related to the Araceae as long ago as 1876, but until the advent of
Starting in 1995, studies began to confirm their placement in the Araceae and since then, most systematists consider them to be part of that family.[13]
Their position within their family has been slightly less clear; however, several twenty-first century studies place them in the position shown below.[13] Although they are in the same family as Pistia, another aquatic plant, they are not closely related.[13]
Araceae |
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The
.Duckweed
To identify different duckweed genomes, a DNA-based molecular identification system was developed based on seven plastid-markers proposed by the Consortium for the Barcode of Life.[16] The atpF-atpH non-coding spacer was chosen as a universal DNA barcoding marker for species-level identification of duckweeds.[17]
Fossil record
Extinct free-floating aquatic plants and pollen with affinities to the Lemnoideae first appear in the fossil record during the Late Cretaceous (Maastrichtian) as evidenced by floating leaves described as Aquaephyllum auriculatum from Patagonia, Argentina, and the lemnoid pollen genus Pandaniidites.[18]
Fossils of floating leaves with rootlets from the
Research and applications
Research and applications of duckweeds are promoted by two international organizations, The International Lemna Association[21] and the International Steering Committee on Duckweed Research and Applications.[22]
In July 2008, the
Potential clean energy source
Duckweed is being studied by researchers around the world as a possible source of clean energy. In the U.S., in addition to being the subject of study by the DOE, both
Filtration of contaminants and nutrients
The plants can provide
The Swiss Department of Water and Sanitation in Developing Countries, associated with the Swiss Federal Institute for Environmental Science and Technology, asserts that as well as the food and agricultural values, duckweed also may be used for
These plants also may play a role in conservation of water because a cover of duckweed will reduce evaporation of water when compared to the rate of a similarly sized water body with a clear surface.
Duckweed also functions as a bioremediator by effectively filtering contaminants such as bacteria, nitrogen, phosphates, and other nutrients from naturally occurring bodies of water, constructed wetlands, and wastewater.[35][36][37]
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Common duckweed in Galicia, Spain
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Duckweed-covered water edged with severalbald cypresstrees
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Myllylampi lake with duckweed "islands" photographed from above. Orusjärvi, Pitkyarantsky District, Karelia, Russia.
A start-up, microTERRA, based in Mexico has attempted to use duckweed as clean water in privately owned aquaculture farms. The plants use nitrogen and phosphorus produced from fish waste as fertilizer, while simultaneously cleaning the water as it grows. The water can then be reused by the aquaculture farmers, and the duckweed, which has a 35-42% protein content, can be harvested as a source of sustainable protein.[38]
See also
References
- PMID 21653404.
- ISBN 978-3-87429-257-3.
- ^ Landolt, Elias (1986). Biosystematic investigations in the family of duckweeds (Lemnaceae) Vol. 2: The family of Lemnaceae: a monographic study. – Morphology, karyology, ecology, geographic distribution, nomenclature, descriptions. Zürich: Eidgenössische Technische Hochschule Zürich.
- ISBN 978-0-521-73967-2. Retrieved 7 May 2012.
- ^ Hutchinson, G. Evelyn (1975). A Treatise on Limnology. Vol. 3: Limnological botany. New York, NY: John Wiley & Sons.
- S2CID 6617534.
- ^ "Lemna Gibbous Duckweed, Swollen duckweed, Windbags, Duckweed PFAF Plant Database". pfaf.org. Retrieved 4 January 2023.
- ^ Landesman, Louis. "Dr. Wastewater's duckweed application page". Archived from the original on 27 October 2009. Retrieved 31 January 2012.
- .
- ^ "Flat crops for Mars". The caves of Mars (highmars.org). Archived from the original on 1 July 2007. Retrieved 11 January 2022.
- ISBN 9781259255724.
- ISBN 9783319561783. Retrieved 1 January 2021.
- ^ a b c
Cabrera, Lidia I.; Salazar, Gerardo A.; Chase, Mark W.; Mayo, Simon J.; Bogner, Josef; Dávila, Patricia (2008). "Phylogenetic relationships of aroids and duckweeds (Araceae) inferred from coding and noncoding plastid DNA". PMID 21632433.
- ISSN 2090-0120.
- PMID 21931804.
- PMID 19666622. Retrieved 2 August 2012.
- PMID 20846439.
- hdl:11336/36506.
- ^ .
- S2CID 20957240.
- ^ "The International Lemna Association (ILA)" (official website).
- ^ "International Steering Committee on Duckweed Research and Applications (ISCDRA)" (official website).
- ^ "Duckweed genome sequencing has global implications". E! Science News (Esciencenews.com). 8 July 2008. Retrieved 13 November 2011.
- PMID 24548928.
- ^ Michael, Todd P. (2008). "Genome sequencing of the duckweed Spirodela polyrhiza: A biofuels, bioremediation, and carbon cycling crop" (PDF). Rutgers University. Archived from the original (PDF) on 3 October 2011. Retrieved 7 May 2012.
- ^ "Researchers Find Fuel in Odd Places". Ncsu.edu. Retrieved 13 November 2011.
- ^ Sims, Bryan (n.d.). "Duckweed quacks volumes of potential". Biomassmagazine.com. Retrieved 13 November 2011.
- ^ "Duckweed a possible solution to energy needs, researchers say". Pressofatlanticcity.com. 3 May 2010. Retrieved 13 November 2011.
- PMID 33424309.
- ISSN 1435-8603.
- ISSN 2352-1864.
- ^ "Carbon Neutral Energy". American Energy Independence. Retrieved 13 November 2011.
- ^ "Duckweed wastewater treatment and reuse for fodder (West Bank)". Idrc.ca. Archived from the original on 8 June 2011. Retrieved 13 November 2011.
- ^ Iqbal, Sascha (March 1999). "Duckweed aquaculture: Potentials, possibilities, and limitations for combined wastewater treatment and animal feed production in developing countries" (PDF). SANDEC Report. 6 (99). Retrieved 31 January 2012.
- ^ "Duckweed genome sequencing has global implications. Pond scum can undo pollution, fight global warming and alleviate world hunger" (Press release). Rutgers University. 8 July 2008. Retrieved 10 March 2022.
- ^ Cross, John W. "Practical duckweed: Application areas and sponsors". Mobot.org. Retrieved 13 November 2011.
- ^ Knibb, Wayne (July 2001 – June 2004). "Bioremediation of aquaculture waste and degraded waterways using finfish". Department of Primary Industries & Fisheries Tools. Australia: Queensland Government. Archived from the original on 20 October 2007. Retrieved 6 February 2012.
- ^ "3 Eco-Innovators Tackling Pollution and Climate Change". Columbia Magazine. Retrieved 24 November 2021.
External links
- Cross, John W. "The charms of duckweed". mobot.org.
- Armstrong, Wayne (n.d.). "W.P. Armstrong's exposition on and macrophotography of the Lemnaceae and allies (duckweeds)". Wayne's Word. Natural History. San Marcos, CA: Palomar College. Retrieved 16 October 2022.
- "Lemnaceae". delta-intkey.com.
- derived from
- Watson, L. & Dallwitz, M.J. (3 May 2006) [1992]. The Families of Flowering Plants: Descriptions, illustrations, identification, information retrieval. Archived from the original on 3 January 2007 – via delta-intkey.com.
- "Duckweed growth inhibition test". List of Standards. lemnatec.com. Archived from the original on 27 January 2013.
- "Spirodela genomics" (research lab site). SpirodelaBase. Rutgers University.