The Charms of Duckweed
The family of duckweeds (botanically, the Lemnaceae) are the
smallest flowering plants. These plants grow floating in
still or slow-moving fresh water around
the globe, except in the coldest regions. The growth of these
high-protein plants can be extremely rapid. Lemna is one of the best
known of this group and has been the subject of much
Researchers are using these plants to study basic plant development, plant biochemistry,
photosynthesis, the toxicity
of hazardous substances, and much more. Genetic engineers
are cloning duckweed genes and
modifying duckweeds to inexpensively produce pharmaceuticals.
Environmental scientists are using duckweeds to remove unwanted
substances from water. Aquaculturalists find them an
source for fish farming.
To learn more about these fascinating plants, next read the botanical facts, or view some duckweed illustrations. Read about cloning.
|We wish to honor the memory of the foremost duckweed scholar, Professor Elias Landolt, who died April 1, 2013.|
For the agenda and abstracts, click [ here
]. The presentation slides are available [ here
] The 1st International Conference was held
in Chengdu, China in October 2011. The
presentation slides are still available at [ here
The International Lemna Association (ILA) is a non-profit organization whose mission is to promote the development of commercially-viable markets for renewable and sustainable products derived from duckweed. Its membership consists of people, companies, and organizations across the value chain.
Primary goals of the ILA are to:
Duckweed on Lake Maracaibo, VenezuelaVenezuela struggled to remove aquatic plant faster than it spread over nation's largest lake
Thursday, 17 June 2004 by Alexandra Olson, Associated Press
CARACAS, Venezuela 52; Efforts to remove an aquatic weed from Venezuela's largest lake are barely keeping up with its growth, the environment minister said Wednesday. The green plant, known as duckweed or lemna, covers about 12 percent of Lake Maracaibo's 13,500-square kilometer (5,400-square mile) surface, said Ana Elisa Osorio. The lake in western Venezuela is one of South America's largest bodies of water and is an important oil-producing region....
[ read more ]
A study of the causes of the 2004 invasion of Lake Maracaibo by duckweed and proposals for future action was published in July of that year [ link ]. The Venezuelan government subsequently implemented mechanical skimming to remove this vegetation. By September 2004, 75% of the duckweed had been removed by the mechanical skimmers.
However, the duckweed continues to be a problem on the lake. Satellite imaging for the period 2005-2011 showed an average duckweed coverage of about 1.5% of the almost 13,000 km2 lake, ranging from 0.5% to almost 7% in extreme years. [ reference ]
Above: NASA image of Lake
Maracaibos. Duckweed (Lemna obscura) can be
seen in large swirls across the lake surface.
Philadelphia Inquirer Photo, 08/17/1999
|Read how duckweeds can take over lakes
Left: Duckweeds do not normally grow in
rivers, but a drought in the summer of 1999 reduced the
flow of water into the Schuylkill River in Philadelphia,
Pennsylvania. The reduced flow increased the levels
of nutrients and allowed a duckweed bloom to accumulate in
the channel. After this picture was taken, the
duckweeds gradually were washed away by the current of the
|Notes to students
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Revised: November 30, 2013