Lemna minor
| Lenna minor | |
|---|---|
 |
|
| Scientific classification | |
| Kingdom: | Plantae |
| (unranked): | Angiosperms |
| (unranked): | Monocots |
| Order: | Alismatales |
| Family: | Araceae |
| Subfamily: | Lemnoideae |
| Tribe: | Lemneae |
| Genus: | Lemna |
| Species: | L. minor |
| Binomial name | |
| Lemna minor L. |
|
Lenna minor (Common Duckweed or Lesser Duckweed) is a species of Lenna (duckweed) with a subcosmopolitan distribution, native throughout most of Africa, Asia, Europe and North America, occurring everywhere that freshwater ponds and slow-moving streams occur, except for arctic and subarctic climates. It is not reported as native in Australasia or South America, though is naturalised there.[1][2]
It is a floating freshwater aquatic plant, with one, two or three leaves each with a single root hanging in the water; as more leaves grow, the plants divide and become separate individuals. The root is 1-2 cm long. The leaves are oval, 1-8 mm long and 0.6-5 mm broad, light green, with three (rarely five) veins, and small air spaces to assist flotation. It propagates mainly by division, and flowers are rarely produced; when produced, they are about 1 mm diameter, with a cup-shaped membranous scale containing a single ovule and two stamens. The seed is 1 mm long, ribbed with 8-15 ribs.[3][4][5]
It grows in water with high nutrient levels and a pH of between 5 and 9, optimally between 6.5 and 7.5, and temperatures between 6 and 33 °C.[6] Growth of colonies is rapid, and the plant frequently forms a complete carpet across still pools when conditions are suitable. In temperate regions, when temperatures drop below 6 to 7 °C it develops small, dense, starch-filled organs called 'turions', which become dormant and sink to the water bottom for winter; the following spring, these recommence growth and float back to the surface.[6][7]
It is an important food resource for many fish and birds (notably ducks); it is rich in protein and fats.[6] Birds are also important in dispersing the species to new sites; the root is sticky, enabling the plant to adhere to the plumage or feet while the bird flies from one pond to another.[8]
[edit] Cultivation and uses
It is often used as a plant in both coldwater and tropical aquaria as well as in outdoor ponds, though it must be frequently cut back because of its rapid growth rate and may be considered a pest.[9] It is also grown as a commercial crop for animal feed, primarily for fish and poultry, as it is fast-growing and easy to harvest by surface skimming.[6]
[edit] Population and Competition
Lemna minor is structurally adapted to grow quickly. That enables it to populate bodies of water rapidly. It overcomes inter-species competition by growing a thick carpet over still water bodies, thereby shading out other plant species below it and eliminating the competition. With intra-specific competition, it will compete by absorbing as much of its surrounding resources as possible so that it has the energy to grow and reproduce.
[edit] References
- ^ Germplasm Resources Information Network: Lemna minor
- ^ Den Virtuella Floran: Northern Hemisphere map
- ^ Flora of NW Europe: Lemna minor
- ^ Flora of North America: Lemna minor
- ^ Plants of British Columbia: Lemna minor
- ^ a b c d FAO: Duckweed - a potential high-protein feed resource for domestic animals and fish
- ^ Lemna minor
- ^ Missouri Botanical Garden: Duckweed Roots
- ^ Hiscock, P. (2003). Encyclopedia of Aquarium Plants. United States and Canada: Interpret Publishing. ISBN 0-7641-5521-0.
