Duckweed forms one of the most territorially aggressive groups of aquatic vegetation and varieties include giant duckweed, dotted duckweed and watermeal. The group's diverse adaptations allow it to easily out-compete other types of pond weeds, especially submersed plants growing up from the bottom.
Duckweed has flexible leaves to reach higher and absorb more sunlight. It also utilizes large air pockets in its cells, in addition to tiny hairs that trap additional air used for flotation.
Leaves are usually broad and flat. making them ideal for sitting on the water surface. Because their chloroplasts--parts of the plant cells that conduct photosynthesis--are located on top of these leaves, duckweeds maximize surface area and make use of full and direct sunlight.
In an aquatic ecosystem, duckweeds inherently absorb more sunlight than submerged plants, sometimes even shading out their underwater counterparts. However, they still compete with one-another, as leaves can overlap in dense communities.
The pores used for gas exchange of carbon dioxide and oxygen are open most of the time because water is plentiful and there is no need for it to be retained in the plant. The plant conserves energy because "guard cells" around the stomata are inactive due to not having to constantly open and close the pores.
Because it is the leafy part of the plant that keeps it afloat, the root system incurs no strain on supporting the plant. Therefore, a feathery and relatively weak root system hangs from the leaf and suffices for food uptake.
- University of Florida Center for Aquatic and Invasive Plants
- UCLA Botanical Gardens: Aquatic Plants
- WVU Extension: Guide To Aquatic and Wetland Plants of West Virginia
duckweed, watermeal, duckweed adaptations