Native Growth and Conservation of Duckweed (Lemnaceae) in Jordan

Background and objectives: Duckweeds are the world's smallest flowering plants. Its existence is affected by the water quality and availability. The increased water demand and water scarcity in most of the Mediterranean countries as Jordan have caused remarkable lowering in the water-table which reduced floods and disappearance of the seasonal lakes. Due to this, aquatic plants that grow on good quality of fresh water have disappeared totally. Therefore, this paper highlights the native growth and conservation of duckweed (Lemnaceae) in Jordan. It also focuses on the identification of water sources for duckweed's movement.

Materials and methods: Field surveys were conducted to identify water source for water bodies that contain duckweeds. These surveys included visits to the Zarqa river, dams, irrigation ponds and Jordan valley. The source of water for duckweed movement and availability was determined. Water samples from the targeted areas were analyzed for selected parameters as pH, EC, NO3, PO4, BOD5, Zn, Pb, Cd and Cu.

Results: The results showed that King Abdullah Canal and Zarqa river are the water sources that encourage the duckweeds growth. In Sukhnah, Jerash and Jordan valley areas, water analysis ranges (mg L-1) are: NO3 0.7-38, PO4 0.3-7.6 and BOD5 0-20. The pH range value is 7.1-8.1 and EC range value is 1.62-2.5 mS cm-1.The heavy metals values are, Zn is <0.02 mg L-1, Pb is <0.01 mg L-1, Cd is <0.002 mg L-1 and Cu is <0.01 mg L-1.

Conclusion: It can be concluded that mitigation measures are highly needed to overcome and altering the quality of the natural water flowing and participation of governmental institutions is also required for the success of applying mitigation measures to preserve the aquatic plants.