Lemna sp. Growth Inhibition Test (OECD TG 221)
The Lemna sp. Growth Inhibition Test according to OECD TG 221 is used to assess the toxic effects of substances on aquatic macrophytes. Lemna species (commonly known as duckweed) are floating freshwater plants that play an important role as primary producers in aquatic ecosystems.
In this test, rapidly growing Lemna colonies are exposed to a range of concentrations of the test substance under controlled laboratory conditions for a period of typically 7 days. Growth is monitored by measuring parameters such as frond number, frond area, and biomass (fresh or dry weight).
The objective is to establish concentration–response relationships and to determine key endpoints, including the median effective concentration (ErC₅₀ or EyC₅₀) and the No Observed Effect Concentration (NOEC).
This test provides essential information on the potential impact of chemicals on aquatic plant life and primary productivity, supporting environmental risk assessment and regulatory decision-making.
