Adapted from an excellent review on media for in vitro-cultivation by Klaus-J. Appenroth (see the 11th issue of Duckweed Forum)
There is a large number of cultivation media in use for duckweed. This simply shows that most duckweed can adapt to a broad range of conditions. This does not mean that physiological responses are always the same. In order to support scientific standards for the duckweed community, we (Klaus-J. Appenroth) compiled the most useful nutrient media here in form of lab protocols, including the stock solutions used. All protocols are for autotrophic cultivation.
If mixotrophic cultivations are required, either glucose (50 mM) or sucrose (25 mM) should be added. We have never added vitamins or other organics as green plants produce it themselves.
Final concentrations are given in molar concentrations – and should be given in scientific publications. Only then different nutrient media can be compared and the data do not depend e.g. on the amount of crystal water of the substances.
Most of the original protocols were published before FeEDTA or FeNaEDTA were available on a commercial basis. In most cases, these substance are much easier to handle than other sources of iron. Only when possible chelating effects may have an influence on the physiological effects under investigation (e.g. flowering) one should take care.
All nutrient media should be autoclaved before use. The numbers in brackets are the molecular weight in g/mol, which might help in calculations.
Please refer to the 11th issue of Duckweed Forum for recipes of commonly used cultivation media.