Today is World Wetlands Day https://www.worldwetlandsday.org/ and my subject this week is duckweed. Duckweedsare aqueous plants that constitute the Lemnaceae family in the monocots clade that includes grasses, palms and lilies,. They are thus unrelated tonon-monocot water plants like lotus (Nelumbonaceae, eudicot) or waterlily (Nymphaeaceae, not a lily).
The duckweed genera (Lemna, Spirodela, Wolffia, Wolffiella) grow asfloating fronds, propagating vegetatively by producing daughter fronds that bud off and separate. Under rare circumstances the plants will produce tiny flowers
Spirodela is of personal significance as I used it for my doctoral research to study protein metabolism. Ideally suited for this research, it happily drinks tracer molecules and inhibitors. Because of their thirst for chemicals, duckweeds can be incorporated in permaculture systems to denitrify and recycle the waste water from fish farming. They can also be used for phytoremediation(https://lnkd.in/dXCH3fP9) of contaminated water.
Duckweed is nutritious, with vitamins, minerals and healthy oils as in other green vegetables, and high-quality protein mostly from the RubisCO enzyme that otherwise serves in photosynthetic CO₂ fixation. Duckweed doesn’t sufferswater stress, so produces less stress-induced secondary phytochemicals thanland-based plants. Nevertheless, Spirodela polyrhizza appears in Chinese Pharmacopoeiaas Fuping (浮萍). It has been used in experimental herbal treatments for COVID-19 (Dong et al, 2022) and in “detoxification” therapy for atopic dermatitis. I withhold judgement efficacy of these therapies.
Evolution sometimes proceeds rapidly, particularly evolution of scientific classifications. The Lemnacae family has now been demoted to a subfamily, the Lemnoide, within the Araceae family that also includes land plants. Furthe rmore,the Spirodela species I used for my doctoral research is now reclassified as Landoltiapunctata, with a newly created genus intermediate between Spirodela and Lemna. The plants themselves are unimpressed with these reclassifications.
Further reading
🦆 Baek G et al (2021). Duckweeds: their utilization, metabolites and cultivation. Applied biological chemistry, 64(1), 73. https://doi.org/10.1186/s13765-021-00644-z
🦆 Dong Y et al (2022). A retrospective study of Pupingqinghua prescription versus Lianhuaqingwen in Chinese participants infected withSARS-CoV-2 Omicron variants. Frontiers in pharmacology, 13,988524. https://doi.org/10.3389/fphar.2022.988524
🦆 Kim, K. S., & Nam, H. J. (2013).Detoxification combining fasting with fluid therapy for refractory cases ofsevere atopic dermatitis. Evidence-based complementary and alternativemedicine : eCAM, 2013, 561290.https://doi.org/10.1155/2013/561290
