This site requires Javascript to be turned on. Please enable Javascript and reload the page.

Plants & People: The Intersection of Botany and Human Experience

Mankai: The Super Small Superfood

Nomenclatural History

Wolffia globosa (Roxburgh) Hartog & Plas, commonly known as mankai, Asian watermeal, and duckweed, is an aquatic flowering plant. William Roxburgh originally named the specimen Lemna globosa in 1832. However, den Hartog and van der Plas transferred it to the genus Wolffia in 1970. Long before it was assigned a binomial name, mankai was referred to as “Khai nam” by the indigenous people of Thailand (Armstrong, 2021). According to Elias Landholt, the original type specimen seen by Roxburgh could not be found in any of the five herbaria where specimens discovered by Roxburgh are predominantly located (Landholt, 2022). Samples of Wolffia globosa were subsequently collected in West Bengal, where it is believed that Roxburgh collected the original specimen, and studied as a neotype for this reason (Landholt, 2022).

Evolutionary History

Clade Auctor eu augue ut lectus arcu. Integer malesuada nunc vel risus commodo viverra maecenas. Eleifend donec pretium vulputate sapien nec sagittis aliquam malesuada bibendum. Proin sagittis nisl rhoncus mattis rhoncus urna neque. Purus gravida quis blandit turpis cursus in. A erat nam at lectus urna duis convallis. Duis tristique sollicitudin nibh sit. Est velit egestas dui id ornare arcu odio ut sem. Nisl nunc mi ipsum faucibus vitae aliquet nec. Sed enim ut sem viverra aliquet eget. Erat pellentesque adipiscing commodo elit at imperdiet dui accumsan. In nisl nisi scelerisque eu ultrices vitae auctor. Laoreet suspendisse interdum consectetur libero id faucibus nisl tincidunt. Venenatis lectus magna fringilla urna porttitor. Semper quis lectus nulla at volutpat diam ut venenatis tellus. In fermentum posuere urna nec tincidunt. Sed tempus urna et pharetra.

Ecology and Life History

Auctor eu augue ut lectus arcu. Integer malesuada nunc vel risus commodo viverra maecenas. Eleifend donec pretium vulputate sapien nec sagittis aliquam malesuada bibendum. Proin sagittis nisl rhoncus mattis rhoncus urna neque. Purus gravida quis blandit turpis cursus in. A erat nam at lectus urna duis convallis. Duis tristique sollicitudin nibh sit. Est velit egestas dui id ornare arcu odio ut sem. Nisl nunc mi ipsum faucibus vitae aliquet nec. Sed enim ut sem viverra aliquet eget. Erat pellentesque adipiscing commodo elit at imperdiet dui accumsan. In nisl nisi scelerisque eu ultrices vitae auctor. Laoreet suspendisse interdum consectetur libero id faucibus nisl tincidunt. Venenatis lectus magna fringilla urna porttitor. Semper quis lectus nulla at volutpat diam ut venenatis tellus. In fermentum posuere urna nec tincidunt. Sed tempus urna et pharetra.

Morphological Description of Vegetative Attributes

Morphological Description of Reproductive Attributes

While Mankai have undergone a simplification of their vegetative attributes from Spirodela to Wolffia, their reproductive attributes have stayed relatively the same, only changing in size to accommodate the smaller plant. Mankai propagate through vegetative reproduction, which is a type of asexual reproduction. As mankai are autogamous, the parent plant contains both a stigma and a stamen. The parent also contains a basal reproductive pouch where daughter fronds will grow upon fertilization (Armstrong, 2021). Parent plants reproduce exponentially through budding, and, under optimal conditions, are able to double their mass in roughly 48 hours (Yang et al., 2021). As mankai reproduce from November to July, their rapid growth rate and overall hardiness suggest that they could potentially be a sustainable form of plant-based protein that could be used to combat food insecurity (European Food Safety Authority, 2021).

Historical Accounts

Libero nunc consequat interdum varius sit amet mattis vulputate. Fringilla est ullamcorper eget nulla. Convallis convallis tellus id interdum. Mauris pharetra et ultrices neque ornare. Nunc vel risus commodo viverra maecenas accumsan lacus vel facilisis. Sit amet mauris commodo quis imperdiet massa tincidunt nunc pulvinar. A erat nam at lectus urna duis convallis convallis. Pharetra massa massa ultricies mi quis hendrerit dolor magna. Adipiscing enim eu turpis egestas pretium aenean pharetra magna ac. Facilisi etiam dignissim diam quis. Libero id faucibus nisl tincidunt eget nullam.

Domestication History

Ante in nibh mauris cursus mattis molestie. Ullamcorper malesuada proin libero nunc. Mauris a diam maecenas sed enim ut sem. Interdum velit euismod in pellentesque massa placerat duis ultricies lacus. Leo duis ut diam quam. Orci dapibus ultrices in iaculis nunc sed augue lacus. Etiam non quam lacus suspendisse faucibus interdum. Habitant morbi tristique senectus et netus et malesuada fames. Neque egestas congue quisque egestas diam. Lectus nulla at volutpat diam. In hac habitasse platea dictumst quisque sagittis purus sit amet. Velit scelerisque in dictum non consectetur a erat. At consectetur lorem donec massa sapien faucibus et molestie.

Cultivation Practices

Mankai grows on the surface of calm freshwater bodies of water such as ponds, lakes, and marshes. It is native many countries throughout Asia, including Thailand, Laos, India, China, Indonesia, and Myanmar. It can also be found growing natively in Hawaii and California, where it was discovered by W.P. Armstrong, nicknamed “Mr. Wolffia,” in 1984. Due to its rapid growth rate, Mankai is only harvested, not cultivated, by indigenous peoples living in the aforementioned Asian countries. The yearly harvest takes place twice a week from November to July (European Food Safety Authority, 2021). Nets are typically used to collect the mankai from the surface of the water. The recent commercialization of mankai has led to the utilization of aquatic farms and vertical farming, both of which utilize fertilizer, to cultivate mankai on a larger scale. According to the European Food Safety Authority (EFSA), the composition of mankai grown through vertical farming actually does differ from the composition of mankai in natural ponds. However, the EFSA concluded that these slight differences in nutritional value do not raise safety concerns regarding human consumption of mankai that is cultivated through vertical farming (European Food Safety Authority, 2021).

Nutritional Value

Mankai has recently become popular in the western world due to its nutritional benefits. The entire plant is consumed. Although it can be eaten raw, it is traditionally cooked before consumption. According to a study on the protein bioavailability of mankai conducted by Kaplan et al. in 2019, Mankai contains all nine essential amino acids, namely histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine, dietary fibers, polyphenols, which help to manage blood pressure levels, iron, zinc, and vitamin B12, which is important for keeping blood and nerve cells healthy (Kaplan et al., 2019). Furthermore, as mankai is more than 45% protein, when measuring by dry weight, it is currently emerging as a new substitute to animal-based protein sources (Kaplan et al., 2019).

Human Experience

References

Armstrong, W. P. (2021, July 4). Wayne Armstrong’s Treatment of the Lemnaceae. Palomar College. Retrieved May 26, 2022, from https://www2.palomar.edu/users/warmstrong/1wayindx.htm

Bog, M., Appenroth, K. J., & Sree, K. S. (2019). Duckweed (Lemnaceae): Its Molecular
Taxonomy. Frontiers in Sustainable Food Systems, 3. https://doi.org/10.3389/fsufs.2019.00117

Klaus, J. A., Nikolai, B., & Eric, L. (2013). Telling Duckweed Apart: Genotyping Technologies for the Lemnaceae. Chinese Journal of Applied Environmental Biology, 19(1), 1–10. https://doi.org/10.3724/sp.j.1145.2013.00001

Pagliuso, D. (2018, July 20). Correlation of Apiose Levels and Growth Rates in Duckweeds. Frontiers. Retrieved May 25, 2022, from https://www.frontiersin.org/articles/10.3389/fchem.2018.00291/full

Technical Report on the notification of fresh plants of Wolffia arrhiza and Wolffia globosa as a traditional food from a third country pursuant to Article 14 of Regulation (EU) 2015/2283. (2021). EFSA Supporting Publications, 18(6). https://doi.org/10.2903/sp.efsa.2021.en-6658

Wang, W., Kerstetter, R. A., & Michael, T. P. (2011). Evolution of Genome Size in Duckweeds (Lemnaceae). Journal of Botany, 2011, 1–9. https://doi.org/10.1155/2011/570319

Yang, J., Hu, S., Li, G., Khan, S., Kumar, S., Yao, L., Duan, P., & Hou, H. (2020). Transformation Development in Duckweeds. The Duckweed Genomes, 143–155. https://doi.org/10.1007/978-3-030- 11045-1_15

Yang, J., Zhao, X., Li, G., Hu, S., & Hou, H. (2021). Frond architecture of the rootless duckweed Wolffia globosa. BMC Plant Biology, 21(1). https://doi.org/10.1186/s12870-021-03165-5