Flowering and seed production across the lemnaceae

Authors: FOUROUNJIAN, PAUL - Rutgers University; Slovin, Janet; MESSING, JOACHIM - Rutgers University

Submitted to: International Journal of Molecular Sciences
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/5/2021
Publication Date: 3/8/2021
Citation: Fourounjian, P., Slovin, J.P., Messing, J.W. 2021. Flowering and seed production across the lemnaceae. International Journal of Molecular Sciences. 2021, 22(5), 2733. https://doi.org/10.3390/ijms22052733.
DOI: https://doi.org/10.3390/ijms22052733

Interpretive Summary: Plants in the family Lemnaceae are also known as duckweeds, which grow on top of still waters throughout the world. They are the smallest, simplest, and fastest growing flowering plants, making them ideal for laboratory studies. Their extremely rapid growth rate, and the fact that they have no woody parts, has spurred recent interest in using them as biomass sources for commercial fuel production. They also contain especially nutritious protein composition, making them a cheaply produced food source. Duckweeds are also being investigated as a means of cleaning up wastewater, with the added value that they can be harvested for fuel. We optimized culture conditions to get maximum flowering for the three duckweed types. Flowering is critically important for breeding improved varieties. We screened a large number of different media as well as varying the length of daily light the cultures received, looking for maximum flowering. We also tested the addition of two chemicals known to affect flowering, and tested various culture containers. Our flowering optimized culture conditions will promote further laboratory studies on these unique plants, and form the basis for breeders, both academic and commercial, to develop improved varieties for fuel, food, and for wastewater cleanup.

Technical Abstract: Plants in the family Lemnaceae are aquatic monocots and the smallest, simplest, and fastest growing angiosperms. Their small size, the smallest family member is 0.5 mm and the largest is 2.0 cm, as well as their diverse morphologies make these plants ideal for laboratory studies. This Their rapid growth rate is partially due to the family’s neotenous lifestyle, where instead of maturing and producing flowers, the plants remain in a juvenile state and continuously bud asexually. Maturation and flowering in the wild are rare in most family members. To promote further research on these unique plants, we have optimized laboratory flowering protocols for 3 of the 5 genera: Spirodela; Lemna; and Wolffia in the Lemnaceae. Duckweeds were widely used in the past for research on flowering, hormone and amino acid biosynthesis, the photosynthetic apparatus, and phytoremediation due to their aqueous lifestyle and ease of aseptic culture. There is a recent renaissance in interest in growing these plants as non-lignified biomass sources for fuel production, and as a resource-efficient complete protein source. The genome sequences of several Lemnaceae family members have become available, providing a foundation for genetic improvement of these plants as crops. The protocols for maximizing flowering described herein are based on screens testing daylength, a variety of media, supplementation with salicylic acid or ethylenediamine-N,N'-bis(2-hydroxyphenylacetic acid) (EDDHA), as well as culture vessel on for effects on flowering of verified Lemnacea strains available from the Rutgers Duckweed Stock Cooperative.