The Charms of Duckweed Providing information about the smallest flowering plants since 1998. Hosted by the Missouri Botanical Garden http://www.mobot.org/jwcross/duckweed/duckweed.htm

The family of duckweeds (botanically, the Lemnaceae) are the smallest flowering plants. These plants grow floating in still or slow-moving fresh water around the globe, except in the coldest regions. The growth of these high-protein plants can be extremely rapid. Lemna is one of the best known of this group and has been the subject of much research.

Researchers are using these plants to study basic plant development, plant biochemistry, photosynthesis, the toxicity of hazardous substances, and much more. Genetic engineers are cloning duckweed genes and modifying duckweeds to inexpensively produce pharmaceuticals. Environmental scientists are using duckweeds to remove unwanted substances from water. Aquaculturalists find them an inexpensive feed source for fish farming.

To learn more about these fascinating plants, next read the botanical facts, or view some duckweed

illustrations. Read about cloning….

Creating The Charms of Duckweed, An Educational Website John W. Cross, Ph.D. • Alexandria, VA, USA

Copyright © 2013 John W. Cross

1. People and Events that led me to create The Charms of Duckweed

2. Helping me keep the website current and accurate

Two Themes:

1. People and Events that led me to create The Charms of Duckweed

2. Helping me keep the website current and accurate

Two Themes:

Dr. William S. Hillman (1929– 1981)

Senior Plant Physiologist, Brookhaven National Laboratory, (1962-1981)

Assistant Professor, Yale University,

Ph.D. Yale University

Hillman pioneered basic research on photoperiodic control of flowering in Lemna, “playing a critical role in the study of photomorphogenesis.” Later, he began collaborating with Bud Culley at LSU on applications of duckweeds.

Janet P. Slovin, Ph.D.

Molecular Biologist, Research Plant Physiologist,

Genetic Improvement for Fruits and Vegetables Laboratory, USDA-ARS, Beltsville, MD

“A recognized expert on the Lemnaceae

and on the use of genetic systems to

study plant development.”

Dr. William S. Hillman (1929– 1981)

Senior Plant Physiologist, Brookhaven National Laboratory, (1962-1981)

Assistant Professor, Yale University,

Ph.D. Yale University

Hillman pioneered basic research on photoperiodic control of flowering in Lemna, “playing a critical role in the study of photomorphogenesis.” Late in his life, he began collaborating with Bud Culley at LSU on applications of duckweeds.

Testing Plant Growth Regulators for Phytotoxicity, 1989 - 1994

1989 – 1991 / Sogetal Inc., The University of San Francisco

Counting fronds: Exponential growth of duckweed as the basis of a phytotoxicity bioassay

The average number of fronds per dish is plotted, plus or minus standard deviation. An exponential curve was fit to the averaged data (see box) and is plotted (blue line). The average doubling time for frond number ( t2 ) can be calculated from the exponential constant. In this experiment, t2= ln(2)/0.298 = 2.3 days. http://www.mobot.org/jwcross/duckweed/Lemna_growth/Lemna_growth.htm

1991 – 1994 / EPL Bio-Analytical Services

Prof. Dr. em. Elias Landolt, 1926 – 2013

1926 Born in Zürich, Switzerland

1945-1949 Study of biology at the Swiss Federal Institute of Technology (ETH) in Zürich

1949 MS at Institut für spezielle Botanik ETH

1953 Ph.D at ETH

1953-1955 Postdoctoral studies at Carnegie Lab., Stanford California and Cal. Tech., Pasadena, California

1955-1964 Assistant and lector at Institut für spezielle Botanik ETH

1964 Prof. of Plant Systematics, Institut für spezielle Botanik ETH

1966-1993 Director of Geobotanical Inst., Rübel Foundation, ETH, and Prof. of Geobotany.

Since 1993 Prof. em. at Geobot. Inst., ETH.

http://geofms.ethz.ch:591/Geodyn/Koordinaten/FMPro?-db=Koordinaten&id=41&-format=datensatzdetail_e.htm&-lay=www&-op=eq&-max=1&-find

At a dairy near Baton Rouge, Louisiana, wastes from a milking shed are washed into a neighboring lagoon planted with duckweed (Spirodela spp.). The plants can aid in purifying such lagooned wastewaters by absorbing large quantities of nutrients. In experiments at Louisiana State University duckweeds are being mixed into poultry, swine, and cattle rations to test their suitability as feed ingredients. (D. D. Culley, 1976)

From: Ad Hoc Panel of the Advisory Committee on Technology Innovation, Board on Science and Technology for International Development • Commission. on International Relations, Making Aquatic Weeds Useful: Some Perspectives for Developing Countries, National Academy of Sciences, Washington, 1976, p. 151.

Dudley D. Culley, Jr.

Professor Emeritus, School of Renewable Natural Resources. Louisiana State University

PhD, Mississippi State University.

“A duckweed/dairy farm

Although several uses of duckweed thus seem attractive, none has been fully tested in practice. To introduce some quantitative elements and illustrate some general aspects of the approach, we will describe one possible system in some detail. Figure 2 is an artists concept of a duckweed dairy farm system with an average sized herd of cattle (about 100) encompassing waste treatment, nutrient recycling an deficient energy utilization. It is based on data obtained at Louisiana State University and elsewhere over the past few years.”

From Hillman, S., Culley, D.D. (1978) The Uses of Duckweed. American Scientist 66(4):442-451.

Figure 2. William S. Hillman and Dudley D. Culley, Jr., 1978

A duckweed/dairy farm

Emergence of the World-Wide Web in 1993-1994

Early Web Browsers, NCSA Mosaic and Netscape Navigator

In 1993 Mosaic was developed at the NSF-supported National Center for Supercomputing Applications (NCSA) at the University of Illinois, Urbana-Champaign. Mosaic was the world's first freely available Web browser that allowed Web pages to include both graphics and text.

Beginning in the early days of the web, it became customary for scientist-users to have their own web sites or home pages, filled with personal content. NSF encouraged Program Directors to use this space to create educational pages. So, while I was at NSF in 1994-1996, I began to learn the basics of web page design and HTML code.

1994 -1996 National Science Foundation

I began The Charms of Duckweed writing the web pages directly in HTML code.

1998 – 2001 Universities Space Research Association

The Charms of Duckweed first appeared in 1998 on the personal space provided by my Internet Service Provider (ISP). The website moved to the Universities Space Research Association in 1999. Since 2001, it has been hosted by the Missouri Botanical Garden.

Ventral view of Landoltia punctata showing conspicuous reddish underside and multiple (2-3) roots on each plant.

Wayne Armstrong

Palomar College

Botanical Consultant for the Palomar College Arboretum and editor of the Friend's of the Palomar College Arboretum Newsletter

Turions and mother fronds of Spirodela polyrrhiza

Cheryl C. Smart Fleming

University of Edinburgh,

Swiss Federal Institute of Technology

Ludmila V. Tsatsenko

Doctor of Biological Sciences, Professor

Department of Genetics, Breeding and Seed

Kuban State Agrarian University, Russia

http://www.kubagro.ru/chairs/genetic/staff.php

1. People and Events that led me to create The Charms of Duckweed

2. Helping me keep the website current and accurate

Two Themes:

Wayne P. Armstrong, Palomar College

Philomena Chu, Rutgers Univ.

Dudley D. (Bud) Culley, Louisiana State Univ.

Anne H. Datko, NIH/NIMH

Patrick Denny, IHE, Delft

Alberto Godoy, Panama City, Panama

Tim Journey, Aquasanitation

Louis Landesman, Virginia State Univ.

Elias Landolt , ETH

Luis Sala, Costa Brava Water Agency, Spain

Paul Skillikorn, Prism, Biotechnology Research and Development, LLC

Janet P. Slovin, USDA/ARS

Cheryl C. Smart Fleming , University of Edinburgh, ETH

Ludmila V. Tsatsenko, Kuban State Agrarian University

In summary, acknowledgment and appreciation go to these duckweed pioneers who have provided images content or other assistance to The Charms of Duckweed

People

Institutions The Missouri Botanical Garden Universities Space Research Association