Projects and Laboratory Exercises This is a collection of ideas and links to sites with suggested experiments.  Some of the links provide complete packages of materials, including protocols, data sheets and report formats.  Others are more sketches of projects or suggestions.  Many of them involve counting fronds to measure population growth, but many other biological or chemical parameters can easily be investigated using these plants.  Two examples are plant dormancy and the growth and function of roots.  Right:  Spirodela collected from a wetland.

• See inside the plant:  A simple method of clearing and staining duckweeds will allow students to visualize the hidden structures of the frond using a magnifier or microscope. [ sample photo ]

• Exercises from  Science and Plants in Schools
  

Doubling and dabbling in duckweed. by Stephen Tomkins. In Osmosis, the SAPS Newsletter, Homerton College, Cambridge, UK.

Bioassays with duckweed by Stephen Tomkins. In Osmosis, the SAPS Newsletter, Homerton College, Cambridge, UK.

Student Sheet 21 - Measuring Duckweed (Lemna minor) with student and teacher notes.  Roger Delpech, Haberdasher's Askes' School

Experimental method and biological concepts demonstrated using duckweed. by G. Robinson (1988) School Science Review, 69(248), 505-508 Association for Science Education, College Lane, Hatfield, Herts AL10 9AA UK.  Download PDF File (143KB)


Assaying peroxidase activity in plant tissues.   Roger Delpech, Haberdasher's Askes' School.  This article provides a rapid technique for extracting and making quantitative measurements of peroxidase enzyme activity.  Duckweed tissues are suitable for this study.

• Environmental Inquiry (EI), is a website and curriculum series developed at Cornell University to help students conduct authentic environmental science research and participate in communities of fellow student scientists.  In 2003, EI won an Environmental Quality Award from EPA for Excellence in Environmental Education.  EI is dedicated to the creation, evaluation, and distribution of inquiry-based environmental science materials.  EI includes several topic areas, including environmental toxicology -- using bioassays to assess environmental health and making judgments about acceptable levels of risk  Each module includes activities to engage students in three progressive levels of inquiry, modeled after research activities that scientists normally conduct.  One of the labs is a phytotoxicity bioassay using duckweed.

• Exercises from a book published by the National Academy of  Sciences:

• An Inquiry-Based Laboratory Exercise: Ecology of  Duckweed, and (for comparison)
• A Traditional Laboratory Exercise: The Effect of pH on the Growth of Duckweed. 

Reference:  The Committee on Biology Teacher Staff, The Role of Scientists in the Professional Development of Science Teachers. National Academy Press, Hardcover - 175 pages (pub. May 1996).  Available from Amazon.com:  [ More information on this book ]

• "Population Dynamics of Duckweed," an activity from Access Excellence Activities Exchange by Truman Holtzclaw, Sacramento High School, Sacramento, CA

• "How Does Fertilizer Affect Aqueous Plants?" from the KDE (Kids Do Ecology) project, National Center for Ecological Analysis and Synthesis, Santa Barbara, CA. "Students will explore the pros and cons of fertilizer, and draw conclusions regarding the effects of increased vegetation in aquatic systems. [ no longer on-line]
  


A student write-up from this project, "How Pollution Affects Duckweed" by Mrs. Rogers-O'Reilly's 5th Grade Class, Adams Elementary School, Santa Barbara, CA, Spring 1998.  "We did an experiment to find out how pollution affects duckweed. We tested three types of pollution:  vinegar to mimic acid rain, lots of fertilizer to mimic a common urban pollution  and we also used golf course runoff from a golf course near our school to find out what it did to the local water, plants, and duckweed."

 
• A Science Fair Project, Does Lemna Minor Lower the Nitrate Level of Water? by Liza Zappaterreno, Divine Savior Holy Angels High School, Milwaukee, Wisconsin.  This project won a scholarship award in the 45th Annual Southeastern Wisconsin Science and Engineering Fair, March 27, 1999.  [ no longer on-line]
 
• View the results of an actual Lemna growth experiment by John W. Cross.  Note that there are no treatments shown in this experiment.  The cultures were replicated controls for treatments that are not presented here.  The purpose is to illustrate the variability of the data and how such growth data can be analyzed.

• Easy experiments on the function of duckweed roots.

• Study dormancy using Duckweed Turions, a dormant vegetative stage.

• How to clone duckweed.  Also, what are clones and why are they important?

• Does extra carbon dioxide (CO₂) stimulate duckweed growth?  Study how plants will respond to a changing environment.
       References:
       Assessing the impact of elevated CO2 on plants and ecosystems, from the Smithsonian Environmental Research Center.
       CO₂ and light stimulate the growth, by Ole Pedersen, Claus Christensen and Troels Andersen

• Biochemical and physiological research in duckweeds:  Links to a sample of current research available on-line.

• Books on duckweeds and other aquatic plants.
  

Please contact me if you know of other  learning experiments for schools or colleges.  If you have done a project and would like to put it on these pages as an example, I would be very interested.  I can help you format it and you will get credit for authorship.  Projects with data tables, drawings or photos are particularly desirable.
 
 
 
 

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Last revised:  December 17, 2011