Using Student-Produced Time-Lapse Plant Movies to communicate concepts in Plant Biology†

Objective To teach students a fun way to observe root growth and gravitropism by creating a time-lapse movie. Assign readings concerning seedling morphology, growth and gravitropism from the text or other sources; or have students find sources of information to use for class preparation. Curriculum Considerations Depending on your goals and resources, you can alter the exercise to study factors that affect root growth with a goal to have students develop hypotheses to test. This could also be used as a small class project. Materials 1. Clear plastic cups (2 for each setup). 2. Dark cotton fabric or brown paper towels cut into strips slightly smaller than the width of the cup. 3. Small seeds such as radish. 4. Props for stop-action practice session (e.g. Lego people or other lab materials that might make an interesting film). 5. Ruler to use for calibrating the images. Germination Procedure 1. Cut or punch 2 holes in the bottom of one cup. 2. Moisten the fabric with water and place it around the cup with the holes. 3. Holding the cup with the fabric on its side, place a couple of seeds on the fabric about 1 inch from the top. 4. Gently place the cup with the seeds into the other cup. Once the cups are nested the seeds should remain in place. 5. Add water to the center cup so that there is enough water to touch the bottom of the fabric. This will keep the seedling moist as it grows. 6. Allow the seeds to take up water overnight. Note: Radish seeds may germinate in less than one day. 7. Example images are provided in Figure 1. Camera SetUp Prepare an area for the computer with a webcam, tri-fold board background, and light source in a location than can remain undisturbed for a period of time. Depending on time and resource constraints you may opt to select 1-2 of the student's video designs (i.e., different capture timing or setup variations) to run for this part of the lab. Or, student teams could sign up for a time-slot for using the camera setup throughout the week. During the lab session, students can practice using the camera. Each team of students will take 5-10 shots using the props available at the camera setup. The shots from all teams will be compiled into a class stop-action movie. Fig. 1. A. Radish seedlings germinating …