In this three week lab, students use the technique of making clear nail polish impressions of leaf stomata to generate and test an hypothesis of their choice about how leaf stomata density might vary under different environmental conditions. First, students learn how stomata density affects leaf carbon, water, heat budgets, and photosynthesis. Then, students design their own study to compare stomata density among leaves that differ in biophysical environment on their campuses. Over the next two weeks, students collect and analyze their data (graphs and t-tests), and present their results in an in-class symposium.
MULTIWEEK - three 3 hour lab periods.
OUTSIDE OF CLASS TIME:
4-12 hours during which students collaborate to generate their written reports and prepare for their oral presentations.
Students are assessed based on their oral and written presentations, their written responses to background questions about plant stomata and other topics, on their written stomata research proposal, on their data collection and management skills, and on their participation in discussions in the stomata results symposium.
Outdoors on campus for data collection (any season - even mid-winter), back in lab for data analysis.
Undergraduate freshmen biology and other science majors (course name: Introduction to Organismal Biology - Bio 162), 12-16 per lab section.
Metropolitan private primarily undergraduate university.
It could be modified to run in any undergraduate introductory biology lab course (major or non-major) at any college or university. It also could run in introductory lab courses in botany, ecology, environmental science, or upper division courses in a variety of sub-disciplines. It could also be modified to run in biology lab courses in grades 8-12.
stomata impressions from a leaf
underside made using clear nail
polish viewed at 400x
© Marc Brodkin, 2000
full size image