What Happens:

      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.

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Lab Objectives:

At the conclusion of this multiweek lab, students will:

1. students will have a basic understanding of structure and function of leaf stomata as well as the role of stomata in regulating gas and heat exchange in vascular plants,


2. Students will have actually done science - they will have generated a testable hypotheses, collected data, analyzed data, tested their hypothesis, and they will have reported their research results to their peers.

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Equipment/ Logistics Required:

* live plant material (of your choice),
* clear nail polish and clear plastic package tape,
* clean slides, marking pen, scissors, plastic slide holder,
* microscope and stage micrometer,
* computers with spreadsheet, presentation, and basic statistical software.

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Summary of What is Due:

      From this multiweek lab, students submit

• a one page co-authored research proposal composed according to the guidelines below (due at the end of the first lab),


• answers to any four of the questions for further thought contained in this handout (due in lab on the second week - students work alone on these),


• clearly labeled copies of students' original data including the actual slides taped to a plastic slide holder (due in class at the end of the second lab),


• co-authored stomata results report composed according to the guidelines below and presented in class (due at the beginning of the third lab), and


• a critical review of the lab activity (due one week after the third lab - students work alone).

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Keyword Descriptors:

Principal Ecological Question Addressed:     Effects of biophysical environmental conditions on the adaptive design of plant leaves.

Ecological Topic Keywords:     plant physiological ecology, biophysical ecology, environmental adaptation, stomata, photosynthesis, autecology.

Science Methodological Skills Developed:     field work, hypothesis generation and testing, microscopy, statistics, graphics, data analysis, scientific writing, oral research presentations.

Pedagogical Methods Used:     student-directed inquiry, cooperative learning, problem-based learning, scoring rubrics