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In this Experiment, students make impressions of leaf stomata (using clear nail polish) and test a hypothesis of their choice about how leaf stomata density might vary under different environmental conditions. Leaf stomata are the principal means of gas exchange in vascular plants. Stomata are small pores, typically on the undersides of leaves, that are opened or closed under the control of a pair of banana-shaped cells called guard cells. When open, stomata allow CO2 to enter the leaf for synthesis of glucose, and also allow for water, H2O, and free oxygen, O2, to escape. In addition to opening and closing the stomata (stomata behavior), plants may exert control over their gas exchange rates by varying stomata density in new leaves when they are produced (such as in the spring or summer). The more stomata per unit area (stomata density) the more CO2 can be taken up, and the more water can be released. Thus, higher stomata density can greatly amplify the potential for behavioral control over water loss rate and CO2 uptake.
Associated files
Resource Group TIEE
Resource Group Link
Primary or BEN resource type
Discipline Specific Core Concepts
Life science discipline (subject)
Keywords stomata; plant; leaf; photosynthesis; variation; environment; hypothesis; experiment; water; carbon dioxide; TIEE; pedagogy
Intended End User Role
Educational Language
Pedagogical Use Category
Pedagogical Use Description This Experiment can be used to teach about some of the mechanisms vascular plant species use to adapt to life in different environments. The activity provides background information on how stomata density affects leaf carbon, water, heat budgets, and photosynthesis. It guides students through the design of their own study to compare stomata density among leaves that differ in biophysical environment on their campuses. Then over two weeks, students collect and analyze their data (graphs and t-tests) and present their results in an in-class symposium.
Aggregation Level
Full Name of Primary Author Bruce Grant
Primary Author Controlled Name
Primary Author Affiliation Widener University, Dept. of Biology
Primary Author email
Added By Id
  • educationintern
Rights Copyright 2005 by Bruce W. Grant, Itzick Vatnick, and the Ecological Society of America.
Review type
Drought and Water Ecosystem Services Collection Off
Conservation Targets Under Global Change Collection Off
Big Data Collection Off
Editors Choice No
Resource Status
Date Of Record Submission 2007-11-05
I Agree to EcoEdDL's Copyright Policy & Terms of Use No
Date Of Record Release 2010-02-16 01:28:08
Last Modified By Id
  • educationintern
Date Last Modified 2018-07-18 11:07:46
Release Flag Published

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