Measurement of Nitrogen Fixation using H2 Sensor

Measurement of Photosynthesis using O2 Sensor

Measurement of Plant Respiration using O2 Sensor

Measurement of Insect Respiration using CO2 Analyzer

Measurement of Photosynthesis using CO2 Analyzer

Support and Funding

National Science Foundation

The views expressed by the author are not necessarily those of the National Science Foundation

Andrew W. Mellon Foundation

Laboratories for Measuring Physiological Processes in Plants and Animals

The laboratory materials found on the following pages were developed with funding from the National Science Foundation in the form of an Instrumentation and Laboratory Improvement (ILI) grant and with support from the Mellon Foundation and Grinnell College. The goal of this project was to enable students to conduct experiments on the physiology of plants (and animals) using computer-based instrumentation that allows them to acquire and display data in real time. These materials are designed to introduce students to the equipment and to provide experiments that will illustrate the types of studies that one can conduct. They should also serve as the starting point for student-designed investigations.

The web site is organized into five different types of investigations, each built around physiology equipment purchased from Qubit Systems, Inc., Ontario, Canada. These are:

  1. Nitrogen fixation measurements using a H2 sensor
  2. Photosynthesis measurements using an O2 sensor
  3. Plant respiration measurements using an O2 sensor
  4. Insect respiration measurements using an infra-red gas analyzer (IRGA)
  5. Photosynthesis and respiration measurements using an IRGA

Laboratory exercises were developed for a multi-section introductory biology course called "Structure and Function of Organisms" as well as for an advanced plant physiology course. They have been used in both of these courses as well as two new courses; "Introduction to Biological Inquiry" (introductory level) and "Molecules, Cells & Organisms" (sophomore level)..

Each section of the web page contains an introduction to one of the three instrumentation systems and its set-up and, in the case of the gas flow systems, is accompanied by an interactive prelab to test the students' understanding of the correct way to connect the system for different parts of the experiment. This is followed by the text of the laboratories developed for that particular system.

If you have any questions regarding these materials or would like to talk with me about their use in the laboratory, please feel free to contact me at:

Diane C. Robertson
Biology Department
Grinnell College
Grinnell, Iowa 50112

641-269-3039 (office)
641-269-4285 (fax)
robertdc@grinnell.edu