A flexible, multi-week approach to plant biology - How will plants respond to higher levels of CO2?

Abstract

To help introductory biology students understand how plants will respond to higher levels of CO 2, we have created a multi-week module consisting of a series of four related laboratory lessons. These lessons allow students to make connections among morphological, physiological, and growth responses of Brassica rapa (Fast Plants®) to low (400 ppm) and high (800 ppm) concentrations of atmospheric carbon dioxide (CO 2). Elevated CO 2 was chosen as an environmentally relevant variable of high interest to our students as they consider the environment of their futures. However, this module is easily adaptable to test other plant species and/or variables ( e.g., light, nutrients, soil contaminants, genotypes, biotic factors, etc.), depending on instructor/student interests and available facilities/equipment. Within our modular framework, students analyze stomatal densities, photosynthetic and respiratory rates, foliar protein concentrations, and growth/allocation patterns. Progressive, weekly analysis of B. rapa responses to high and low CO 2 concentrations allows students to apply their findings and make predictions about plant responses in subsequent lessons. After all responses are measured, this framework facilitates student synthesis as they describe the interconnectedness of the measured processes and reflect on how these responses contribute to "how plants will respond to higher levels of CO 2."