Using tissue culture to investigate plant cell differentiation and dedifferentiation

One of the challenges in teaching biology is designing laboratory exercises that introduce important concepts and techniques, provide some latitude for independent study, and which ore not prohibitively expensive. Described here is an experimental project that uses plant tissue culture techniques to examine cell differentiation in the carrot. The project permits students to gain experience in some important techniques, and to explore fundamental questions about cell differentiation and dedifferentiation. Students examined the influence of tissue type and tissue age on the ability of cells to alter their developmental fates and produce callus, a disorganized, dedifferentiated tissue. This project facilitated discussion about the differences and similarities in the permanence of developmental fetes of different plant tissues as well as animal tissues, and it led to the formulation of new and interesting, testable questions.