This document discusses tracer techniques used to study biosynthetic pathways in plants. It begins with an introduction to different biosynthetic pathways and techniques used to study them, including tracer techniques. Tracer techniques involve using labeled compounds, such as radioactive isotopes, to trace intermediates and steps in biosynthetic pathways. The document then discusses specific tracer techniques in detail, requirements for tracer techniques, advantages and limitations, and applications for studying various plant secondary metabolites and biosynthetic pathways.