Plant tissue cultures are an efficient system to study cell wall biosynthesis in living cells in vivo. Tissue cultures also provide cells and culture medium where enzymes and cell wall polymers can easily be separated for further studies. Tissue cultures with tracheary element differentiation or extracellular lignin formation have provided useful information related to several aspects of xylem and lignin formation. In this chapter, methods for nutrient medium preparation, callus culture initiation, and its maintenance, as well as those for protoplast isolation and viability observation, are described. As a case study, we describe the establishment of a xylogenic culture of Zinnia elegans mesophyll cells.