Tracheary element differentiation

Differentiation of tracheary elements (TEs), characterized by formation of a visible secondary cell wall and autolysis, has been regarded as a model system for cytodifferentiation in plants. Fukuda and Komamine (Plant Physiol 65:57–60, 1980a) established an efficient experimental system for TE differentiation from isolated single mesophyll cells of Zinnia elegans. Physiological, cytological, and biochemical analyses of this system have revealed multiple aspects of TE differentiation regarding cell division, DNA synthesis, the cytoskeleton, autolysis, phytohormones, and cell wall components. In addition, molecular biological approaches have identified a number of Zinnia genes associated with TE-specific events. The knowledge obtained in the Zinnia system has been expanded to studies in other plants including Arabidopsis, leading to the identification of key regulators of TE differentiation.