Chemical components, physiological functions and regulation mechanism of plant Casparian strips

Casparian strips are diagnostically modified structure mainly appeared in the endodermis, in which the radial parts of the cell walls are characterized by the deposition of lignin and suberin in the primary cell wall. As a barrier to the apoplastic movement of solutes from the cortex to the stele, Casparian strips are essential for the exclusion of salts and pathogens, selective nutrient uptake, and many other processes. With the development of biochemical analysis techniques and genetic research methods, the research in Casparian strips was increasing and has accumulated a large number of data. In this paper, we summarize the research progress in cytological structure, development processes, chemical components of Casparian strips. We focus in particular on recent advances in physiological functions and the regulation mechanism of Casparian strips during developmental processes and the response to different environmental conditions. This review can provide significant information for further investigation on the development of Casparian strips.