A rapid staining method for the detection of suberin lamellae in the root endodermis and exodermis

Histochemical detection of suberin lamellae has remarkably advanced our understanding of the roles of the apoplastic diffusion barrier in the root endodermis and the oxygen diffusion barrier in the root exodermis. Fluorol yellow 088 detects the aliphatic component of suberin and is one of the most reliable stains for detecting suberin lamellae in the endodermis and exodermis. Although fluorol yellow 088 staining can detect suberin lamellae in various plant roots by a simple procedure, conventional methods are time-consuming, as they need a long time to prepare the solution, stain, and wash the samples. Here, we propose a rapid method to minimize the time required to achieve suberin staining using root cross-sections. While conventional methods use polyethylene glycol-glycerol or lactic acid as the solvent, we found that fluorol yellow 088 readily dissolves into ethanol. This modification remarkably shortened the time required to prepare the solution, stain, and wash root cross-sections. Thus, our method will enhance the study of root anatomy and the histological development of plant roots.