Lignin-carbohydrate complex formed in isolated cell walls of callus

Cell walls of Pinus elliottii tissue cultures were isolated and incubated with coniferyl alcohol and H₂O₂. Lignin having physical and chemical properties similar to that prepared from wood was formed by the peroxidase attached to the walls. Fractions of the callus lignin isolated enzymatically or chemically contained bound carbohydrate. The lignin was also strongly bound to a protein containing hydroxyproline, probably extensin. This system may be analogous to the earliest stage of normal lignin formation in which monomers are transported from the protoplast into the primary wall and middle lamella, where peroxidase polymerizes monomers and catalyzes bonds to carbohydrate and protein.