Pyrolysis mass spectral characterization of wood from CAD-deficient pine

An extremely low level of the cinnamyl alcohol dehydrogenase (CAD) enzyme a ctivity in a mutant loblolly pine tree leads to a different pool of precurs ors for lignin production. Characterization of CAD-deficient wood by pyroly sis mass spectroscopy indicates significant increased levels of dihydro-con iferyl alcohol, not usually considered a lignin subunit. Also, in compariso n to normal pine lignin, the CAD-deficient lignin has increased levels of c oniferaldehyde, the substrate of CAD, and of p-coumaryl alcohol, along with greatly decreased levels of coniferyl alcohol. These findings are consiste nt with trees of different ages and confirm that there is considerable plas ticity in the biosynthesis of lignin. Trees are able to utilize structures beyond the traditional definition of precursors to make lignin.