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[14C]lignin-labeled lignocelluloses and 14C-labeled milled wood lignins: Preparation, characterization, and uses

1988; Academic Press; Linguagem: Inglês

10.1016/0076-6879(88)61005-6

1557-7988

Ronald L. Crawford, Don L. Crawford,

Horticultural and Viticultural Research

A convenient method for labeling the lignins of a variety of plants is to feed lignifying tissues 14C-labeled lignin precursors, such as L-phenylalanine, cinnamic acid, or ferulic acid. These precursors usually are incorporated preferentially into a plant's lignin, and with the proper workup procedures to remove low-molecular-weight 14C-labeled contaminants, one may prepare [14C]lignin-labeled lignocelluloses. Additional effort will yield 14C-labeled milled wood lignins. This chapter summarizes methods used to prepare, characterize, and use these two types of specifically 14C-labeled lignins. The most readily available precursor is L-[U-14C]phenylalanine, which can be purchased from numerous suppliers of radiolabeled compounds. This precursor will work well for many plants, especially rapidly lignifying hardwood species such as poplar (Populus sp.). However, some plants will incorporate too much L-phenylalanine into protein components of their tissues, and in these instances, precursors further along the lignin biosynthetic sequence are required. A typical procedure for administering labeled compounds to plants involves the use of plant cuttings.