How Plants Make Lignin Researchers Begin to Count the WaysBy
Lignin is a must for plants--it provides their structure and
rigidity--but a headache for humans. For example, dairy producers
don't like lignin because it reduces the digestibility of forages, the
mainstay of U.S. dairy cow diets. And the paper industry spends
millions of dollars annually on lignin removal and clean-up costs.
Agricultural Research Service
scientists in Madison, Wis., say the next decade may bring relief in
the form of a new kind of lignin--one that's easier for dairy cows to
digest or for paper companies to extract.
John Ralph and Ron Hatfield of ARS'
U.S. Dairy Forage Research Center
in Madison are using a diagnostic analytical technology called nuclear
magnetic resonance (NMR) to study a natural mutant pine tree
discovered by North Carolina State researchers. The mutant tree is
missing one of the enzymes thought necessary for lignin production.
The absent enzyme--known as CAD--produces coniferyl alcohol, the main
building block for making lignin in normal pine trees. Even though the
mutant tree lacks this enzyme, it still produces lignin using two
other simple compounds in a way researchers have never before
Thanks to the NMR technology, the ARS scientists have provided the
first detailed description of the structure of this unusual lignin.
They are now looking for traits in lignins to make them easier for the
paper industry to pulp or for better digestibility in ruminant
animals. This information will allow plant molecular geneticists to
develop new plants with lignin that can be modified to suit specific
Scientific contact: John Ralph or Ron Hatfield,
U.S. Dairy Forage Research Center,
Agricultural Research Service, USDA, Madison, WI 53706-1108. Phone
(608) 264-5407 or (608) 264-5358, fax (608) 264-5147,