story to find out more.
Sorghum root hair
with oily droplet exuding from tip. The exudate contains 80 to 90 percent
sorgoleone. Click the image for more information about it.
Exploring Sorghum's Knack for Keeping Weeds
Away By Luis
Pons May 9, 2005
Like people, most plants need their space. How much sunlight they get
and how large they grow are among the factors directly linked to how much room
plants have around them.
And when it comes to protecting its space, few plants are as assertive
That's why Agricultural Research
Service scientists who are seeking ways to keep weeds away from food crops
have taken a special interest in this drought-tolerant grain. Sorghum has been
gaining favor in the United States because of its natural cancer-fighting
compounds and digestibility by people with gluten intolerance.
Sorghum is one of many plants with allelopathic traits, according to
Duke, a plant physiologist in the ARS
Products Utilization Research Unit at Oxford, Miss.
The roots of allelopathic plants release plant toxins into the soil
that hold encroaching plants at bay.
Postdoc Daniel Cook uses gel electrophoresis of
DNA to clone genes involved in the biosynthesis of sorgoleone. Click the
image for more information about it.
Duke and his colleagues molecular biologists
Pan; plant physiologist
Dayan; and chemist
Rimando agree that sorghum's allelopathic properties are stronger
than those of most other plants.
Sorghum's main weapon is sorgoleone (sor-GO-lee-own), a compound
that's more active in fighting weeds than most other allelopathic compounds in
other plants. Sorghum produces sorgoleone at the root and the root hairs.
Researchers from the ARS unit are developing the basic information
needed to genetically increase the production of sorgoleone in sorghum,
according to Baerson. They're aided by a cDNA library they developed with help
from University of Georgia professor Lee
While this overall research may one day lead to introducing
allelopathic traits into other crops, care must be taken to ensure that
allelochemicals have no negative effects on nontarget organisms, including
people, according to Duke.
He says that it's unlikely that allelopathy can totally replace
herbicides in weed control. However, any naturally protective traits that could
even marginally reduce herbicide use would be financially and environmentally
more about this research in the May issue of Agricultural Research
ARS is the U.S. Department of
Agriculture's chief scientific research agency.