extracts salicylic acid from potato leaves and measures it with
high-performance liquid chromatography. Click the image for additional
information about it.
story to find out more.
Boosting Potatoes' Natural Ability to
Protect Themselves By
December 2, 2003
Potato and other plants have the means to defend themselves from
hungry insects and microbes that cause disease. But some plants don't mobilize
these defenses in time to do much good. Now, Agricultural Research Service scientists
are testing a way to snap such sluggish plants to attention and steel them for
In studies at Prosser, Wash., the scientists are spraying the
plants with salicylic acid, a substance familiar to many as an ingredient in
aspirin. In plants, it functions as a natural signaling compound that triggers
a protective response called "systemic acquired resistance," or SAR.
Plant scientists have known about SAR for years, but only
recently have SAR-activating products become available for use on crops
including tomatoes, lettuce and spinach. Healthier plants and reduced pesticide
use are among the benefits associated with activating SAR.
But according to Roy Navarre, a molecular biologist at the ARS
Vegetable and Forage Crops Research
Unit in Prosser, little is known about such benefits in potatoes, a crop
that generates nearly $3 billion annually in U.S. farmgate sales.
So, earlier this year, he and colleagues kicked off a project to
find out. Through lab and field studies, their objective is to determine which
SAR activators work best, in what parts of the potato plant, for how long, and
at what doses.
Scientists also test the activated plants' SAR defenses by
inoculating the plants with organisms such as late blight fungus, white mold,
potato virus Y, green peach aphid and Columbia root-knot nematode. Chemical
fumigants are a staple defense against the latter pest, but pumping them into
the soil can cost farmers $250 an acre.
Navarre is encouraged by the studies' early results, especially
against viruses, for which there is no direct method of control.
more about this research in this month's issue of Agricultural Research
ARS is the U.S. Department of
Agriculture's chief scientific research agency.