With Just a
Sprinkle, Plants Soak Up More Selenium
By Erin Peabody
February 24, 2004
Because of their ability to sop up
selenium, some plants have been enlisted in efforts to clean up soils and
wastewater that have an excess of this potentially toxic element. Now
Agricultural Research Service scientists
have shown that the way contaminated irrigation water is delivered to plants
affects how much selenium they will absorb from it.
Soil scientist Donald L. Suarez and plant physiologist Catherine M. Grieve,
working with soil scientist James A. Poss, found that sprinkling--rather than
flooding--kale and turnip plants with selenium-laden drainage waters allowed
the plants to absorb almost twice as much selenium from the water. Suarez,
Grieve and Poss are at the agency's George E. Brown Jr. Salinity
Laboratory in Riverside, Calif.
Boosting plants' uptake of selenium creates a place to naturally
"store" the element, thereby decreasing the amount of selenium that
might otherwise leach into drainage and groundwater.
As a possible additional benefit, the selenium-enriched kale and turnip
plants--as well as other crops irrigated by sprinkling--could be used to
supplement the diets of livestock raised in selenium-deficient regions of the
United States. Animals must consume some of this essential nutrient for optimum
growth and stress tolerance.
Suarez expects the sprinkler method to work with other crops, so the
findings are likely to aid growers who are interested in producing
selenium-rich vegetables for health-conscious consumers.
Sprinkling water onto the crops takes advantage of plants' ability to absorb
droplets of water through openings in their leaves. Plants can also soak up
selenium from water via their roots. But because plant roots screen out some
elements, leaf uptake can be a more effective way to capture the selenium.
ARS is USDA's chief in-house scientific