OVERCOMING HEAVY METALS

Up to 12 percent of soils under cultivation around the world contain metals that stunt plant growth and development and result in poor harvests.

In the past, plant breeders dealt with this problem by crossing metal-sensitive plant varieties with species that thrive in this type of poor soil. NSF-funded researchers are using genetic engineering to improve plant traits, ranging from pest resistance to nutritional value, from developing plants that flourish on metal-rich soils, to helping other plants clean up heavy-metal contamination.

NSF-funded researchers at Cornell University are studying aluminum toxicity and tolerance levels in plants, since aluminum levels in plants are a major factor limiting crop productivity.This research has shown that aluminum starts a process through which certain acids are discharged into the soil. These acids in the soil protect the roots from the harmful effects of the aluminum.

Improving food production
A better understanding of the mechanisms involved in this process will have important implications for agricultural food production.

Understanding plant iron uptake is highly important because one-third of the world's soils are iron deficient. Iron deficiency in humans is the most prevalent nutritional problem in the world today, affecting an estimated 2.7 billion people in industrial and developing countries.

Plants and nutrition
Plants are the major source of iron for most of the world;ensuring that plants have higher amounts of iron would help in solving an important human nutritional problem.

In the future, crops could be manipulated to become several times richer in iron, or to become so efficient at extracting iron from the ground that they could grow in soils that would not normally support them.

Research may also lead to the discovery of genes responsible for uptake or absorption of other metals, such as copper, by plants. Manipulating these genes could lead to phytoremediation, a method of removing pollutants from industrial wasteland by growing plants on it. This process may become more efficient if plants become able to absorb greater quantities of metals from the ground.