PANNA: News Note: Estrogen-Like Compounds Affect Plants

A recent study in the journal Nature has shown that estrogen-like compounds in pesticides and other chemical pollutants can disrupt the chemical signaling process in plants. Although it is well documented that estrogen-like molecules interfere with animals' hormones, the study is the first to show that such molecules affect the signaling process in plants. The findings suggest that there could be a new range of potential affects on the environment and crops, as well as human and animal fertility.

Normally, leguminous plants such as soy bean, alfalfa, pea and clover send chemical signals to symbiotic bacteria in their roots. The plants use these bacteria to convert nitrogen in the air into a form used for manufacturing protein.

However, after assessing the effects of different chemicals on the bacteria's nitrogen fixing activity, the study found that certain chemicals -- such as the pesticide DDT -- disrupt the signals between the legumes and the bacteria in their roots. Researchers found that estrogen-like compounds caused up to a 90% decrease in the bacteria's nitrogen fixing activity.

By impairing nitrogen fixation, the application of certain pesticides may have the unintended effect of inhibiting plant growth. Widespread use of nitrogen-supplying fertilizers may have masked this effect, one researcher said.

The study raises concerns about the possible effects on humans and animals. When the signaling process between the bacteria and the plant breaks down and impedes nitrogen fixation, the nitrogen deficient plant increases its signal production. This could lead to elevated levels of natural phyto-estrogens in plants that could possibly be transferred in turn to the human or animal when consumed. Phyto-estrogens are known to mimic hormones -- especially those related to fertility -- in humans and other mammals.

Source: New Scientist, September 14, 2001.

Contact: PANNA.