Plants That Grow Fast May Have Advantage

WASHINGTON (AP) -- The ability to grow like a weed may be an advantage when it comes to coping with climate change. Plants with short life cycles can adapt more quickly to change than those that reproduce slowly, according to a new study by researchers at the University of California, Irvine. The findings are reported in Tuesday's issue of Proceedings of the National Academy of Sciences.

"Some species evolve fast enough to keep up with environmental change. Global warming may increase the pace of this change so that certain species may have difficulty keeping up. Plants with longer life cycles will have fewer generations over which to evolve,'' Arthur Weis, professor of ecology and evolutionary biology, said in a statement.

Weis and colleagues focused on Brassica rapa -- field mustard -- a plant classified as an annual because it goes from seed to flower and back to seed in one year. That allows for more rapid evolution than something like a redwood, which takes years to reach maturity and reproduce.

The researchers had collected seeds near the school campus in 1997, two years before a long drought set in. They also collected after the drought, in the winter of 2004.

Both groups of seeds were then planted at the same time in greenhouses.

The post-drought seeds flowered earlier than those collected before the drought, a shift in timing that would enable them to complete seed production before the soil dried out. Plants that bloomed later withered before they could set seed.

"Early winter rainfall did not change much during the drought, but the late winters and springs were unusually dry. This precipitation pattern put a selective pressure on plants to flower earlier,'' co-author Steven Franks said in a statement.

In a separate paper in the same issue, researchers report that amphibians such as salamanders and frogs appear able to adapt rapidly to changes in the environment.

Kim Roelants of Vrije University in Brussels, Belgium, and colleagues report that they found no major extinctions of amphibians in a study of the fossil record of periods when other land animals were undergoing major extinctions.

Instead, their analysis showed periods when amphibians diversified rapidly, an indication that they coped with change by changing themselves, rather than by dying out.

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