Contact: Kara Villamil, or Mona S. Rowe

ISSUED 12/9/97



Leaf discovery important
for global climate change studies


UPTON, NY - A new study of leaves from 280 diverse plant species from all over North America shows striking similarities in structure and function, despite different evolutionary origins.

Far from just a curiosity, the finding could make it easier to use computers to model the Earth's vegetation and the effects of climate. Such models attempt to predict the effects of global climate change on the plants and trees that produce much of the world's oxygen, food and shelter, and absorb much of its airborne carbon dioxide.

The result is published in today's issue of the Proceedings of the National Academy of Sciences by scientists from the University of Minnesota and the U.S. Department of Energy's Brookhaven National Laboratory, led by Minnesota's Peter Reich.

"This research addresses an important question that has dogged ecologists and evolutionary biologists for two centuries: 'Do plant species around the world produce leaves with similar forms in different climates?'," said David Ellsworth, BNL tree physiologist. "We have found that the lifespan of leaves and their form and function show repeated patterns in ecosystems spanning nearly the entire range of climates worldwide."

"Of course, this doesn't mean that a tropical poinsettia is the same as an alpine fir tree," Ellsworth continued, "but our results offer great promise for global-scale modelers who desperately seek measuring tools that they can use when facing the difficult challenge of assessing how global climate change might affect plant function."

The authors' article describes their research on plants found in climate regions, or biomes, ranging from tropical and temperate forests to alpine tundra and desert.

Such biomes feature vastly different temperature ranges, precipitation levels, soils and species evolutionary histories. But the plants found in every one of the regions seem to share certain relationships between different factors like their nutrients and the amount of photosynthesis they performed, and the carbon dioxide they release through a process called respiration.

The relationships we describe will help scientists make quantum-leap simplifications in models and measurements without having to fully measure or understand every one of the thousands of plant species on earth," Ellsworth said.

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