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Article: Trees avoid Goldilocks' troubles: leaves sweat, huddle to keep temperatures favorable.(Earth)(Brief article)
- Article from:
- Science News
- Article date:
- July 5, 2008
- Author:
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Tree leaves achieve temperatures just right for photosynthesis, even in environments that are too hot or too cold.
From roughly the top to the bottom of North America, across some 50 degrees of latitude, trees do their photosynthesizing at leaf temperatures around 21.4 o Celsius plus or minus 2.2 degrees, says physiological ecologist Brent Helliker of the University of Pennsylvania in Philadelphia.
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He and colleague Suzanna Richter surveyed the ratios of two forms of oxygen that vary depending on leaf temperature and humidity. The ratios, which are transferred into the cellulose of tree rings, suggest that leaves maintained moderate ...