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Errors in how scientists account for water loss from leaves may be skewing estimates of how much energy plants make through photosynthesis, according to the latest research. This in turn could jeopardize models of how individual leaves function and even of the global climate. The errors are particularly pronounced when a plant’s water supply is limited — a condition of increasing interest as plant breeders and climate scientists grapple with the effects of global warming.
“If you’re trying to understand why a crop you’re growing or a particular plant is able to survive and do better under drier conditions, you may misinterpret that,” says plant physiologist David Hanson of the University of New Mexico in Albuquerque. Hanson presented his findings at the annual meeting of the American Society of Plant Biologists in Honolulu, Hawaii, on 25 June.
Researchers have long assumed that the main way that plants lose water is through leaf pores called stomata. When water is abundant, the stomata open wide to let carbon dioxide flow in — maximizing photosynthesis, but allowing water to exit. Plants also lose moisture through a leaf’s waxy outer surface, or cuticle, but this effect has been considered negligible