Ecobreves – BRAZIL: Nitrogen in Soil Increases Carbon Absorption

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RIO DE JANEIRO, Feb 20 2012 (IPS) - The presence of nitrogen in soil speeds up plant growth, reducing the amount of carbohydrates in the leaves of plants and allowing them to live longer and absorb more carbon dioxide, a greenhouse gas, concludes a recent study by the Biosciences Institute at the University of São Paulo. "The lifespan of plants is divided between expansion, maturity and senescence (aging). The greatest production of carbohydrates takes place during the stage of maturity, and these lead to the senescence of the leaves," biologist Mauro Marabesi, who headed up the study, told Tierramérica.

The concentration of carbohydrates in the leaves results from their production in photosynthesis, minus the amount consumed through respiration and growth.

When there is nitrogen in the soil, plant growth and carbohydrate consumption is speeded up, so that fewer carbohydrates accumulate in the leaves, thus extending the stage of maturity and delaying the onset of senescence. "With more productive leaves, there is more photosynthesis and more carbon absorption," explained Marabesi.