4+NutrientCycles_EcolOfPhotosynt

co2 efciency of photosynthesis predicted c3 diff

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Unformatted text preview: ts efficiency of C3 & C4 as a function of temp. & [CO2] efficiency of photosynthesis predicted C3, diff. [CO2]’s observed C3, 350 ppmV observed C4, 350 ppmV now add competition temperature (C) Ehleringer et al. 1997. Oecologia 112, 285-299 C3 & C4 photosynthesis as a function of temp. & [CO2] can explain seasonal & latitudinal variation in abundance of C3 & C4 grasses atmospheric [CO2] outcome of competition depends on temp. & [CO2] daytime growth season temp (C) Ehleringer et al. 1997. Oecologia 112, 285-299 C3 & C4 photosynthesis as a function of temp. & [CO2] outcome of competition depends on temp. & [CO2] can explain seasonal & latitudinal variation in abundance of C3 & C4 grasses 0-30% C4 30-60% C4 60-100% C4 ex: latitudinal variation What expect for seasonal variation? Ehleringer et al. 1997. Oecologia 112, 285-299 Plant responses to elevated [CO2] Increased photosynthesis, increased plant growth “ecological cascade” consequences: stomata can close sooner/stay closed longer: less evapotranspiration, less water use higher soil moisture (ecosystem effect) decreased nutrient uptake from soil (bc less water uptake) changes in chemical composition of plant tissues: more carbohydrates (sugars, starches), less protein lower quality food for herbivores: eat more to compensate could affect human health? Harshaw Experimental Forest, WI Plant responses to elevated [CO2] outcome of competition depends on: photosynthetic pathway, temp., nutrient availability C4 legumes C3 rel. unresponsive to elevated [CO2] increased growth if nutrients available high nutrient conditions % C4 plants decreases (outcompeted by C3, which benefit from increased CO2) increased growth (symbiosis w. N-fixing bacteria) low nutrient conditions % legumes increases predicted change in composition of plant communities...
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This document was uploaded on 03/17/2014 for the course BIO SCI 310 at Wisconsin Milwaukee.

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