BIOL208 Lecture Notes - Lecture 7: Photosynthetically Active Radiation, C3 Carbon Fixation, C4 Carbon Fixation
29 Feb 2016
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Document Summary
Autotroph- use inorganic sources of carbon and energy. Heterotrophs: use organic molecules as sources of carbon and energy. Par- photosynthetically active radiation measured as photon flux density (pfd). Each quantity of energy in light is what plants harness to get energy. Ir: too low in energy to facilitate photosynthesis. Uv: too high in energy to facilitate photosynthesis (break down cellular components, molecular mechanisms, etc). Visible spectrum: range at which photosynthesis can occur. (the middle wavelengths are not as useful as the extreme wavelengths from this region). About 45% of all light is useful for photosynthesis. We can measure photosynthetic light with a par* the higher the par, the more photosynthesis can occur. Microclimate variation also affects photosynthesis: example in water: light only penetrates a certain depth and this will depend on the solutes in water. Forests: light penetration in canopy is excellent, but as light penetrates the forest floor the light that reaches that area is not as great.
