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14 Cards in this Set
- Front
- Back
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The cosine law
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light incident on a leaf varies with leaf angle and canopy position. Incidence (I) = COStheta
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diaheliotropism
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heliotrophic leaf movement following the sun to maximize absorption
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paraheliotropism
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pleaf movement to minimize absorption by moving parallel to the sun
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PAR - photosynthetically active radiation
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density of photons between 400-700 nm. aka. incident light
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3 causes for differences in in PAR at forest floor
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1.species - leaf properties
2. Density -LAI, LAD etc. 3. Architecture - leaf distr. |
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photomorphogenesis
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light mediated plant development.
ex. light vs dark germination, phytochrome |
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LAI - leaf area index
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leaf area per unit ground area. affects penetration of light through canopy and quality of light
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Quantitative absorption
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Qf = Qte^-kx where
Qf = flux density Qt = total or top of canopy irradiance K = extinction coefficient for particular species x =LAI-optical mass of canopy e = 2.718 (ln) |
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erectophile vs planophile canopy
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vertical vs horizontal leaf hang
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Sunflecks
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areas when sunlight reaches forest floor uninterrupted
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sun vs shade anatomy
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thick leaf, strong insolation by mesophyl, transcurrent vascular bundles vs. thin leaf, weakly developed vascular bundles, loose spongy parenchyma. genetic and environmental basis.
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sun vs shade biochemestry
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results in differences in light compensation point, quantum efficiency, respiration rate etc.
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photoinhibition
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light INDUCED reduction of photosynthetic capacity
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phytochrome
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protien of 2 polypeptides attached with a chromophore(pigment receptor). changes isomers between red and far red exposure
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