BIO120H1 Chapter Notes -Stoma, Volumetric Heat Capacity, Sonoran Desert
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BIO120H1 Full Course Notes
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Document Summary
Plant physiological ecology as a tangle of constraints and tradeoffs. The same principles and tradeoffs in lecture 3 apply to plants as well: Sa/v considered important as heat balance and water balance are needed. Most terrestrial plants photosynthesize in leaves and thus leaves need to offer large surface areas for sunlight exposure. This large surface area in leaves also needed for gas exchange. Problem=large sa in sunlight puts tissues at risk to point where enzymes in leaf denature. Stomata=little openings at bottom of leaf where gas exchange takes places. However, water from leaf interior evaporates thru stomata. Biochemical specializations of photosynthetic pathways, specifically the way that co2 capture or carbon fixation takes places. In temperate climates, plants do this by c2 pathway (named b/c co2 first goes into a 3 carbon compound. This is not efficient in water use and also captures oxygen, which causes wasteful photorespiration at high temps. C4 found in maize and sugar and is independent.
