Содержание
- 2. History of Earth’s Climate Life appeared ~3.8 billion years ago Photosynthesis began 3.5-2.5 billion years ago
- 3. Earth’s Temperature The temperature of the earth is directly related to the energy input from the
- 4. Earth’s Temperature If amount of solar energy absorbed by the earth is equal to the amount
- 5. Earth’s Temperature if the amount of solar energy is greater than the amount radiated, then the
- 6. Earth’s Temperature If the amount of solar energy is less than the amount radiated, then the
- 7. Greenhouse Effect Sun To a certain degree, the earth acts like a greenhouse. Energy from the
- 8. Earth’s Atmospheric Gases Non- Greenhouse Gases 99% Greenhouse Gases 1%
- 11. Recap and importance: The photochemical reactions produce ATP and NADH at sites in the stroma. The
- 12. The Calvin cycle proceeds in three stages: carboxylation, reduction, and regeneration Carboxylation of the CO2 acceptor,
- 13. The affinity of Rubisco for CO2 is sufficiently high to ensure rapid carboxylation at the low
- 14. Basics of foliage photosynthesis Any questions? Increasing CO2 concentration in the atmosphere can increase the maximum
- 15. It is believed that photorespiration in plants has increased over geologic time due to increasing atmospheric
- 16. Decarboxylation of malate (CO2 release) creates a higher concentration of CO2 in bundle sheath cells than
- 17. Crassulacean Acid Metabolism (CAM) Uses C4 pathways, but segregates CO2 assimilation and Calvin cycle between day
- 18. Efficiency in light
- 19. ISOTOPES AND LAND PLANT ECOLOGY C3 vs. C4 vs. CAM
- 20. Cool season grass most trees and shrubs Warm season grass Arid adapted dicots Cerling et al.
- 21. εp = δa - δf = εt + (Ci/Ca)(εf-εt) When Ci ≈ Ca (low rate of
- 22. Ci, δi Inside leaf Ca,δa Ca,δa Cf,δf φ1,δ1,εt φ3,δ3,εt φ2,δ2,εf -12.4‰ -35‰ -27‰ Plant δ13C (if
- 23. Ci/Ca In C4, L is ~ 0.3, so εp is insensitive to Ci/Ca, typically with values
- 24. Δ13C fraction-whole plant
- 25. δ13C varies with environment within C3 plants C3 plants
- 26. Quantum Yield (moles C fixed per photons absorbed) Temperature (°C) 3 6 9 12 15 18
- 27. What happens when pCO2 changes? Ehleringer et al. 1997 Oecologia C3 decreases in efficiency because of
- 28. Quantum Yield (moles C fixed per photon absorbed) Temperature (°C) 3 6 9 12 15 18
- 29. C3 versus C4 plants C3 plants are favoured in environments where water is plentiful, temperature and
- 30. 9/12/07
- 31. 9/12/07 Three modes of photosynthesis C3 pathway, aka Calvin cycle, most common. Ribulose bisphosphate (RuBP, Rubisco)
- 32. 9/12/07 Calvin Cycle
- 33. 9/12/07 Photorespiration depends on light “wastes” CO2 protects against light damage favored by high O2, low
- 34. 9/12/07 Three modes of photosynthesis C4 pathway, aka Hatch-Slack, has additional enzyme, PEP carboxylase, with much
- 35. 9/12/07
- 36. 9/12/07 Three modes of photosynthesis C4 pathway Higher T optimum and light saturation. High water use
- 39. • There is a clear correlation between the amount of anthropogenic CO2 released to the atmosphere
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