Rosenthal - Crop fertilization
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The document discusses the effects of elevated CO2 levels on crop fertilization, focusing particularly on cassava and its photosynthesis responses. While elevated CO2 increases cassava's photosynthesis and biomass, it also leads to downregulation of the Rubisco enzyme and does not meet theoretical predictions due to various factors such as ozone levels and plant respiration rates. The findings indicate that adaptation to rising CO2 levels is necessary for optimizing crop yields in a changing climate.
![Recent evidence indicates atmospheric [CO2] is
increasing more rapidly than the most aggressive
IPCC AR4 projection .](https://image.slidesharecdn.com/rosenthalforweb-110126165846-phpapp01/85/Rosenthal-Crop-fertilization-3-320.jpg)
![[CO2] (µmol mol-1)
750
96% of minute
averages within ±10%
550
Fumigation
350 On
0:00 6.00 12:00 18:00 0.00
Time (h)](https://image.slidesharecdn.com/rosenthalforweb-110126165846-phpapp01/85/Rosenthal-Crop-fertilization-12-320.jpg)
![Meta analysis of C3 crops grown at elevated CO2 in
FACE experiments
Crop Yield
Biomass
SLA
LAI
Plant Height
Leaf #
Starch
Sugar
Narea
Rubisco
Jmax
Vcmax
ci/ca
gs
A'
Asat
-40 -20 0 20 40 60 80 100 120
Percent Change in Elevated [CO2]
Ainsworth and Long (2005) New Phyt. 165:351=-372](https://image.slidesharecdn.com/rosenthalforweb-110126165846-phpapp01/85/Rosenthal-Crop-fertilization-14-320.jpg)
![Growth at elevated [CO2] at SoyFACE stimulates cassava
photosynthesis
Rosenthal et al. unpublished](https://image.slidesharecdn.com/rosenthalforweb-110126165846-phpapp01/85/Rosenthal-Crop-fertilization-18-320.jpg)
![Growth at elevated [CO2] does not increase leaf or
tuber cyanide content at SoyFACE
Miller, Gleadow unpublished](https://image.slidesharecdn.com/rosenthalforweb-110126165846-phpapp01/85/Rosenthal-Crop-fertilization-25-320.jpg)
![“[CO2] Fertilization” of C3 crop
photosynthesis falls short of theory
Long, Ainsworth, Leakey, Nosberger, Ort (2006) Science 312, 1918-21](https://image.slidesharecdn.com/rosenthalforweb-110126165846-phpapp01/85/Rosenthal-Crop-fertilization-26-320.jpg)
![Tobacco over-expressing SBPase grown at
elevated [CO2]
WT SBP 30 SBP 11](https://image.slidesharecdn.com/rosenthalforweb-110126165846-phpapp01/85/Rosenthal-Crop-fertilization-31-320.jpg)
![Over expression of SBPase enhances photosynthesis at
elevated [CO2]
Rosenthal et al. unpublished](https://image.slidesharecdn.com/rosenthalforweb-110126165846-phpapp01/85/Rosenthal-Crop-fertilization-32-320.jpg)
![Over expression of SBPase enhances biomass formation at
elevated [CO2]
Rosenthal et al. unpublished](https://image.slidesharecdn.com/rosenthalforweb-110126165846-phpapp01/85/Rosenthal-Crop-fertilization-33-320.jpg)
![Summary
• Growth at elevated [CO2] stimulated cassava
photosynthesis.
• Rubisco was down regulated in cassava at elevated [CO2],
consistent lower leaf N (no change in cyanide content).
• Fresh and dry tuber biomass significantly increased with
[CO2], as did harvest index.
• Cassava responded similarly to other C3 plants treated with
elevated [CO2].
• CO2 stimulation of photosynthesis is less than predicted by
theory.
- lack of adaptation to rapid increase in [CO2]
- inhibition due to increasing levels of tropospheric O3
- increased rates of respiration in CO2-grown plants
- temperatures above optimum for photosynthesis.](https://image.slidesharecdn.com/rosenthalforweb-110126165846-phpapp01/85/Rosenthal-Crop-fertilization-42-320.jpg)
Rosenthal - Crop fertilization
- 1. Crop Fertilization in a CO2 enriched world: is it good to be C3 David M. Rosenthal CCAFS Science Workshop, Cancun, Dec 1 and 2, 2010
- 2. Outline • Plant responses to elevated CO2 and other agents of climate change at SoyFACE • Why is photosynthesis of crop plants in the field stimulated less by CO2 than predicted by theory? • Some approaches to optimize (adapt) photosynthesis to global change
- 3. Recent evidence indicates atmospheric [CO2] is increasing more rapidly than the most aggressive IPCC AR4 projection .
- 4. How does elevated CO2 stimulate photosynthesis that is the basis for the projected increases in yield?
- 5. Rubisco is not the most efficient enzyme
- 6. Energy conversion in C3 and C4 plants Zhu et al 2008
- 7. SoyFACE Experiment Maize Soybean
- 8. 20 meters
- 12. [CO2] (µmol mol-1) 750 96% of minute averages within ±10% 550 Fumigation 350 On 0:00 6.00 12:00 18:00 0.00 Time (h)
- 13. Increased photosynthesis in C3 crops grown at elevated CO2 increases yield Long, Ainsworth, Leakey, Nosberger, Ort (2006) Science 312, 1918-21
- 14. Meta analysis of C3 crops grown at elevated CO2 in FACE experiments Crop Yield Biomass SLA LAI Plant Height Leaf # Starch Sugar Narea Rubisco Jmax Vcmax ci/ca gs A' Asat -40 -20 0 20 40 60 80 100 120 Percent Change in Elevated [CO2] Ainsworth and Long (2005) New Phyt. 165:351=-372
- 15. No CO2 stimulation in Cassava Greehouse Experiment Gleadow et al. (2009) Plant Biol 11:79-82
- 16. Cassava an increasingly important crop
- 17. CassavaFACE cv 60444 April 5, 2010 June 7, 2010 August 9, 2010 April 15, 2010 July 2, 2010 July 19, 2010
- 18. Growth at elevated [CO2] at SoyFACE stimulates cassava photosynthesis Rosenthal et al. unpublished
- 19. Cassava canopies are larger at elevated CO2 plant Ambient CO2 Elevated CO2 Rosenthal et al. unpublished
- 20. Rosenthal et al. unpublished
- 21. Cassava harvested after only 3.5 months ! Elevated Ambient
- 22. Ambient CO2 Elevated CO2 Rosenthal et al. unpublished
- 23. Rubisco is down regulated at elevated CO2 in cassava
- 24. Cassava leaf Carbon/Nitrogen ratio declines at elevated CO2 Rosenthal et al. unpublished
- 25. Growth at elevated [CO2] does not increase leaf or tuber cyanide content at SoyFACE Miller, Gleadow unpublished
- 26. “[CO2] Fertilization” of C3 crop photosynthesis falls short of theory Long, Ainsworth, Leakey, Nosberger, Ort (2006) Science 312, 1918-21
- 27. Why is photosynthesis of crop plants in the field stimulated less by CO2 than predicted by theory?
- 28. 400 Current value 320 240 160 Years below 280 ppm, 395 000 (96%) 80 Years below 240 ppm, 280 000 (67%) Years below 200 ppm, 83 500 (20%) 0 400 320 240 160 80 0 Time before present, 103 years Various sources ; Luthi et al (2008) NATURE 453: 379-382
- 30. Zhu et al. (2007) Plant Physiol 145: 513-526
- 31. Tobacco over-expressing SBPase grown at elevated [CO2] WT SBP 30 SBP 11
- 32. Over expression of SBPase enhances photosynthesis at elevated [CO2] Rosenthal et al. unpublished
- 33. Over expression of SBPase enhances biomass formation at elevated [CO2] Rosenthal et al. unpublished
- 34. PGA PGA CH2OPO32- CH2OPO32- HO C H CH2OPO32- HO C H O2 CO2 COO- C O COO- H C OH COO- H C OH COO- CH2OPO32- CH2OPO32- HO C H Ribulose-1,5- CH2OPO32- 2-phospho- bisphosphate glycolate PGA
- 35. Non-green algae C4 Terrestrial C3 Mutants Prokaryotes
- 36. There is a trade off between ability of Rubisco to discriminate between CO2 and O2 Rubisco catalytic rate Increase ? Decrease ? Current C3 crop Rubisco
- 37. Lowering increases light saturated leaf photosynthesis but lowers light limited photosynthesis = -10%
- 38. C3 Average
- 39. Adding „foreign‟ Rubisco Species Ac' = CANOPY εc Asat PHOTOSYNTH. (% inc.) ( mol m-2 s-1) (mmol m-2 day-1) Current average C3 crop (kcc = 2.5, = 92.5) 1040 0% 14.9 Amaranthus edulis (C4) (kcc = 7.3, = 82) 1250 17% 28.3 Amaranthus edulis/current (kcc = 7.3/2.5, = 82/92.5) 1360 31% 28.3 (2004) Plant Cell and Environment, 27, 155-165
- 40. Rising tropospheric ozone 0.5 – 2.5 % per year Ozone – Parts Per Billion of Air 80 60 40 2000 2020 2040 2060 2080 2100 (UN-IPCC 2001)
- 41. Relationship between Soybean Yield & Ozone Fishman et al.2010 Atmospheric Environment
- 42. Summary • Growth at elevated [CO2] stimulated cassava photosynthesis. • Rubisco was down regulated in cassava at elevated [CO2], consistent lower leaf N (no change in cyanide content). • Fresh and dry tuber biomass significantly increased with [CO2], as did harvest index. • Cassava responded similarly to other C3 plants treated with elevated [CO2]. • CO2 stimulation of photosynthesis is less than predicted by theory. - lack of adaptation to rapid increase in [CO2] - inhibition due to increasing levels of tropospheric O3 - increased rates of respiration in CO2-grown plants - temperatures above optimum for photosynthesis.
- 43. CassavaFACE collaborators: Becky Slattery (UIUC) Kat Grennan (UIUC) Bec Miller (Monash U) Ros Gleadow (Monash U) Claude Fauquet (ILTAB) SBPase overexpression collaborators Christine Raines (U Exeter) Anna Locke (UIUC) Stephen Long (UIUC) SoyFACE 2010