1. The productivity of plants is effected before visible damage Ground Level Ozone Workshop Saturday March 7, 2009 Stony Brook University No visible symptomsModerate damageSevere damage Alistair Rogers Vandermeiren et al (2005)

3. New York State NO x emissions (tons mile -2 ) 0 – 5 5 – 10 10 - 2000 www.airnow.gov

4. 0 - 64 65 - 84 85 - 104 105 - 124 125+ Ozone concentration

5. Ozone concentration has risen by 36% since the industrial revolution and is predicted to increase at a rate of 0.5 to 2.5% per annum IPCC (2001, 2007) Ozone (ppb) Year

6. Seasonal average of daily peak ozone (ppb) 04080120 Percent yield no ozone 40 60 80 100 Soybean Wheat Sorghum Corn (USDA) Mean crop responses to ozone

7. Feng & Kobayashi (2009) Current impact of background ozone on crop yield

8. Impact of background ozone on crop yield in 2030 Feng & Kobayashi (2009)

9. Acute v Chronic Ozone Exposure Acute –Exposure to high concentrations (>120 ppb) for several hours –Uncontrolled cell & tissue death Chronic –Exposure to an elevated background concentration (daily peaks 40 - 120 ppb) –Often no visible symptoms –Decreased photosynthesis, accelerated senescence

10. O3O3 guard cell cuticle mesophyll epidermis stoma chloroplast

11. O3O3 damaging oxidants vitamin C signaling ethylenejasmonateaspirin Reduced photosynthesis Accelerated senescence Improved defense against O 3

12. nucleus Repair & protection pathways signaling O3O3 damaging oxidants vitamin C

13. O3O3 damaging oxidants vitamin C nucleus Repair & protection pathways signaling Changes to the cell wall

14. sugar & starch energy rubisco chloroplast CO 2 light reactions dark reactions protease O3O3 damaging oxidants vitamin C signaling

15. 0 100 0 50 150 % control 481216 Time (h) light reactions rubisco activity dark reactions Long & Naidu (2002) Impact of acute ozone exposure on photosynthesis

16. 0 100 50 150 % control light reactions rubisco content stomatal conductance Long & Naidu (2002) Impact of chronic ozone exposure on photosynthesis in wheat completion of leaf expansion early grain fill late grain fill

17. Impact of chronic ozone exposure on photosynthesis in soybean Fiscus et al (2005)

18. O3O3 damaging oxidants vitamin C signaling nucleus photosynthetic gene transcription senescence associated gene transcription accelerated senescence

19. Leaf area index CO 2 Control O 3 Demody et al (2006) www.soyface.illinois.edu

20. Summary reduced photosynthesis + reduced leaf area = reduced productivity

21. How can plants better adapt to ozone? Control ozone entry into the leaf –reduced stress v reduced productivity Alter the signal transduction pathway –Reduced sensitivity v decreased resistance to pests & pathogens Improve detoxification Reproductive tissue is still vulnerable Ainsworth et al (2008)