Interactive effects of elevated CO2 and ozone on leaf thermotolerance in field-grown glycine max

Sasmita Mishra, Scott A. Heckathorn, Deepak Barua, Dan Wang, Puneet Joshi, E. William Hamilton, Jonathan Frantz

Research output: Contribution to journalArticlepeer-review

21 Scopus citations

Abstract

Humans are increasing atmospheric CO2, ground-level ozone (O3), and mean and acute high temperatures. Laboratory studies show that elevated CO2 can increase thermotolerance of photosynthesis in C3 plants. O3-related oxidative stress may offset benefits of elevated CO2 during heat-waves. We determined effects of elevated CO2 and O3 on leaf thermotolerance of field-grown Glycine max (soybean, C3). Photosynthetic electron transport (Φet) was measured in attached leaves heated in situ and detached leaves heated under ambient CO2 and O3. Heating decreased Φet, which O3 exacerbated. Elevated CO2 prevented O3-related decreases during heating, but only increased Φet under ambient O3 in the field. Heating decreased chlorophyll and carotenoids, especially under elevated CO2. Neither CO2 nor O3 affected heat-shock proteins. Heating increased catalase (except in high O3) and Cu/Zn-superoxide dismutase (SOD), but not Mn-SOD; CO2 and O3 decreased catalase but neither SOD. Soluble carbohydrates were unaffected by heating, but increased in elevated CO2. Thus, protection of photosynthesis during heat stress by elevated CO2 occurs in field-grown soybean under ambient O3, as in the lab, and high CO2 limits heat damage under elevated O3, but this protection is likely from decreased photorespiration and stomatal conductance rather than production of heat-stress adaptations.

Original languageEnglish
Pages (from-to)1396-1405
Number of pages10
JournalJournal of Integrative Plant Biology
Volume50
Issue number11
DOIs
StatePublished - 2008

Keywords

  • Anti-oxidants
  • Global change
  • Heat-shock proteins
  • Photosynthesis

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