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Acclimation to future atmospheric CO 2 levels increases photochemical efficiency and mitigates photochemistry inhibition by warm temperatures in wheat under field chambers
Author(s) -
Gutiérrez Diego,
Gutiérrez Elena,
Pérez Pilar,
Morcuende Rosa,
Verdejo Angel L.,
MartinezCarrasco Rafael
Publication year - 2009
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.2009.01256.x
Subject(s) - anthesis , chemistry , photochemistry , chlorophyll fluorescence , carbon dioxide , electron transport chain , photosynthesis , quantum yield , horticulture , biology , fluorescence , biochemistry , physics , organic chemistry , quantum mechanics , cultivar
A study was conducted over 2 years to determine whether growth under elevated CO 2 (700 μmol mol −1 ) and temperature (ambient + 4 °C) conditions modifies photochemical efficiency or only the use of electron transport products in spring wheat grown in field chambers. Elevated atmospheric CO 2 concentrations increased crop dry matter at maturity by 12–17%, while above‐ambient temperatures did not significantly affect dry matter yield. In measurements with ambient CO 2 at ear emergence and after anthesis, growth at elevated CO 2 concentrations decreased flag leaf light‐saturated carbon assimilation. The quantum yield of electron transport (Φ PSII ) measured at ambient CO 2 and higher irradiances increased at ear emergence and decreased after anthesis in plants grown at elevated CO 2 . At higher light intensities, but not in low light, photochemical quenching (qP) decreased after growth in elevated CO 2 conditions. Growth under CO 2 enrichment increased dark‐ (Fv:Fm) and light‐adapted (Fv′:Fm′) photochemical efficiencies, and decreased the chlorophyll a : b ratio, suggesting an increase in light‐harvesting complexes relative to PSII reaction centres. A relatively higher decrease in carbon assimilation than the decrease in Φ PSII pointed to a sink other than CO 2 assimilation for electron transport products at defined growth stages. With higher light intensities, warmer temperatures increased Φ PSII and Fv′:Fm′ at ear emergence and decreased Φ PSII after anthesis; in ambient—but not elevated—CO 2 , warmer temperatures also decreased qP after anthesis. CO 2 fixation increased or did not change with temperature, depending on the growth stage and year. We conclude that elevated CO 2 decreases the carbon assimilation capacity, but increases photochemistry and resource allocation to light harvesting, and that elevated levels of CO 2 can mitigate photochemistry inhibition as a result of warm temperatures.