Primary sites of ozone‐induced perturbations of photosynthesis in leaves: identification and characterization in Phaseolus vulgaris using high resolution chlorophyll fluorescence imaging

• Published in: Journal of experimental botany 2001-08, Vol.52 (361), p.1689-1696
• Main Authors: Leipner, Jörg, Oxborough, Kevin, Baker, Neil R.
• Format: Article
• Language: English
• Subjects: 10pt; Animal, plant and microbial ecology; Applied ecology; batchmode \documentclass[fleqn; Biological and medical sciences; Chlorophyll - metabolism; Chlorophylls; Diagnostic Imaging - methods; difference in fluorescence between \batchmode \documentclass[fleqn; Ecotoxicology, biological effects of pollution; Effects of pollution and side effects of pesticides on plants and fungi; Electron transport; Fabaceae - cytology; Fabaceae - drug effects; Fabaceae - metabolism; Fluorescence; fluorescence imaging; fluorescence level in the light; Fundamental and applied biological sciences. Psychology; Guard cells; High resolution; Imaging; legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathit{F}_{\mathrm{q}}\) \end{document}=\batchmode \documentclass[fleqn; legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathit{F}{^\prime}_{\mathrm{m}}\) \end{document}; legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathit{F}{^\prime}_{\mathrm{m}}\) \end{document} and F (\batchmode \documentclass[fleqn; legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathit{F}{^\prime}_{\mathrm{m}}\) \end{document}−F; legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathit{F}{^\prime}_{\mathrm{q}}\) \end{document}; Light-Harvesting Protein Complexes; maximal fluorescence level from dark‐adapted leaves; maximal fluorescence level from leaves in light; Mesophyll cells; minimal fluorescence level from dark‐adapted leaves; Non agrochemicals pollutants; Ozone; Ozone - pharmacology; Phaseolus vulgaris; Photosynthesis; Photosynthesis - drug effects; Photosynthesis - radiation effects; Photosynthetic Reaction Center Complex Proteins - drug effects; Photosynthetic Reaction Center Complex Proteins - metabolism; Photosystem II Protein Complex; Phytopathology. Animal pests. Plant and forest protection; Plant cells; Plant Epidermis - cytology; Plant Epidermis - drug effects; Plant Epidermis - metabolism; Plant Leaves - cytology; Plant Leaves - drug effects; Plant Leaves - metabolism; Plants and the Environment; Plants, Medicinal; Pollution effects and side effects of agrochemicals on crop plants and forest trees. Other anthropogenic factors; Pollution effects. Side effects of agrochemicals; Quantum Theory; Stomata; stomatal conductance; variable fluorescence level from dark‐adapted leaves (Fv=Fm−Fo)
• ISSN: 0022-0957; 1460-2431; 1460-2431
• DOI: 10.1093/jexbot/52.361.1689

High resolution imaging of chlorophyll a fluorescence was used to identify the sites at which ozone initially induces perturbations of photosynthesis in leaves of Phaseolus vulgaris. Leaves were exposed to 250 and 500 nmol mol−1 ozone at a photosynthetically active photon flux density of 300 μmol m−2 s−1 for 3 h. Images of fluorescence parameters indicated that large decreases in both the maximum and operating quantum efficiencies of photosystem II had occurred in cells adjacent to stomata in the upper, but not lower, leaf surfaces. However, this treatment did not produce any significant changes in the maximum or operating quantum efficiencies of photosystem II in the leaves when estimated from fluorescence parameters measured with a conventional, integrating fluorometer. The localized decreases in photosystem II photochemical efficiencies were accompanied by an increase in the minimal fluorescence level, which is indicative of photoinactivation of photosystem II complexes and a decrease in stomatal conductance. Perturbations of photochemical efficiencies were not observed in cells associated with all of the stomata on the upper leaf surface or within cells distant from the upper leaf surface. It is concluded that ozone penetrates the leaf through stomata and initially damages only cells close to stomatal pores.