Details

Autor(en) / Beteiligte

• Leipner, Jorg
• Oxborough, Kevin
• Baker, Neil R

Titel

Plants and the Environment. Primary sites of ozone-induced perturbations of photosynthesis in leaves: identification and characterization in Phaseolus vulgaris using high resolution chlorophyll fluorescence imaging

Ist Teil von

• Journal of experimental botany, 2001-08, Vol.52 (361), p.1689

Ort / Verlag

Oxford: Oxford Publishing Limited (England)

Erscheinungsjahr

2001

Link zum Volltext

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• 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 [mu]mol 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.