leipner photosynthesis consulting

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leipner photosynthesis consulting
Dr. Jörg Leipner
Neumattstrasse 2
4450 Sissach

email: leipner@photosynthesis.ch
mobile: +41 78 817 3559


Detecting ozone damage in Phaseolus

High resolution imaging of chlorophyll fluorescence can be used to identify the sites at which ozone initially induces perturbations of photosynthesis in leaves. In a study at the University of Essex, leaves of Phaseolus vulgaris were exposed to 250 and 500 μmol mol-1 ozone at a photosynthetically active photon flux density of 300 μmol m-2 s-1 for 3 h (Leipner et al., 2001). 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.

Fv/Fm image of the upper leaf surface of a bean leaf treated with ozone
Fv/Fm image of the upper leaf surface of a bean leaf treated with ozone. Dashed white lines indicate the position of stomata.

Chlorophyll fluorescence measurements in winter wheat


Screening for chilling tolerance of maize seedlings
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Discriminating winter wheat for frost tolerance
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Detecting ozone damage in Phaseolus
[further information]

© 2010 jl