| contact
leipner photosynthesis consulting
Dr. Jörg Leipner
Neumattstrasse 2
4450 Sissach
SWITZERLAND
email: leipner@photosynthesis.ch
mobile: +41 78 817 3559
|
Applications
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. Dashed white lines
indicate the position of stomata. |
|
examples
Screening for chilling tolerance of maize
seedlings
[further information]
Discriminating winter wheat for frost
tolerance
[further information]
Detecting ozone damage in Phaseolus
[further information]
|
