Tg. Reichenauer et Hr. Bolhar-nordenkampf, Mechanisms of impairment of the photosynthetic apparatus in intact leaves by ozone, Z NATURFO C, 54(9-10), 1999, pp. 824-829
Citations number
49
Categorie Soggetti
Biochemistry & Biophysics
Journal title
ZEITSCHRIFT FUR NATURFORSCHUNG C-A JOURNAL OF BIOSCIENCES
Tropospheric ozone has been recognised as a limiting factor for plant growt
h since late fifties of our century. The decrease in the rate of light satu
rated net photosynthesis (A(sat)) was shown to be the major effect of ozone
in leaves with negative consequences for plant growth and the development
of plant communities. The reasons for the ozone-induced decrease in A(sat)
are still under investigation. Possible mechanisms are an increasing stomat
al limitation, an increase in mesophyll limitation including a reduction of
the CO2 fixation in the Calvin cycle and an impairment of the photochemica
l reactions in the grana membranes of chloroplasts. We conclude from the re
viewed literature and from our own experiments that a decrease in carboxyla
tion efficiency (CE) seems to be an early event caused by ozone leading to
a decrease in A(sat). The loss in current photochemical capacity (F-v/F-m)
appears with a lag phase of many days and therefore the loss is thought to
be a secondary effect due to a decreased demand of 'assimilatory power'.