or non-stomatal limitations. In the present study, despite the
decreases inAmatching those ofgsin inoculated plants, the
slight increase in Ci implies that the major limitation to
photosynthesis must be attributed to direct effects of the
infection at the chloroplast level.
In conclusion, the results from the present study
demonstrated that the infectious process ofB. oryzaeon
rice affected leaf physiology mainly through the damage to
the cells, especially at the membrane level. Despite the
strong decreases in gs, the fungus-induced changes in
photosynthesis were largely related to both impaired light
capture ability and decreased mesophyll capacity to fix
CO2. Taking the plant as whole, the overall decreased
photosynthetic productivity in response to the disease also
results from a decreased amount of healthy leaf area. In
fact, the reduction on photosynthetic activity on diseased
leaves occurred in close association with chlorophylls
breakdown as indicated by the continuous yellowing of
the photosynthetic leaf tissue