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Photosynthesis of two poplar clones under long‐term exposure to ozone
Author(s) -
Soldatini Gian Franco,
Lorenzini Giacomo,
Filippi Ferruccio,
Nali Cristina,
Guidi Lucia
Publication year - 1998
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1034/j.1399-3054.1998.1040427.x
Subject(s) - photosynthesis , chlorophyll fluorescence , stomatal conductance , ozone , botany , electron transport chain , chemistry , quenching (fluorescence) , chlorophyll , biology , horticulture , photochemistry , fluorescence , biophysics , physics , organic chemistry , quantum mechanics
The photosynthetic response was studied in two clones ( Populus deltoides × maximowiczii Eridano and Populus × euramericana I‐214), known for their differential response to ozone (O 3 ) in terms of visible symptoms, when exposed to O 3 (60 nl l −1 5 h day −1 , 7 and 15 days). The photosynthetic ability was tested using gas exchange and chlorophyll fluorescence analysis. O 3 caused a decrease in the CO 2 assimilation rate at light saturation level in mature leaves of both clones. Alterations of Chl fluorescence parameters, in particular the F v /F m ratio and non‐photochemical quenching were also observed. The effects were similar for both clones and it could not be concluded that differential effects on electron transport capacity were responsible for the observed reduction in photosynthesis. The reduction of photosynthetic rate in Eridano was due mainly to a reduced mesophyll activity, as evidenced by the increase in intercellular CO 2 concentration and the minimal changes in stomatal conductance. In contrast, in I‐214, stomatal effects were primarily responsible, although effects on the mesophyll cannot be excluded. Data obtained indicate that the effects observed at the mesophyll level may be attributed to indirect effects caused by membrane disorders.