Effects of elevated CO_2 and O_3 on aspen clones varying in O_3 sensitivity: can CO_2 ameliorate the harmful effects of O_3?

摘要

To determine whether elevated CO_2 reduces or exacerbates he detrimental effects of O_3 aspen(Populus tremuloies Michx.), aspen clones 216 and 271(O_3 tolerant), and 259(O_3 sensitive)were exposed to ambient levels of CO_2 and O_3 or elevated levels of CO_2, O_3 or CP_2 + O_3 in the FACTSⅡ(Aspen FACE)experiment, and physiological and molecular responses were measured and Compared. Clone 259, the most O_3-sensitive clone, showed the greatest amount of visible foliar symptoms as well as significant Decreases in chlorophyll, carotenoid, starch, and ribulose-1,5-bisphosphate carboxylase/oxygenase(Rubisco)concentrations and Transcriptionw levels for the Rubisco small subunit.