Air in
filtered chambers (ACO2) was passed through charcoal
filters to reduce ambient O3 concentrations by 84–90%. All the
chambers were provided with prefilters to remove the dust.
Ambient and elevated concentrations of CO2 were administered
24 h daily, whereas elevated O3 was given 8 h daily from 9:30 am to
4:30 pm during the day time. Both CO2 and O3 treatments were
started after emergence and continued till the maturity of the
potato crop. The experiment was performed using randomized
block design. There were two replication of each treatment
randomly distributed within the whole plot. CO2 was supplied
through CO2 cylinder having connection in air delivery system of
OTCs, attached to the high speed blowers. The CO2 concentration
was regulated by dilution with air stream generated by blower. The
concentration of CO2 in the chamber was monitored just above the
crop canopy using CO2 analyzer (Model LI-820, LI-COR Biosciences,
Lincoln, USA).