الفهرس 
1. INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Two aspects of global climate change that directly influence plant physiology, growth
and productivity; namely they are an increase in ambient ozone concentration (O3) and a
rising atmospheric carbon dioxide concentration ([CO2]) (Ainsworth et al., 2008; Hassan,
2010). Atmospheric CO2 is projected to continue rising to at least 550 ppb by 2050
(Solomon et al., 2007). The current annual average (O3) ranges from 20 ppb to 45 ppb
across the globe, which is roughly, double the concentration that preceded the Industrial
Revolution (Vingarzan, 2004). Background [O3] is predicted to continue increasing by 0.5–
2% per year over the next century, mainly due to increases in precursor emissions from
anthropogenic sources (Solomon et al., 2007). While CO2 is well mixed in the atmosphere,
O3 is a spatially and temporally heterogeneous pollutant and local concentrations depend
heavily on upwind precursor emissions and local O3
- generating environmental conditions.
Short periods of very high [O3] can occur in rural areas and have the potential to cause
marked damage to foliage (The Royal Society, 2008).
Currently, O3 is considered to be the most important air pollutant affecting the
plant productivity in every part of the world (Mittal et al., 2007; Feng et al., 2008, 2011;
Tiwari and Agrawal, 2009). Modelling-based studies in Asian regions showed greater risk
to agriculture in Asia leading to yield losses of 5–20% for important crops (wheat, rice and
legumes) in areas experiencing elevated O3 concentrations (Emberson et al., 2009).