Ozone and Planetary Food Security: The Bad News and Good News
Wilkinson, S., Mills, G., Illidge, R. and Davies, W.J. 2012. How is ozone pollution reducing our food supply? Journal of Experimental Botany 63: 527-536.
The bad news, as the four researchers describe it, is the fact that "ozone causes visible injury symptoms to foliage; it induces early senescence and abscission of leaves; it can reduce stomatal aperture and thereby carbon uptake, and/or directly reduce photosynthetic carbon fixation; it can moderate biomass growth via carbon availability or more directly; it can decrease translocation of fixed carbon to edible plant parts (grains, fruits, pods, roots) due either to reduced availability at source, redirection to synthesis of chemical protectants, or reduced transport capabilities via phloem; decreased carbon transport to roots reduces nutrient and water uptake and affects anchorage; ozone can moderate or bring forward flowering and induce pollen sterility; it induces ovule and/or grain abortion; and finally it reduces the ability of some genotypes to withstand other stresses such as drought, high vapor pressure deficit, and high photon flux density via effects on stomatal control."
The good news, as described in several journal reviews on the NIPCC website (see Interactive Effects of CO2 and Ozone on Plant Growth), is that the ongoing rise in the air's CO2 content tends to negate all of the bad news.