Evaluation of the effects of ozone on yield of Japanese rice (Oryza sativa L.) based on stomatal ozone uptake

To evaluate the negative impact of ozone (O-3) on Japanese crop plant yield based on cumulative stomata! O-3 flux, a Japanese rice cultivar, Koshihikari, was exposed to O-3 in O-3-exposure chambers. Stomatal diffusive conductance to water vapour were measured during the experimental period. We parameterized and improved a stomatal diffusive conductance model by considering seasonal changes in stomatal diffusive conductance, as well as the acute effects of O-3 on this variable. Our adjusted model accounted for 64% of the variation within the data set. Based on the results of linear regression analyses of the relationship between relative yield and cumulative O-3 uptake, the negative impact of O-3 on the yield of Koshihikari can be evaluated using cumulative O-3 uptake with a threshold of 10 nmol O-3 m(-2) projected leaf area s(-1) and an integration period of -300 to 100 degrees C days from anthesis. (C) 2013 Elsevier Ltd. All rights reserved.