Effects of ozone on growth, yield and leaf gas exchange rates of four Bangladeshi cultivars of rice (Oryza sativa L.)

Abstract To assess the effects of tropospheric O 3 on rice cultivated in Bangladesh, four Bangladeshi cultivars (BR11, BR14, BR28 and BR29) of rice ( Oryza sativa L.) were exposed daily to charcoal-filtered air or O 3 at 60 and 100 nl l −1 (10:00–17:00) from 1 July to 28 November 2008. The whole-plant dry mass and grain yield per plant of the four cultivars were significantly reduced by the exposure to O 3 . The exposure to O 3 significantly reduced net photosynthetic rate of the 12th and flag leaves of the four cultivars. The sensitivity to O 3 of growth, yield and leaf gas exchange rates was not significantly different among the four cultivars. The present study suggests that the sensitivity to O 3 of yield of the four Bangladeshi rice cultivars is greater than that of American rice cultivars and is similar to that of Japanese rice cultivars and that O 3 may detrimentally affect rice production in Bangladesh.