Effects of chronic elevated ozone concentration on antioxidant capacity, photosynthesis and seed yield of 10 soybean cultivars

Abstract

Crops losses to tropospheric ozone (O3) in the United

Effects of elevated O3 exposure on seed yield, N concentration and photosynthesis of nine soybean cultivars (Glycine max (L.) Merr.) in Northeast China

“…Compared with CF, E-O 3 induced a reduction of 40% in seed yield across all cultivars (Table 2), which is an unexpected greater than that in a meta-analysis result of 24% from 53 peer-reviewed studies exposed to an average O 3 concentration of 70 ppb [3]. One explanation for the larger unexpected yield losses might be the photosynthesis of these cultivars in the current experiment much more sensitive to O 3 stress, compared with those10 Mid-western cultivars in USA [23]. Furthermore, the greater yield loss might be ascribed to non-limiting growth conditions, especially the high humidity of approximately 80% in chambers.…”

“…Accelerated leaf senescence was the most typical symptoms by elevated O 3 [2,37], which is regulated by processes involving chlorophyll degradation and leaf nutrient status [23,38,39]. In this study, E-O 3 significantly decreased net photosynthetic rate (45%) in all cultivars at flowering stage after about 15 consecutive exposure days, suggesting that the photosynthesis unit of soybean is very sensitive to O 3 .…”

“…However, the relationship between O 3 -induced changes in leaf N content and photosynthesis rate response is scare for those N fixation species. The underlying mechanisms responsible for decreased photosynthesis and C assimilation by O 3 varies among soybean cultivars (or genetic variation) [21,23]. Moreover, O 3 had larger effects on reproductive stage than vegetative stage for sensitive soybean cultivars [3], possibly due to larger O 3 accumulation and less N pool at reproductive stage [3,24].…”

Differential effects of ozone on photosynthesis of winter wheat among cultivars depend on antioxidative enzymes rather than stomatal conductance

“…However, the varietal difference in response to E-O 3 was observed only at the latest developmental stage (mid-grain filling), implying accumulative O 3 effects. It is consistent with previous chamber studies of wheat plants (Feng et al, 2008), as well as with SoyFACE experiments using ten soybean cultivars (Betzelberger et al, 2010). At the final measurement stage, O 3 -induced reduction of A sat was significant in Y19, Y2 and Y15 but not in J2 and Y16 (Fig.…”

“…acute vs. chronic ozone exposure (Baier et al, 2005;Betzelberger et al, 2010;Burkey et al, 2003;Feng et al, 2011;Kollist et al, 2000;Wang et al, 2014aWang et al, , 2014b. In general, acute exposure to relatively high O 3 concentrations often caused leaf lesions resulting from programmed cell death associated with plant-pathogen interaction (Kangasjarvi et al, 2005;Overmyer et al, 2003;Rao et al, 2000) and induces an increase in antioxidant metabolism (Conklin and Barth, 2004;Kangasjarvi et al, 1994).…”