Differences in responses of two mustard cultivars to ethylenediurea (EDU) at high ambient ozone concentrations in India

Assessing the effects of ambient ozone in China on snap bean genotypes by using ethylenediurea (EDU)

“…AOT40 was 29.04 ppm.h, which exceeded by far both the AOT40 threshold established by WHO (3 ppm.h for 3 months) for agricultural crops (Roy et al, 2009), and the ozone critical level for most sensitive or moderately sensitive crop plants (8.6 ppm.h for a 3-month growing season) . With such high ozone levels occurring recurrently year after year, Beijing area is undoubtedly an important hotspot for this pollutant, only comparable (but above) to different parts of India Singh and Agrawal, 2011;Oksanen et al, 2013;Pandey et al, 2014;Singh et al, 2014), and with concentrations much above other parts of the world. In the short term, this situation is expected to last for years, and even to worsen as, contrary to USA and Europe, ozone precursors (mainly NO x ) are currently increasing in China at an annual rate of 5% (Feng et al, 2015).…”

“…The application of EDU as a 'control' to ambient ozone is useful to determine ambient ozone effects in fieldgrown plants, particularly in many remote and developing regions where electricity and funding are limited (Blum et al, 1998;Hassan et al, 1995;Manning et al, 2011;Tiwari and Agrawal, 2010). EDU is regarded to act in the apoplast as a potential chemical scavenger (Gatta et al, 1997), thus protecting plants from ozone injury by increasing the antioxidant capacity of the leaf (Pandey et al, 2014;Singh et al, 2009;Tiwari and Agrawal, 2010).…”

Associational susceptibility in broccoli: mediated by plant volatiles, impeded by ozone

“…At present, background ozone concentrations in the northern hemisphere are in the range of 35–40 nmol mol −1 , but peak ozone concentrations commonly exceed 100 nmol mol −1 and occasionally reach 200 nmol mol −1 (The Royal Society, ). The Indo‐Gangetic plain of South Asia is of particular vulnerability to ozone pollution, with 8‐h daily averages occasionally exceeding levels of 80 nmol mol −1 (Pandey et al ., ), while in the Beijing area of China, visible symptoms of ozone stress have been observed in 28 different plant species (Feng et al ., ). The reactivity and phytotoxicity of ozone make it a significant gas with respect to the function of plant–plant interactions, especially in more polluted areas (Holopainen & Blande, ; Blande et al ., ).…”

Effects of the Antiozonant Ethylenediurea (EDU) on Fraxinus ornus L.: The Role of Drought

“…In fact, although drought is known to protect plants from O 3 by inducing stomatal closure [11,59], recent studies have highlighted that, under certain conditions, drought can instead increase plant sensitivity to O 3 [13], particularly if it occurs later in the season, after O 3 uptake during spring [14]. It has frequently been reported that EDU is able to ameliorate oxidative stress through different mechanisms, involving the inhibition of Reactive Oxygen Species (ROS) production [64] or the enhancement of both enzymatic and non-enzymatic ROS-scavenging mechanisms [17,35,53]. In particular, EDU has been reported to support the ascorbate-glutathione cycle (or Halliwell-Asada cycle), which involves apoplastic ascorbate peroxidase (APX) and symplastic glutathione reductase (GR) [65].…”

“…However, the protective mechanism of EDU is still not fully understood [18]. Some studies [34][35][36] have shown that EDU acts by maintaining a high antioxidant enzyme activity and level during O 3 exposure, but other studies concluded that EDU does not significantly affect the antioxidant content in leaves [24]. It is also unclear whether EDU limits stomatal O 3 uptake by inducing a decrease in the stomatal conductance of treated plants [16,17].…”