Ethylenediurea Research Articles

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

Four genotypes of snap bean (Phaseolus vulgaris L.) were selected to study the effects of ambient ozone concentration at a cropland area around Beijing by using 450 ppm of ethylenediurea (EDU) as a chemical protectant. During the growing season, the 8h (9:00–17:00) average ozone concentration was very high, approximately 71.3 ppb, and AOT40 was 29.0 ppm.h. All genotypes showed foliar injury, but ozone-sensitive genotypes exhibited much more injury than ozone-tolerant ones. Compared with control, EDU significantly alleviated foliar injury, increased photosynthesis rate and chlorophyll a fluorescence, Vcmax and Jmax, and seed and pod weights in ozone-sensitive genotypes but not in ozone-tolerant genotypes. EDU did not significantly affect antioxidant contents in any of the genotypes. Therefore, EDU effectively protected sensitive genotypes from ambient ozone damage, while protection on ozone-tolerant genotypes was limited. EDU can be regarded as a useful tool in risk assessment of ambient ozone on food security.

Searching for common responsive parameters for ozone tolerance in 18 rice cultivars in India: Results from ethylenediurea studies

Eighteen rice (Oryza sativa) cultivars were screened for ozone (O3) tolerance and for the most responsive parameters with ethylenediurea (EDU) treatments at two experimental sites experiencing high ambient O3 conditions in the Indo-Gangetic Plains (IGP) of India. EDU was applied at 15day intervals until the final harvest phase as a foliar spray at 300ppm in order to protect the plants from the adverse effects of O3. Antioxidant activity, malondialdehyde content (MDA), chlorophyll content, gas exchange, and chlorophyll fluorescence (Fv/Fm) at the vegetative and flowering phases and harvest-related parameters were studied, for a total of 24 parameters. Seven of the studied cultivars had higher than average grainweightplant−1 in all site and treatment combinations and can be recommended for cultivation in areas suffering from high O3 concentrations. The most responsive parameters with EDU treatment in high O3 across all cultivars were superoxide dismutase (SOD) and catalase (CAT) activities, the contents of oxidised (GSSG) and reduced (GSH) glutathione and MDA, and shoot weight plant−1. These results indicated that the O3 scavenging activity of EDU is mediated through an antioxidant defence system rather than a direct effect on physiological parameters, such as photosynthesis and stomatal conductance.

Ethylene-di-urea (EDU), an effective phytoproctectant against O<sub>3</sub> deleterious effects and a valuable research tool

Ground-surface ozone (O3) has been increasing over the last decades, and it is now well known that crop and forestry plants suffer from elevated O3 levels. Ethylene-di-urea (EDU) is considered a chemical that offers protection to the treated plants against Ο3. Increasing evidence on the antiozonate efficacy of EDU against the phytotoxic action of O3 is becoming more readily available. We aimed to review the current literatures on the EDU effects on plants, summarize the findings, note any problems, and formulate conclusions from the existing researches. EDU is a very promising antiozonant with its antiozonate action being observed when applied to roots in the concentrations of 275.7 to 374.3 mg L-1, or on leaves in the concentrations of 365.1 to 519.5 mg L-1. There is an evidence that EDU was more effective in some cultivars compared with others although this remains inexplicable. Additionally, the biochemical mechanism of its antiozonate activity is not well understood and requires parallel toxicological studies. In summary, EDU must play an important role in O3 research in the future.

Ethylenediurea (EDU) as a soil drench to reduce O3 impact on willow (Salix sachalinensis) cuttings: A preliminary observation using a free-air O3 fumigation system

Ethylenediurea (EDU) as a soil drench to reduce O3 impact on willow (Salix sachalinensis) cuttings: A preliminary observation using a free-air O3 fumigation system

Willow cuttings grown under elevated O3 and treated by ethylenediurea (EDU): a free-air O3 fumigation system

Willow cuttings grown under elevated O3 and treated by ethylenediurea (EDU): a free-air O3 fumigation system

Application of ethylene diurea (EDU) in assessing the response of a tropical soybean cultivar to ambient O3: Nitrogen metabolism, antioxidants, reproductive development and yield

The present study deals with assessment of response of a tropical soybean cultivar to O3 in relation to photosynthetic pigments, chlorophyll fluorescence kinetics, antioxidative capacity, N assimilation enzymes, metabolites, growth and yield using ethylene diurea (EDU) given as a soil drench (400) ppm at an interval of 10 days after germination up to maturity. Mean O3 concentration was 42ppb and accumulated threshold above 40ppb (AOT 40) was 9.07ppmh. Lipid peroxidation and total phenolics reduced, while increases in activities of antioxidative and nitrogen assimilation enzymes, ascorbic acid, protein, photosynthetic pigments, Fv/Fm ratio, number of leaves, flowers, pods, branches and yield attributes were found in EDU treated plants. EDU alleviated the negative effects of O3 by enhancing the first line of defense against ROS and protecting N assimilation enzymes at flowering and maintaining adequate supply of photosynthates to developing pods during pod filling stage. EDU provided maximum protection between flowering to pod filling stage.

Assessment of ethylene diurea-induced protection in plants against ozone phytotoxicity.

Urbanization, industrialization and unsustainable utilization of natural resources have made tropospheric ozone (03) one of the world's most significant air pollutants. Past studies reveal that 0 3 is a phytotoxic air pollutant that causes or enhances food insecurity across the globe. Plant sensitivity, tolerance and resistance to 0 3 involve a wide array of responses that range from growth to the physiological, biochemical and molecular. Although plants have an array of defense systems to combat oxidative stress from 0 3 exposure, they still suffer sizable yield reductions. In recent years, the ground-level 0 3 concentrations to which crop plants have been exposed have caused yield loses that are economically damaging. Several types of chemicals have been applied or used to mitigate the effects produced by 0 3 on plants. These include agrochemicals (fungicides, insecticides, plant growth regulators), natural antioxidants, and others. Such treatments have been effective to one degree to another, in ameliorating Or generated stress in plants. Ethylene diurea (EDU) has been the most effective protectant used and has also served as a monitoring agent for assessing plant yield losses from 0 3 exposure. In this review, we summarize the data on how EDU has been used, the treatment methods tested, and application doses found to be both protective and toxic in plants. We have also summarized data that address the nature and modes of action (biophysical and biochemical) of EDU. In general, the literature discloses that EDU is effective in reducing ozone damage to plants, and indicates that EDU should be more widely used on 0 3 sensitive plants as a tool for biomonitoring of 0 3 concentrations. Biomonitoring studies that utilize EDU are very useful for rural and remote areas and in developing countries where 0 3 monitoring is constrained from unavailability of electricity. The mechanism(s) by which EDU prevents 0 3 toxicity in plants is still not completely known. EDU possesses great utility for screening plant sensitivity under field conditions in areas that experience high 0 3 concentrations, because EDU prevents 0 3 toxicity only in 0 3 sensitive plants. Ozone-resistant plants do not respond positively to EDU applications. However, EDU application dose and frequency must be standardized before it can be effectively and widely used for screening 0 3 sensitivity in plants. EDU acts primarily by enhancing biochemical plant defense and delaying Or induced senescence, thereby reducing chlorophyll loss, and maintaining physiological efficiency and primary metabolites; these actions enhance growth, biomass and yield of plants. We believe that future studies are needed to better address the EDU dose response relationship for many plant species, and to screen for new cultivars that can resist 0 3 stress. Although some research on the physiological and biochemical mechanisms of action of EDU have been performed, the new 'omics' tools have not been utilized to evaluate EDUs mechanism of action. Such data are needed, as is gene expression and proteome profiling studies on EDU-treated and -untreated plants.

Evaluation of Di-1-p-Menthene as Antiozonant on Bel-W3 Tobacco Plants, as Compared with Ethylenediurea

Tropospheric ozone (O3) has long been documented to cause an injury to plants, but a plants’ protectant, widely applicable in agronomical practice, does not exist. We evaluated the potential antiozonate efficacy of the antitranspirant di-1-p-menthene (Vapor Gard) compared with ethylenediurea (EDU) on Bel-W3 tobacco plants. Plants were treated either with water, or by EDU (10, 100, and 500 mg dm−3), or by vapor (1, 5, 10, and 50 ml dm−3) and were exposed either to O3-enriched (90 ppb) or O3-free air, for 12 days and 8 h day−1. EDU when applied at 10 mg dm−3 did not protect the plants against O3, but when applied at 100 and 500 mg dm−3 offered a significant protection to the plants. Vapor, when applied at 1 ml dm−3 did not protect the plants against O3, neither by terms of foliar visible injury nor by terms of aboveground biomass. In addition, when applied at 10 and 50 ml dm−3 caused phytotoxicity to all the plants, which it was expressed as necrotic spots on the leaves’ surface, misshaping of the leaves, or short plants' height. It is obvious that vapor does not protect Bel-W3 tobacco plants against O3. The antiozonate role of di-1-p-menthene is species-specific and probably occurs only under short-term exposures.

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

Ethylenediurea (EDU) at two different concentrations (200ppm and 400ppm) was used as a tool to study the response of two local Indian cultivars (Kranti and Peela sona) of mustard (Brassica rapa syn. B. campestris) to ambient ozone conditions. During the experiment, the critical AOT 40 levels were exceeded in the area of study in the Indo-Gangetic plains. Seed weight, biomass, oil content of the seeds and chlorophyll content increased at both EDU treatment levels in both cultivars. Gas exchange parameters (stomatal conductance and photosynthesis) were not affected by the EDU treatment, while the responses of antioxidative enzymes varied between the cultivars. The results indicate that EDU-induced ozone protection in these mustard cultivars is mediated by an antioxidative defense system, and that the cultivars adopted different strategies against ozone stress. The cultivar Kranti, characterized by higher biomass accumulation and number of pods, showed stronger antioxidative defense through several enzymes throughout the experiment, whereas the cultivar Peela sona, characterized by earlier senescence and a greater resource allocation to seed weight, invested in enzymatic detoxification only during the vegetative phase. The seed oil content increased by 4–5% at higher EDU treatment in both cultivars, which causes concern for mustard oil production at current ozone levels in India. Obviously, wider screening, using controlled ozone treatments, of B. campestris cultivars is urgently needed in order to maintain and improve the production rates in this highly populated and polluted area of India.

Gene expression in snapbeans exposed to ozone and protected by ethylenediurea

Ethylenediurea (EDU) is the most common chemical used to prevent ozone (O3) injury on vegetation. Despite considerable research, its mode of action remains elusive and gene expression has not been studied. Transcripts of major antioxidant enzymes (catalase, glutathione reductase, glutathione peroxidase) were measured for the first time in a model plant (Phaseolus vulgaris cv S156) after short-term O3 exposure (0 or 90 ppb, 5 h/d, 4 days) and a single spray with EDU (0 or 300 ppm). Visible, physiological and biochemical parameters were assessed as indices of O3-induced stress. In O3-exposed EDU-protected plants, levels of transcript, enzyme activity, H2O2 accumulation, gas exchange and foliar visible injury were similar to those in control plants. These results suggest that EDU may halt the O3-induced ROS generation within 24 h from the exposure, and thus the downstream cascade mechanisms leading to increased H2O2 production, impaired gas exchange, and occurrence of leaf lesions.

Mycorrhizal status of an ozone-sensitive poplar clone treated with the antiozonant ethylene diurea

The antiozonant ethylene diurea is proven to prevent growth reductions in forest trees induced by ozone. The community of mycorrhizal fungi could be useful indicator of environmental stress. In this study, response of mycorrhizal fungi and fine roots to a 4-year exposure to ambient ozone and treatment with antiozonant was investigated in ozone-sensitive poplar clone under field conditions. The community of ectomycorrhizal fungi and root length colonization with ectomycorrhizal, arbuscular mycorrhizal fungi, and root endophytic fungi was analyzed in antiozonant-treated poplar plants and in poplar plants irrigated with water. In general, plants protected by antiozonant showed higher total number of fine roots, number of ectomycorrhizal types, Shannon–Weaver diversity index, and Species richness index compared to the plants treated with water. The ectomycorrhizal community shifted from contact exploration type in the trees irrigated with water to short-distance exploration type in ethylene diurea-treated trees. Ozone protectant may beneficially affect the belowground community of mycorrhizal fungi colonizing roots of ozone-sensitive poplar clone.

Effects of a three-year exposure to ambient ozone on biomass allocation in poplar using ethylenediurea

We examined the effect of ambient ozone on visible foliar injury, growth and biomass in field-grown poplar cuttings of an Oxford clone sensitive to ozone (Populus maximoviczii Henry × berolinensis Dippel) irrigated with ethylenediurea (EDU) or water for three years. EDU is used as an ozone protectant for plants. Protective effects of EDU on ozone visible injury were found. As a result, poplar trees grown under EDU treatment increased leaves, lateral branches and root density in the third year, although no significant enhancement of stem height and diameter was found. Ambient ozone (AOT40, 24.6 ppm h; diurnal hourly average, 40.3 ppb) may finally reduce carbon gain by reducing the number of branches, and thus sites for leaf formation, in ozone-sensitive poplar trees under not-limiting conditions.

Whole-tree water use efficiency is decreased by ambient ozone and not affected by O3-induced stomatal sluggishness.

Steady-state and dynamic gas exchange responses to ozone visible injury were investigated in an ozone-sensitive poplar clone under field conditions. The results were translated into whole tree water loss and carbon assimilation by comparing trees exposed to ambient ozone and trees treated with the ozone-protectant ethylenediurea (EDU). Steady-state stomatal conductance and photosynthesis linearly decreased with increasing ozone visible injury. Dynamic responses simulated by severing of a leaf revealed that stomatal sluggishness increased until a threshold of 5% injury and was then fairly constant. Sluggishness resulted from longer time to respond to the closing signal and slower rate of closing. Changes in photosynthesis were driven by the dynamics of stomata. Whole-tree carbon assimilation and water loss were lower in trees exposed to ambient O3 than in trees protected by EDU, both under steady-state and dynamic conditions. Although stomatal sluggishness is expected to increase water loss, lower stomatal conductance and premature leaf shedding of injured leaves aggravated O3 effects on whole tree carbon gain, while compensating for water loss. On average, WUE of trees exposed to ambient ozone was 2–4% lower than that of EDU-protected control trees in September and 6–8% lower in October.

Solar UV‐B effects on PSII performance in Betula nana are influenced by PAR level and reduced by EDU: results of a 3‐year experiment in the High Arctic

The long-term and diurnal responses of photosystem II (PSII) performance to near-ambient UV-B radiation were investigated in High Arctic Betula nana. We conducted an UV exclusion experiment with five replicated blocks consisting of open control (no filter), photosynthetic active radiation and UV-B transparent filter control (Teflon), UV-B-absorbing filter (Mylar) and UV-AB-absorbing filter (Lexan). Ethylenediurea (EDU), a chemical normally used to protect plants against ozone injury, was sprayed on the leaves both in the field and in an additional laboratory study to investigate if EDU mitigated the effects of UV-B. Chlorophyll-a fluorescence induction curves were used for analysis of OJIP test parameters. Near-ambient UV-B radiation reduced across season maximum quantum yield (TR(o) /ABS = F(v) /F(m)), approximated number of active PSII reaction center (RC/ABS) and the performance index (PI(ABS)), despite improved leaf screening against UV-B with higher content of UV-B-absorbing compounds and a lower specific leaf area. EDU application counteracted the negative impact of UV-B on TR(o) /ABS, RC/ABS and PI(ABS) . This indicates that the mechanisms behind UV-B and ozone damage share some common features. The midday depression was present in all treatments, but TR(o) /ABS and PI(ABS) were persistently lower in near-ambient UV-B compared to UV-B reduction. The recovery phase was particularly impaired in near-ambient UV-B and interactive effects between treatment × hour raised TR(o) /ABS, RC/ABS and PI(ABS) higher in reduced UV-B compared to near-ambient UV-B. This demonstrates current solar UV-B to reduce the PSII performance both on a daily as well as a seasonal basis in this High Arctic species.

Ambient ozone and two black gram cultivars: an assessment of amelioration by the use of ethylenediurea

Ethylenediurea (EDU) was applied as soil drench in two Indian cultivars of black gram (Vigna mungo L. cv. Azad-1 and BHU-1) and its ameliorating effect against ozone (O3) stress was studied on selected growth, physiological, biochemical, and yield characteristics. The study site experienced a high O3 concentration of 41.3–59.9 ppb during the experimental period. It was found that growth parameters showed positive impact on plants treated with EDU and yield attributes were also higher than that of non-EDU-treated ones. Significant increments in ascorbic acid and protein contents were observed in EDU-treated plants as compared to control plants. Lipid peroxidation, however, showed a reverse trend in both the cultivars. Photosynthetic efficiency increased by EDU treatment as depicted by higher values for photosynthetic rate (Ps) and Fv/Fm ratio. EDU-treated plants had more efficient antioxidant enzyme defense system with higher SOD and POX activities. Both the cultivars showed differential response against O3 and cultivar BHU-1 proved to be resistant as compared to Azad-1. This investigation proves the usefulness of EDU as a biomonitoring tool against O3 for the remote areas having higher concentrations of O3 and problem of frequent electricity failure.

Soil drench of ethylenediurea (EDU) protects sensitive trees from ozone injury

Abstract: Ozone (O3) is the air pollutant of major concern for vegetation. Levels in Mediterranean cities may exceed the criteria for vegetation protection. Ozone may induce a number of plant responses, e.g., visible injury on the leaves, that affect the ornamental value of urban forests. Antioxidant application may protect sensitive plants from ozone. The most successful synthetic antioxidant is ethylenediurea (EDU). Here we set the optimal EDU dose and concentration (260 mg m-2 leaf, 450 ppm) for protecting adult Fraxinus excelsior trees from ozone visible injury by means of EDU applications as soil drench.

Assessing the Impact of Ambient Ozone on Growth and Yield of Crop at Rampur, Chitwan

An experiment was conducted at Institute of Agriculture and Animal Science, Rampur, Chitwan, Nepal during March-July 2008 to explore the impact of ambient ozone on crop growth and yield. Mungbean cultivar "Pratikshya" was used as a test crop for the study. Mungbean plants were planted in 40 pots and 50% of the plants (i.e. plants in 20 pots) were treated with ethylenediurea (EDU) from 13 DAS to crop maturity at 10 days intervals. The ambient ozone level of the site was measured with passive samplers. The ozone level ranged from 29.3 to 39.1 ppb at the experimentation site during the cropping period. It was found that the ambient ozone at the site caused significant effects on plant growth and yield. The observed ambient ozone was found to reduce the growth parameters like plant height, per plant number of leaves, and number of branches by 10%, 27.74%, and 10.88%, respectively at 70 DAS while it reduced per plant number of seeds (13.17%), seed dry weights (19.67%), test weight (g/1000 seeds), (10.28%), total above-ground biomass (16.60%), harvest index (6.25%), and shelling percentage (5.07%) of controlled over EDU treated plants (ozone protected). The study clearly indicated that ambient ozone contributes to lower plant growth and crop yield.Key words: Ambient ozone; Ethylenediurea (EDU); Passive samplerThe Journal of AGRICULTURE AND ENVIRONMENT Vol. 11, 2010Page: 40-45Uploaded Date: 15 Septembre, 2010

Protection of plants from ambient ozone by applications of ethylenediurea (EDU): A meta-analytic review

A meta-analysis was conducted to quantitatively assess the effects of ethylenediurea (EDU) on ozone (O 3) injury, growth, physiology and productivity of plants grown in ambient air conditions. Results indicated that EDU significantly reduced O 3-caused visible injury by 76%, and increased photosynthetic rate by 8%, above-ground biomass by 7% and crop yield by 15% in comparison with non-EDU treated plants, suggesting that ozone reduces growth and yield under current ambient conditions. EDU significantly ameliorated the biomass and yield of crops and grasses, but had no significant effect on tree growth with an exception of stem diameter. EDU applied as a soil drench at a concentration of 200–400 mg/L has the highest positive effect on crops grown in the field. Long-term research on full-grown tree species is needed. In conclusion, EDU is a powerful tool for assessing effects of ambient [O 3] on vegetation.

Cultivar-Specific Response of Soybean (Glycine max L.) to Ambient and Elevated Concentrations of Ozone Under Open Top Chambers

Two cultivars of soybean (Pusa 9814 and Pusa 9712) were investigated to evaluate the impact of ambient and elevated concentrations of ozone (O3) in a suburban site of India with and without application of 400 ppm ethylenediurea (EDU) in open top chambers having filtered air (FCs), non-filtered air (NFCs), and non-filtered plus 20 ppb O3 (NFCs + 20 ppb). Significant reductions were observed in various growth parameters, biomass accumulation, and yield attributes of soybean cultivars due to ambient O3 in NFCs and elevated concentration of O3 in NFCs + 20 ppb. Reductions in all parameters were of lower magnitude in plants treated with EDU as compared to non-EDU treated plants. Yield (weight of seeds plant−1) increased by 29.8% and 33% in Pusa 9712 and by 28.2% and 29.0% in Pusa 9814 due to EDU treatment in plants grown at ambient and elevated levels of O3, respectively. The results clearly showed that (a) EDU can be effectively used to assess phytotoxicity of O3 by providing protection against its deleterious effects, (b) EDU can be used for biomonitoring of O3 in areas experiencing its higher concentrations, and (3) EDU is more effective against higher concentrations of O3.

Responses of two cultivars of Trifolium repens L. to ethylene diurea in relation to ambient ozone

Three ethylene diurea (EDU) concentrations (0, 150 and 300 mg/L) were used to evaluate the negative impact of ozone (O 3)on two cultivars of Trifolium repens L. cv. Vardan and Bundel grown under natural field conditions in a suburban area of Varanasi, India. Mean O 3 concentrations varied from 30.3 to 46.6 μg/L during the experimental period. Higher photosynthetic pigments and ascorbic acid concentrations were noticed in both EDU-treated cultivars over non-EDU-treated ones, but a reverse trend was found for lipid peroxidation. Growth parameters and biomass also showed increments under EDU treatment of both cultivars. The ratio of variable fluorescence to maximum fluorescence increased significantly in Vardan but not in Bundel upon EDU treatment. Results revealed that EDU concentration of 300 mg/L was more effective to combat the oxidative stress as well as protecting plants from O 3 injury symptoms. The test cultivar Vardan is relatively sensitive to O 3, thereby can be used as a bioindicator of O 3 pollution in areas having higher O 3 concentrations. Results also indicated that Bundel has more efficient antioxidant defense system than Vardan and hence was more tolerant to O 3 stress.