Physiological and biochemical responses of cowpea (Vigna unguiculata (L.) Walp) to ozone (original) (raw)
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Plants (Basel, Switzerland), 2017
The interactive effects of drought and ozone on the physiology and leaf membrane lipid content, composition and metabolism of cowpea (Vigna unguiculata (L.) Walp.) were investigated in two cultivars (EPACE-1 and IT83-D) grown under controlled conditions. The drought treatment (three-week water deprivation) did not cause leaf injury but restricted growth through stomatal closure. In contrast, the short-term ozone treatment (130 ppb 12 h daily during 14 day) had a limited impact at the whole-plant level but caused leaf injury, hydrogen peroxide accumulation and galactolipid degradation. These effects were stronger in the IT83-D cultivar, which also showed specific ozone responses such as a higher digalactosyl-diacylglycerol (DGDG):monogalactosyldiacylglycerol (MGDG) ratio and the coordinated up-regulation of DGDG synthase (VuDGD2) and ω-3 fatty acid desaturase 8 (VuFAD8) genes, suggesting that membrane remodeling occurred under ozone stress in the sensitive cultivar. When stresses wer...
Protoplasma, 2014
Surface-level ozone (O3) has been regarded as one of the most significant phytotoxic pollutants worldwide. Investigations addressing adverse impacts of elevated O3 on mung bean (Vigna radiata L.), an important leguminous crop of the Indian subcontinent, are still limited. The present study analyzed the differences on the foliar injury, reactive oxygen species (ROS) generation, antioxidative defense system, physiology, and foliar protein profile of two tropical mung bean cultivars (HUM-2 and HUM-6) exposed to elevated O3 under near-natural conditions. Both cultivars were negatively affected by the pollutant, but the response was cultivar-specific. Results revealed that elevated O3 induced higher levels of ROS (O2·− and H2O2) and lipid peroxidation leading to greater foliar injury in HUM-2 compared to HUM-6. Photosynthetic pigments, photosynthetic rate, stomatal conductance, and photochemical efficiency reduced under elevated O3 exposure and the extent of reduction was higher in HUM-2. Principal component analysis revealed that photosynthetic performance and quantum yield were drastically affected in HUM-2 as compared to HUM-6. Activities of antioxidative enzymes were also stimulated, suggesting generation of oxidative stress under elevated O3. HUM-6 showed higher induction of antioxidative enzymes than HUM-2. One-dimensional gel electrophoresis analysis showed drastic reductions in the abundantly present ribulose-1,5-bisphosphate carboxylase/ oxygenase (RuBisCO) large and small subunits and the decrease was higher in HUM-2. Altogether, results suggested that higher accumulation of ROS and limited induction of antioxidant defense system led to more leaf injury and impairment of photosynthesis in HUM-2 than HUM-6 depicting its higher sensitivity towards elevated O3
Plant susceptibility to ozone: A tower of Babel?
Science of The Total Environment, 2019
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Tropospheric ozone is one of the most important constituent of photochemical smog. In Hungary, the bioindication of ozone has started in June 2007, using the ozone bioindicator clover clones (Trifolium repens NC-S and NC-R) and bean strains (Phaseolus vulgaris S156 and R123) according to the ICP Vegetation Protocol. Besides collecting ozone and meteorological data, ozone injuries, dry weight and number of flowers of clover plants, and dry weight and number of pods of bean clones were assessed. Stomatal conductance and chlorophyll fluorescence of experimental plants were also measured. The typical symptoms of ozone injury were observed on sensitive clones of both plant species, and the extent of symptoms proved to be directly proportional to the ozone pollution expressed as the cumulative daily AOT40 values. Besides the typical symptoms, number of flowers of clover clones could also be a useful indicator of tropospheric ozone load. In addition, the measured physiological parameters s...
TheScientificWorldJournal, 2007
Plant strategies to survive ozone stress include exclusion or tolerance of ozone. If these processes fail, past observations of ozone injury have indicated many physiological and metabolic changes then occur; most of these changes are likely to have been initiated at the level of gene expression, suggesting signal transduction. In the last decade considerable understanding of the biochemical process within plants has been developed. Currently there are several hypotheses regarding a response of plants to ozone fumigation: [1] membrane dysfunction and alteration of purpose; [2] stress ethylene interactions; [3] impairment of photosynthesis via changes in Rubisco levels and the guard cells so that the stomata do not track correctly the environment; [4] antioxidant protection through metabolites and enzyme systems to reduce the oxidant load; and [5] general impairment or disruption of metabolic pathways. Many believe that free radicals and other oxidative products, formed in plant leav...
Environmental and Experimental Botany, 2006
Physiological and biochemical responses to acute ozone exposure for 29 plants belonging to natural and semi-natural european ecosystems were characterised and used to reveal common features among species. Plants were grown in controlled conditions and exposed to acute ozone fumigation at 150 ppb for 3 h. Parameters of chlorophyll a fluorescence, pigments content and antioxidant enzyme activity were measured in control and ozone-treated plants and the data obtained from these analyses was used to perform multivariate statistics. The results indicated that the treatment with ozone and the species diversity, as well as the interaction between the two factors, were able to significantly affect the variables as a whole. Ozone treatment affected plant metabolism to different extents for the different species, even if the statistical analyses performed proved that most of them could be grouped in two main clusters. The first cluster is mainly affected in the photosynthetic performance, as indicated by the decrease in the F v /F m ratio and the increase in the de-epoxidation index, while the second one grouped species characterised by strong reductions in leaf pigment content and by increases in peroxidase activity. The observation that most of the parameters analysed were differently affected by the treatment in the natural and semi-natural species investigated pointed out that the different constitutive metabolic behaviour could account for a different susceptibility to the pollutant and, as a consequence, for a different performance of some of the species in heavily polluted environments.
Scientia Horticulturae, 2019
Determining plant reactions to atmospheric pollutants is important in predicting and planning for new horticultural production management programs and challenges in the future. A high level of ozone in the troposphere is considered the most phototoxic air pollutant, and has strong oxidative potential. This study aimed to provide understanding on the role of ozone stress on early vegetative growth stage Pak-Choi (Brassica campestris L. ssp. chinensis). An experiment was conducted within airtight bio-chambers under 150 ppb ozone concentration with different exposure durations: control, 1 h/day and 4 h/day. The leaf area was not affected by ozone treatment, but the dry matter correlated negatively with increasing ozone exposure durations. In photopigments, the lutein, lycopene and chlorophylls were increased at 1 h/day exposure, however, total carotenoids and β-carotene were not affected. However, for the 4 h/day exposure condition, all photopigment contents were significantly decreased in comparison to the 1 h/day exposure. The total aliphatic and total glucosinolate (GLS) were significantly increased at 1 h/day exposure, and then significantly decreased at 4 h/day exposure. However, the total indole and aromatic GLS were significantly increased after 4 h/day exposure. Therefore, these results provide evidence about the impact of ozone stress on the specific secondary plant metabolites of Pak-Choi and this needs to be taken in account when selecting urban production sites for vegetables.
Sustainability
Tropospheric ozone is a harmful air pollutant and greenhouse gas that adversely affects living organisms. The effect of long-term ozone stress on the activity of SOD, APX, and GuPX, as well as lipid peroxidation and membrane injury in bean and petunia growing at a city site and in a forest, characterised by different ozone concentrations, was examined. The experiments were conducted in three growing seasons with different tropospheric ozone concentrations and meteorological conditions. Plants’ exposition to increased ozone concentration resulted in enhanced activity of antioxidant enzymes, level of lipid peroxidation, and membrane injury. In all years, higher ozone levels and solar radiation were observed at the forest site. The pattern of the changes in enzyme activity was dependent on ozone concentrations as well as on environmental conditions and varied from year to year. In the second year with the highest ozone concentration, the activity of GuPX and SOD increased the most. How...
Impact of Tropospheric Ozone on Crop Plants
Proceedings of the National Academy of Sciences, India Section B: Biological Sciences, 2012
Tropospheric ozone (O 3 ) is the most important regional atmospheric pollutant causing risk to food production across the globe due to its phytotoxicity and prevalence over agricultural areas. Peak O 3 concentrations have declined in Europe and North America due to reductions in precursors during the last decades, however, emissions of O 3 precursors have increased in Asia. The current critical level of ozone is determined by the threshold for yield loss which is based on the seasonal sum of the external concentration above 40 ppb. In the present article, the impact of tropospheric O 3 on crop photosynthesis, defense mechanism, growth, reproductive processes and yield of crop plants have been documented. O 3 upon its entry into the leaf intercellular spaces rapidly forms reactive oxygen species and reacts with components of the leaf apoplast to initiate a complex set of responses that constitute variable countermeasures by antioxidative enzymes. Ozone affects photosynthetic process by influencing photosynthetic pigments, chlorophyll fluorescence kinetics and electron transport as well as carbon fixation in terms of decreased Rubisco activity and quantity. Translocation and allocation pattern of photosynthate also get influenced under O 3 , which affect reproductive processes and yield of crops. Plant species and cultivars exhibit a range of sensitivity to O 3 , which is identifiable in terms of biochemical, physiological, molecular and yield responses. Hence, understanding of cultivar sensitivity in context to O 3 would be helpful in development of potential O 3 biomarkers and O 3 tolerant variables.