Lead toxicity induces lipid peroxidation and alters the activities of antioxidant enzymes in growing rice plants (original) (raw)
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2010
The amplitude of antioxidative enzymatic response was investigated in Triticum aestivum cv. Maruca. Pb 2+ was provided as solutions of lead acetate [Pb(C 2 H 3 O 2 ) 2 .3H 2 O] and lead nitrate [Pb(NO 3 ) 2 ], at four concentrations (10, 25, 50, 100 µM) containing 2.07, 5.18, 10.36, respectively 20.72 µg ml -1 Pb 2+ . The results support idea that mainly superoxide dismutase and peroxidase are involved in the defence mechanism of wheat seedlings against Pb 2+ toxicity, by scavenging reactive oxygen species. All Pb 2+ concentrations enhanced SOD activity (the increase rates range between 24.59%-65.19%, for Pb 2+ acetate, and between 20.88%-175.40%, for Pb 2+ nitrate treated variants, comparatively to control). Pb 2+ induced the decline of soluble protein level in all variants, indifferently of compound type and lead concentration. Akinci, I.E, Akinci, S., Yilmaz, K., (2010): Response of tomato (Solanum lycopersicum L.) to lead toxicity: Growth, element uptake, chlorophyll and water content. Afr. J. Agric. Res., 5(6), 416-423. Artenie, V., Ungureanu, E., Negură, A.M., (2008): Medode de investigare a metabolismului glucidic si lipidic, Editura Pin, Iaúi. Azmat, R., Haider, S., (2007): Pb stress phytochemistry of seedlings of Phaseolus vulgaris and Lens culinaris. Asian J. Plant Sci, 6(2), 332-337. Babior, B., (1997): Superoxide: a two-edged sword. Braz. J. Med. Biol. Res., 30(2), 141-145. Bradford, M.M., (1976): A rapid and sensitive method for the quantitation of microgram quantities of protein utilising the principle of protein-dye binding. Anal. Biochem., 72, 248-254. Chakravarty, B., Srivastava, S., (1992): Toxicity of some heavy metals in vivo and in vitro in Helianthus annuus. Mutat. Res., 283(4), 287-294. Davies, M.J., (2003): Singlet oxygen-mediated damage to proteins and its consequences. Biochem. Bioph. Res. Co., 305, 761-770. Dey, S.K., Dey, J., Patra, S., Pothal, D., (2007): Changes in the antioxidative enzyme activities and lipid peroxidation in wheat seedlings exposed to cadmium and lead stress. Braz. J. Plant Physiol., 19(1), 53-60. Fatima, R.A., Ahmad, M., (2005): Certain antioxidant enzymes of Allium cepa as biomarkers for the detection of toxic heavy metals in wastewater. Sci Total Environ., 346, 256-273. Fayiga, A., Mo, L., Cao, X., Rathinasabapathi, B., (2004): Effects of heavy metals on growth and arsenic accumulation in the arsenic hyperaccumulator Pteris vittata L. Environ. Pollut., 132, 289-296.
Agronomy, 2021
Lead (Pb) is one of the major environmental heavy metal pollutants, known as being neither essential nor beneficial for any living organisms, and which is detrimental to plant fitness, growth, and productivity, as well as human health. This study investigated the changes in the morphological, physiological, and biochemical properties of rice cultivars exposed to lead (Pb). Therefore, soil was contaminated with a solution containing 0.6 mM or 1.2 mM Pb four weeks prior to transplanting. Then, 4-week-old rice seedlings of Tunnae, Ilmi, Yasmen, Mashkab, and Amber Barka were transplanted into the contaminated soil and grown until maturity. The results showed that a high concentration of lead (1.2 mM) induced significant reduction in the plant height, number of tillers, number of panicles per plant, and the number of spikelets per panicle in Pb-sensitive rice cultivars, while in Pb-tolerant cultivars, a balanced growth of plants and non-significant change in the major yield components we...
Response of Antioxidant Enzymes ,in Rice (Ory7.a sativa L. cv.
We studied the effects of different co~[et~bral~ns of mercury (0.0 to 100 !~t) o. growth and p~Uc efficiency in rice plants treated for 21 d. In addilJo., we invesl~ated how this metal affected Ihe malondtaidehy~ (MDA) content as well as lhe ~ of five ~ enzymes -superoxJde dimnutase (SOD), ascorbale peroxidase (APX), glutathione reductase (GR), guaiacol pemxidase (POD), and ratalase (CAT). ~c ef@~mcy (F,/Fm) and seedling growth decreased as the cancentrabon of H s was increased in the growth media. Plants also responded to Hg-induced oxidaslbress by charting the levels of their antioxiclat~ enzymes. Enhanced lipid peroxidabon was observed in both leaves and roots that had been exposed to oxldal@e m, with leaves showing higher enzymatic acth~. Both SOD and APX acti@l~s increased in beabnents with up to 50 pM I~, then decreased at higher concentrations. In the leaves, bolh CAT and POD acth~es increased ~radually, with CAT levels decreasing at h~her concentratJon~ In the roots, hm~mver, CAT aclivity remained Ui~-hansed while that of POD increased a bit more than did the control for concen~alJons of up to 10 pM H& At higher Hg levels, beth CAT and POD activities decreased. GR act~ increased in leaves exposed to no more than 0.25 pM Hg, then decreased gradually. In contrast, its activity was greatly inhibited in the roots. Based on these results, we surest that when rice plants are exposed to different concentrations of mercury, their anlJoxidative enzymes become involved in defense mechanisms against the free radicals that are induced by this stress.
Agricultural Sciences, 2015
Lead (Pb) is an important environmental pollutant extremely toxic to plants and other living organisms including humans. To assess Pb phytotoxicity, a pot culture experiment was carried out using two groundnut cultivars (Arachis hypogaea L. cultivar K6 and cultivar K9) on plant growth, ROS levels, lipid peroxidation, and antioxidant metabolism using biochemical, histochemical methods. Plants were grown in pots for 14 days, in the botanic garden, and subjected to Pb-stress (0, 100, 200, 400 and 800 ppm) by adding Pb (NO3)2 solution and further allowed to grow for 10 days. The results showed that cultivar K6 registered lower Pb accumulation than cultivar K9, however, localization of Pb was greater in roots than leaves in both groundnut cultivars. The Pb-stress results in an increase in free radicals (O2 • − and H2O2) generation in both groundnut cultivars, but more significantly in cultivar K9 than K6. Pb-stress also caused significant changes in the rate of peroxidation as shown in the levels of malondialdehyde (MDA) content in roots and leaves of both groundnut cultivars. Free proline, ascorbic acid (AsA) and non-protein thiol (NP-SH) contents were increased in cultivar K6 due to Pb-stress, but less in cultivar K9. Pb treated plants showed increased levels of antioxidant enzymes such as superoxide dismutase (SOD), guaiacol peroxidase (GPX), ascorbate peroxidase (APX) glutathione reductase (GR) and glutathione Stransferase (GST). Isozyme band intensities of SOD, GPX and APX were more consistent with the respective changes in antioxidative enzyme activities. These results indicate that cultivar K6 possesses greater tolerance potential for Pb toxicity than cultivar K9.
Forty days old radish plants (Raphanus sativus L.) were exposed to different regimes of lead stress as Pb(NO 3) 2 at the following concentrations 0, 25, 50, 100, 150, 250 and 500 ppm. The possible generation of oxidative stress, antioxidant metabolism and changes in the chloroplast and cell membrane ultrastructure were investigated. Greater loss of the photosynthetic pigments (Chl. a, Chl. b and total carotenoids) were observed especially under 500 ppm lead (Pb). The accumulation of lead in roots and leaves of plant were measured and the results showed that lead accumulation increased with increasing of the metal treatment concentration. An increasing trend was observed in levels of ascorbate and decreasing trend in glutathione. Also, the antioxidant enzymes, viz., guaiacol peroxidase (GPX) ascorbate peroxidase (APX), catalase (CAT) and glutathione S-transferase (GST) showed significant variation with the increase in lead stress compared to control (untreated) plants. The rapid inducibility of some of these enzymes is useful early and sensitive indicators of heavy metal toxicity. Native polyacrylamide gel electrophoresis revealed an increase in the isoenzymes profile of CAT in both leaves and roots. While POD isoenzymes bands prominently increased in leaves and slightly decreased in roots at the higher Pb concentration in the growth media. The ultrastructural studies at selected concentrations; 100 and 500 ppm of Pb showed distortion of the structure and cell membranes in roots. Therefore, the changes in the levels of some antioxidants may play an important role against oxidative injury.
Journal of Stress Physiology & Biochemistry, 2013
2+ was much higher in roots than in shoots, its level rising with increasing pH from 3.0 to 8.0. Not only that, an oxidative stress conditions were observed due to increased level of superoxide anion radical and hydrogen peroxide in shoots and root cells of 20 days old seedlings when treated with Pb(NO 3 ) 2 at a concentration of 0, 500, 1000 and 2000 μM. Spectrometric assays of seedlings showed increased level of activities of antioxidant enzymes like catalase, peroxidase and glutathione reductase. The presence of thiobarbituric acid reacting substances (TBARS) indicates the enhanced lipid peroxidation compared to controls. The alteration in the activities of the antioxidant enzymes and the induction of lipid peroxidation reflects the presence of Pb 2+ , which may cause oxidative stress.
Acta Physiologiae Plantarum, 2009
The lead absorbed by the roots induce oxidative stress conditions through the Reactive oxygen species (ROS) production for the pea plants cultivated hydroponically for 96 h on a Hoagland medium with the addition of 0.1 and 0.5 mM of Pb(NO 3 ) 2 . The alterations in O ÀÁ 2 and H 2 O 2 concentrations were monitored spectrophotometrically which show a rapid increase in O ÀÁ 2 production during the initial 2 h, and in case of H 2 O 2 , during the eighth hour of cultivation. The level of ROS remained higher at all the time points for the roots of the plants cultivated with Pb 2? and it was proportional to metal concentration. The production of O ÀÁ 2 and H 2 O 2 was visualized by means of fluorescence microscope technique. They are produced in nonenzymatic membrane lipid peroxidation and its final product is Malondialdehyde, the level of which increased together with the level of H 2 O 2 . As stress intensity raised (duration of treatment and Pb 2? concentration), so did the activities of superoxide dismutases, catalase and ascorbate peroxidase antioxidative enzymes and of low-molecular antioxidants, particularly glutathione (GSH), homoglutathione (h-GSH) and cysteine substrate toward their synthesis. The root cells redox state (GSH/GSSG) dropped proportionally to lead stress intensity.
Journal of Plant Physiology, 2012
Hydrogen peroxide (H 2 O 2) is considered a signal molecule inducing cellular stress. Both heat shock (HS) and Cd can increase H 2 O 2 content. We investigated the involvement of H 2 O 2 in HS-and Cd-mediated changes in the expression of ascorbate peroxidase (APX) and glutathione reductase (GR) in leaves of rice seedlings. HS treatment increased the content of H 2 O 2 before it increased activities of APX and GR in rice leaves. Moreover, HS-induced H 2 O 2 production and APX and GR activities could be counteracted by the NADPH oxidase inhibitors dipehenylene iodonium (DPI) and imidazole (IMD). HS-induced OsAPX2 gene expression was associated with HS-induced APX activity but was not regulated by H 2 O 2. Cd-increased H 2 O 2 content and APX and GR activities were lower with than without HS. Cd did not increase the expression of OsAPX and OsGR without HS treatment. Cd increased H 2 O 2 content by Cd before it increased APX and GR activities without HS. Treatment with DPI and IMD effectively inhibited Cd-induced H 2 O 2 production and APX and GR activities. Moreover, the effects of DPI and IMD could be rescued with H 2 O 2 treatment. H 2 O 2 may be involved in the regulation of HS-and Cd-increased APX and GR activities in leaves of rice seedlings.
Cadmium-induced changes in antioxidant enzyme activities in rice (Oryza sativa L. cv. Dongjin)
Journal of Plant Biology, 2002
We studied how the relationship between cadmium (Cd) toxicity and oxidative stress influenced the Brm~th, photo.. synthetic efficiency, lipid peroxidation, and activity of ntimddative enzymes in the roots and leaves of rice (Oryza sat/va L Don~in). Plants were exposed to Cd for 21 d. Both seedling growth and photosynthetic efficiency decreased 8radually with increasin 8 cadmium concentrations. Upid peroxi~ increased slowly in both roots and leaves, causing oxidative stress. However, each tissue type responded differentJy to Cd concentrations with regard to the induction/ inhibition of antioxidative enzymes. The acti~/of superoxide dismutase (SOD) increased in both roots and leaves. Ascorbate peroxidase (APX) activity increased in leaves treated with up to 0~5 I~l Cd, then decreased 8radually at higher concentrations. In contrast, APX activity in roots increased and remained constant between 0.25 and 25 pM Cd. Enhanced peroxidase (POD) activity was recorded for treatments with up to 25 ~ Cd, 8radually decreasing at higher concentrations in the leaves but remaining unchan~d in the roots. Catalase (CAT) activity increased in the roots, but decreased in the leaves, whereas the activity of 81utathione reductase (GR) was enhanced in both roots and leaves, where it remained elevated at higher Cd concentrations. These results susBest that.rice seedlinss tend to cope with free radicals bqmerated by Cd throush coordinated, enhanced activities of the antioxidative enzymes involved in detoxification.