Sunflower seedlings subjected to increasing water deficit stress: oxidative stress and defence mechanisms

Sgherri, Cristina; Navari-Izzo, F.

doi:10.1034/j.1399-3054.1995.930105.x

Cited by 170 publications

(93 citation statements)

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“…The importance of NADPH is, besides in the photosynthetic process, as a reducing agent in the regeneration of antioxidants AsA and GSH through the AsA/GSH cycle (9). The increases in the AsA/DHA ratio ( Table 3) and tocopherol contents ( Table 5) with salt treatment in cv.…”

Section: Discussionmentioning

confidence: 99%

“…Thus, the antioxidant activity is important for assessing the nutritional value of fruits and vegetables (8). Because it is well-recognized that the role of antioxidant molecules is critical in the detoxification of free radicals (9), mild salt treatment and fruit ripeness may significantly improve the beneficial nutritional properties of tomatoes and need to be investigated in order to cultivate cultivars with better nutritional characteristics under salinity conditions.…”

Section: Introductionmentioning

confidence: 99%

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The Influence of Diluted Seawater and Ripening Stage on the Content of Antioxidants in Fruits of Different Tomato Genotypes

Sgherri

Navari-Izzo

Pardossi

et al. 2007

J. Agric. Food Chem.

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The aim of this study was to investigate if the combined effect of diluted seawater and ripening can improve the beneficial nutritional properties of tomato fruits from an antioxidant point of view. To reach the goal, different tomato cultivars and breeding lines, genetically modified for ripening, were investigated, and analysis of NADPH and NADP + as well as of the main antioxidants such as ascorbic acid, lipoic acid, and tocopherols was performed at two ripening stages. The research was conducted on berries of the following genotypes of tomato: cv. Jama, Gimar wild type, Gimar gf, and Gimar nor. The mutant gf is a typical "stay green" mutant, characterized by an incomplete loss of chlorophyll; the nor mutation is characterized by a reduced biosynthesis of ethylene and carotenoids. Both ripening and salinity induced an oxidative stress, and the sensitivity to salt treatment was genotype-dependent. The genotypes cv. Jama and Gimar gf line showed increases in ascorbic acid, lipoic acid, and R-tocopherol during both ripening and salt treatment whereas total ascorbate and tocopherols decreased in the berries from salt-treated plants of Gimar wild type. Ripening also determined decreases in ascorbate and tocopherol amounts in the Gimar nor line where a positive effect of ripening and salinity was observed.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The Influence of Diluted Seawater and Ripening Stage on the Content of Antioxidants in Fruits of Different Tomato Genotypes

Sgherri

Navari-Izzo

Pardossi

et al. 2007

J. Agric. Food Chem.

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show abstract

“…This clearly indicates that the induced GR activity in severely salt-stressed plants was insufficient to maintain the glutathione pool in its reduced form, and suggests that glutathione synthesis could be restricted by higher NaCl concentrations when plant growth was reduced by about 70%. It is clear that GSSG accumulation (Sgherri & Navari-Izzo, 1995) and protein-glutathione mixed disulphides increase in plants which are subjected to drought (Kranner & Grill, 1996). The importance of maintaining sufficient GSH pools to support the growth of NaCl-tolerant cell lines has been reported (Gosset et al, 1996).…”

Section:   mentioning

confidence: 99%

Response of antioxidant systems and leaf water relations to NaCl stress in pea plants

et al. 1999

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A pea (Pisum sativum cv. Puget) cultivar was grown on a medium containing different NaCl concentrations (0-160 mol m −$ ) in order to study the effects of salt stress on leaf water relations and on the activity of antioxidant enzymes. NaCl stress caused a rapid decline in chlorophyll content. Both leaf water (ψ l ) and osmotic potentials (ψ s ) decreased progressively with the severity of the stress (from 90-160 mol m −$ NaCl) whereas leaf turgor pressure (ψ p ) increased in treated plants. Pea leaves contained an iron-containing superoxide dismutase (Fe-SOD) isozyme in chloroplasts alongside a copper-zinc-containing (CuZn-SOD) form (CuZn-SOD II). The lowest NaCl concentration (70 mol m −$ ) had no effect on the activity of these antioxidant enzymes while higher concentrations (110-130 mol m −$ ) enhanced the activity of cytosolic CuZn-SOD I and chloroplastic CuZn-SOD II as well as that of mitochondrial and\or peroxisomal manganese-containing superoxide dismutase (Mn-SOD). These inductions were matched by increases in the activity of ascorbate peroxidase (APX) and monodehydroascorbate reductase (MDHAR). The increased activities coincided with decreased stomatal conductance and were unaffected by the severity of stress except in the case of CuZn-SOD II which fell to control values under the highest stress conditions (140-160 mol m −$ NaCl), when a concomitant increase in chloroplastic Fe-SOD activity was observed. Glutathione reductase (GR) and dehydroascorbate reductase (DHAR) activities were only induced under severe NaCl stress (130-160 mol m −$ ) and were accompanied by losses in the ascorbate and glutathione pools, lower ASC\DHA and GSH\GSSG ratios and increases in GSSG. Electron microscopy showed that the thylakoidal structure of the chloroplasts became disorganized and their starch content decreased in plants treated with 160 mol m −$ NaCl. Overall, the results suggest that salt stress is accompanied by oxidative stress, perhaps at the cell compartment level. The capacity of Puget cultivar to ensure cell turgor and to enhance the activity of enzymes involved in the defence against oxidative stress seems to be important in determining adaptation to moderate NaCl stress conditions. In plants exposed to severe NaCl stress (130-160 mol m −$ ) it seems that such resistance to oxidative stress is overcome, which might contribute to the deleterious effects of salt and significant growth reduction in these conditions.

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“…This antioxidant can react with singlet oxygen, superoxide and hydroxyl radicals and thus functions directly as a free radical scavenger (Mckersie and Leshen 1994). Some studies have observed that the glutathione content increased in water-stressed sunflower plants (Sgherri and Navari-Izzo 1995) and in cell lines of salt-stressed groundnut ( Jain et al 2002).…”

Section: Introductionmentioning

confidence: 99%

Enhanced salt tolerance in maize plants induced by H2O2 leaf spraying is associated with improved gas exchange rather than with non-enzymatic antioxidant system

Gondim

Miranda

Prisco

2013

Theor. Exp. Plant Physiol.

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ABSTRACT:Hydrogen peroxide (H 2 O 2 ) is an essential signaling molecule that mediates plant responses against several biotic and abiotic stresses. H 2 O 2 pretreatment has emerged as a signaling way, inducing salt stress acclimation in plants. Here, we analyzed the effects of H 2 O 2 leaf pretreatment on the non-enzymatic defense system (ascorbate and glutathione), plant growth, relative water content (RWC), relative chlorophyll content, H 2 O 2 content, and gas exchange in maize plants under NaCl stress. The results showed that salinity reduced the leaf area and shoot and root dry mass as compared to control, and the leaf spraying with H 2 O 2 significantly improved the growth of salt stressed plants. Photosynthesis and transpiration, stomatal conductance and intercellular CO 2 concentration were strongly decreased by salinity after 7 and 14 days of salt exposure; however, the decrease was lower in plants sprayed with H 2 O 2 . The improved gas exchange in H 2 O 2 -sprayed stressed plants correlated positively with higher RWC and relative chlorophyll content and lower leaf H 2 O 2 accumulation under NaCl stress conditions. Ascorbate and glutathione did not play any obvious effects as non-enzymatic antioxidants in the ROS scavenging. In conclusion, the salt tolerance induced by H 2 O 2 leaf pretreatment is attributed to a reduction in the H 2 O 2 content and maintenance of RWC and chlorophyll in maize leaves. These characteristics allow maize plants to maintain high rates of

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Sunflower seedlings subjected to increasing water deficit stress: oxidative stress and defence mechanisms

Cited by 170 publications

References 0 publications

The Influence of Diluted Seawater and Ripening Stage on the Content of Antioxidants in Fruits of Different Tomato Genotypes

The Influence of Diluted Seawater and Ripening Stage on the Content of Antioxidants in Fruits of Different Tomato Genotypes

Response of antioxidant systems and leaf water relations to NaCl stress in pea plants

Enhanced salt tolerance in maize plants induced by H2O2 leaf spraying is associated with improved gas exchange rather than with non-enzymatic antioxidant system

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