Studies on Auxin Protectors

Stonier, Tom; Yang, Hsin‐Mei

doi:10.1104/pp.51.2.391

Cited by 48 publications

(10 citation statements)

References 13 publications

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“…Auxins function as senescence retardants in fruit (9) and H202 may be involved in the oxidative breakdown of IAA (21,24). This results in the formation of IAA oxidation products which can promote senescence in fruit (6,11).…”

Section: Resultsmentioning

confidence: 99%

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Involvement of Hydrogen Peroxide in the Regulation of Senescence in Pear

Brennan

Frenkél²

1977

Plant Physiol.

712

339

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Endogenous peroxide levels in pear fruit (Pyrus communis) were measured using a titanium assay method, and were found to increase during senescence in both Bartlett and Bosc varieties. Application of glycolic acid or xanthine, serving as substrates for the formation of H202, increased the peroxide content of the tissue and accelerated the onset of ripening, as measured by increased softening and ethylene evolution. Application of ethylene also induced increased peroxide levels. Ripening processes were similarly promoted when peroxides were conserved by inhibiting the activity of catalase with hydroxylamine or potassium cyanide. By comparison, the inhibition of glycolate oxidase with alphahydroxy-2-pyridinemethanesulfonic add decreased the peroxide content of the tissue and delayed the onset of ripening. These results indicate that the onset of ripening correlates with the peroxide content of fruit tissues as occurring under normal conditions or as influenced by the treatments. Hydrogen peroxide may be involved in oxidative processes required in the initiation and the promotion of ripening.Fruit ripening is viewed as an oxidative phenomenon (3, 5), as indicated by results suggesting the decline in sulfhydryl gradients during ripening (7) and the acceleration of ripening processes by the application of high 02 tensions (2, 5, 10). We hypothesize that the effects of 02 reflect, in part, the utilization of 02 for the formation of peroxides for the following reasons.a. The free radical theory of aging proposes that progressive aging results from the random and cumulative attack by oxygen radicals (partially reduced oxygen forms) (16). However, the view of ripening as a regulated senescence phenomenon (13) requires a controlled turnover of radicals. Hydrogen peroxide is a stable partially reduced oxygen form (15), and its turnover is characteristically mediated by enzyme action. For that reason, we envision that H202 can be integrated into the regulated metabolic events occurring during senescence in fruit.b. The acceleration of ripening by high 02 tensions (6, 10) is consistent with the high Km(02) of some peroxide-forming enzyme systems (26).c. The onset of senescence in some systems is accompanied by an increase in the activity of peroxide-utilizing enzymes (4) and a decrease in peroxide-destroying enzymes (17).In the present work, we found that changes in peroxides, as The treated fruit were kept at 21 C at standard conditions and ventilated with air at a rate of 400 ml/min. Ethylene was scrubbed from the ventilating air with Purafil (H. E. Burrough and Assoc., Chamblee, Ga.).Fruits were sampled at intervals for measuring the rate of softening, ethylene evolution, and peroxide levels. Softening and peroxides were measured at 0, 2, 4, 6, and 8 days following infiltration. Ethylene evolution was measured daily for the duration of the experiment. Samples of 10 fruit were used for each of the above determinations. All determinations were run in duplicate. Ethylene was collected from the ventilating gases accor...

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Section: Resultsmentioning

confidence: 99%

“…Peroxides may oxidize sulfhydryl groups (24) and thereby enhance the onset of ripening (7). Peroxides in combination with superoxides can give rise to hydroxyl radicals and singlet oxygen which may be implicated in aging and senescence processes (1).…”

Section: Resultsmentioning

confidence: 99%

Involvement of Hydrogen Peroxide in the Regulation of Senescence in Pear

Brennan

Frenkél²

1977

Plant Physiol.

712

339

View full text Add to dashboard Cite

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“…In plants, peroxidase either bound to cell wall or located in the protoplast (Mader 1976). Cell wall bound peroxidases are probably involved in lignification while other isoenzymes have the regulatory role in plant senescence or in the destruction of auxins (Frenkel 1972;Stonier and Yang 1973). Due to changed ecological condition isoforms of this stress related enzymes are differentially expressed in different habitats.…”

Section: Research Articlementioning

confidence: 99%

Differential expression of physiological and biochemical characters of some Indian mangroves towards salt tolerance

Nandy

Dasgupta

Das

2009

Physiol Mol Biol Plants

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Mangroves are physiologically interesting as potential models for stress tolerance and as sources of alternative ideas about physiological strategies relevant at the ecosystem level. Variation in habitat has great impact on the physiological behavior and biochemical expression level of a particular plant species. Five species of mangroves, growing in saline and fresh water conditions were assessed for their ecological fitness in two different habitats. Assessments were based on some physiological and biochemical parameters measured from the fully exposed mature leaves under saline (15 -27 PPT) and non-saline (1.2 -2 PPT) conditions. Among the five species considered for investigation Bruguiera gymnorrhiza, Excoecaria agallocha and Phoenix paludosa grow luxuriously in the Sundarbans forest, while the rest two (Heritiera fomes, Xylocarpus granatum) are scanty. A comparative account of photosynthetic efficiency, chlorophyll content, mesophyll and stomatal conductance, specific leaf area, photosynthetic nitrogen use efficiency, total foliar free amino acids and differential expression of some antioxidant isoenzymes in leaf were estimated between the saline and non-saline plants. Elevated assimilation rate coupled with increased chlorophyll content, increased conductance and higher specific leaf area in non-saline condition indicates ability of these mangroves to grow even under minimal substrate salinity. The optimum PAR acquisition for photosynthesis in B. gymnorrhiza, E. agallocha and P. paludosa was higher under salt stress, while the maximum assimilation rate was lower in control plants. The opposite trend occurred in H. fomes and X. granatum, where the peak photosynthesis was lower under non-saline conditions even at a higher irradiance than in the saline forest. The isoform patterns of peroxidase, acid phosphatase and esterase indicated considerable difference in regulation of these enzymes due to salt stress and /or reverse adaptation.

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“…In plants, peroxidase is either bound to cell wall or located in the protoplast (Mader 1976). Cell wall bound peroxidases are probably involved in lignification while other isoenzymes have the regulatory role in plant senescence or in the destruction of auxins (Frenkel 1972;Stonier and Yang 1973). Due to changed ecology, isoforms of these stress-related enzymes were differentially expressed.…”

Section: Introductionmentioning

confidence: 99%

Salinity-imposed changes of some isozymes and total leaf protein expression in five mangroves from two different habitats

Dasgupta

Nandy

Tiwari

et al. 2010

Journal of Plant Interactions

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A comparative account of the polymorphic expression of two antioxidative enzymes (Peroxidase and Superoxide dismutase), two hydrolyzing enzymes (Esterase and Acid phosphatase) and total proteins was estimated both qualitatively and quantitatively from the leaves of five mangroves (Bruguiera gymnorrhiza, Excoecaria agallocha, Heritiera fomes, Phoenix paludosa and Xylocarpus granatum) from two different habitats (in situ habitat of Sundarbans and their replicas from ex situ habitat in fresh water condition) and discussed. The higher amount of total protein occurred in fresh water plants compared to their Sundarbans counterparts. The increment of total protein ranged among 156% to 5.7%. Gel electrophoresis experiments revealed that in most of the cases there were extra numbers of protein bands expressed with relatively low molecular weight in saline habitat. In all salinity imposed plants, there were sharp increases in band intensity and the number of isoforms of investigated enzyme. Peroxidase increment in saline plants ranged from 257Á139%. Similarly, SOD was estimated at 247Á147% in saline habitats. Increments of Esterase and Acid phosphatase varied from 287Á154% and 293Á139%, respectively.

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Studies on Auxin Protectors

Cited by 48 publications

References 13 publications

Involvement of Hydrogen Peroxide in the Regulation of Senescence in Pear

Involvement of Hydrogen Peroxide in the Regulation of Senescence in Pear

Differential expression of physiological and biochemical characters of some Indian mangroves towards salt tolerance

Salinity-imposed changes of some isozymes and total leaf protein expression in five mangroves from two different habitats

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