Simulation of the Effects of Leaf Senescence on Membranes by Treatment with Paraquat

Chia, Loo Sar; Thompson, John E.; Dumbroff, E. B.

doi:10.1104/pp.67.3.415

Cited by 63 publications

(30 citation statements)

References 18 publications

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“…It was speculated that the change in their proportion is likely to be correlated with a change in physical properties of organellar membranes (Ben-Rais et al, 1993;Mishra et al, 1998). Besides, many studies have revealed that membranes in mature tissues are in liquid crystalline state, while in senescent tissue the membranes or a portion thereof, are in the crystalline gel phase at physiological temperatures (Lees and Thompson, 1980;Chia et al, 1981). Thus, the membrane phase alteration may be a consequence of qualitative changes in membrane lipids like glycolipids, phospholipids and MGDG/DGDG ratio.…”

Section: Resultsmentioning

confidence: 99%

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Changes in lipid profile during growth and senescence of Catharanthus roseus leaf

Mishra¹,

Tyagi²,

Singh³

et al. 2006

Braz. J. Plant Physiol.

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Various lipid classes and compounds were monitored during the period of leaf emergence to leaf drop of Catharanthus roseus. The expansion to early maturation phase was accompanied by cellular build-up of all major lipid classes, whilst aging and senescence were characterized by their substantial decline, except for the neutral lipids; the leaf monogalactosyl diglyceride/digalactosyl diglyceride ratio decreased from 4.3 (complete maturity) to 2.1 (abscised stage). The early maturation stage was the earliest stage when appreciable amounts of free sterols and fatty acids could be observed. Sterol/phospholipids ratios increased by 68-fold in the abscised leaf as compared to that at full maturity. The unsaturated/saturated fatty acid ratio was far lower in the senescent leaf as compared to that of the fully expanded leaf. The spatial alterations in lipid profiles may be suggestive of concomitant changes in membrane ultrastructure and functions, putatively leading to perturbation of indole alkaloid sequestration capability of the tissues of a species of pharmaceutical significance. Key words: Catharanthus roseus, glycolipids, leaf development, phospholipids, senescence, sterol Alterações no perfil de lipídeos durante o crescimento e a senescência de folhas de Catharanthus roseus: Rastrearamse alterações na composição de vários compostos e classes de lipídeos em folhas de Catharanthus roseus, desde a emergência até a abscisão. Da expansão ao início da maturação da folha, houve incrementos nas concentrações de todas as principais classes de lipídeos, observando-se tendência oposta na senescência, à exceção de lipídeos neutros; a razão monogalactosil diglicerídeo/digalactosil diglicerídeo decresceu de 4.3 (maturidade completa) para 2.1 (abscisão). Quantidades apreciáveis de esteróis e ácidos graxos começaram a ser observadas apenas no início maturação foliar. A razão esteróis/fosofolipídeos aumentou 68 vezes na fase de abscisão em relação à folha em sua completa maturidade. A razão ácidos graxos insaturados/ácidos graxos saturados foi muito menor na folha senescente que na folha jovem completamente expandida. As alterações espaciais no perfil de lipídeos podem ser uma sugestão de alterações concomitantes na função e ultra-estrutura da membrana, acarretando, putativamente, perturbações na capacidade de seqüestro de alcalóides dos tecidos de uma espécie importante, de um ponto de vista farmacêutico.

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Section: Resultsmentioning

confidence: 99%

“…nd = not detected. phospholipids ratio as senescence progresses (Chia et al, 1981;Mishra et al, 1998). In the present study, a 67-fold increase in the sterol/phospholipids ratio was observed for the Catharanthus leaf compared to that of the leaf at full maturity (Table 4).…”

Section: Lipid Profile During Growth and Senescence Of Catharanthus Rmentioning

confidence: 99%

Changes in lipid profile during growth and senescence of Catharanthus roseus leaf

Mishra¹,

Tyagi²,

Singh³

et al. 2006

Braz. J. Plant Physiol.

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“…Peroxidation of membrane lipids appears to be an inherent feature of senescence (7,8,16,22). The reactions of peroxidation can be initiated enzymically through lipoxygenase, and the finding that a proportion of the total lipoxygenase activity in senescing tissues is associated with membranes (16,17) suggests a role for this enzyme in the lipid peroxidation reactions of senescing membranes.…”

Section: Discussionmentioning

confidence: 99%

Membrane Deterioration in Senescing Carnation Flowers

Fobel¹,

Lynch²,

Thompson³

1987

Plant Physiol.

Self Cite

109

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The lipid fluidity of microsomal membranes from the petals of cut carnation flowers decreases as the flowers senesce. A comparable chane in fluidity was induced by in vitro aging of microsomal membranes from youn flowers under conditions in which membranous lipoxygenase-like activity was active. There was no change in fluidity when the membranes were aged in the presence of inhibitors of lipoxygenase or were heatdenatured prior to aging. Membranes from naturally senesced flowers and membranes that had been aged in vitro both sustained an increase in saturated.unsaturated fatty acid ratio that accounted for the decrease in lipid fluidity, and in both i s there was evidence for depletion of the unsaturated fatty acids, linoleic acid, and linolenic acid, which are substrates for lipoxygenase. Loss of lipid phosphate reflecdtng breakdown of membrane phospholipids preceded the depletion of unsaturated fatty acids attributable to the lipoxygenase-like activity. The data have been interpreted as indicating that fatty acid substrates for membrane-associated lipoxygenase-like activity are made available by the initiation of phospholipid degrdation, and that the utilization of these substrates results in a selective depletion of unsaturated fatty adds from the membrane and an ensuing decrease in bulk lipid fluidity.Membrane deterioration attributable to lipid degradation and ensuing destabilization ofthe bilayer appears to be a fundamental feature of senescence (28). During the early stages of senescence, there is a pronounced decline in membrane phospholipid that becomes manifested as an increased membrane sterol:fatty acid ratio (2,19,26 lipid fluidity (1,4,19,26). There are also large changes in the phase properties of senescing membranes that have been attributed to lipid peroxidation (24,27).Lipoxygenase, an enzyme that is capable of forming activated oxygen and initiating lipid peroxidation, is also associated with senescing membranes (16, 17). As senescence progresses, linoleic acid and linolenic acid, which are substrates for lipoxygenase, would be among the fatty acids released from membrane phospholipids. In the present study, we have examined the extent to which membrane deterioration in senescing carnation flowers can be attributed to the concerted effects of phospholipid degradation and the action of membrane-associated lipoxygenase-like activity. Epps3 (pH 8.5), and centrifugation at 131,000g for 1 h. The resulting pellet was suspended in 2 mm Epps (pH 8.5), to a concentration of 2 mg protein ml-' and either used directly or dialyzed. In the latter case, 6 ml of membrane suspension (2 mg protein ml-') were dialyzed against 1,000 ml of 10 mm Epps (pH 8.5), at 5°C. The buffer was changed after 1 and 2 h, and dialysis was then continued for an additional 12 h. MATERIALS AND METHODS PlantFor in vitro aging experiments, the membrane suspension was diluted to 0.1 mg protein ml-' in 2 mM Epps adjusted to pH 7.3 or 8.5, and 60 ml of the diluted suspension were incubated in a 50 ml Erlenmeyer flask at 24°C. ...

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“…Paraquat was used to simulate the ROS-induced damage caused by other environment stresses, such as drought, heat and salinity (Chia et al 1981, Bhatt et al 2011. The development of paraquat-resistant varieties could be an effective strategy to counteract various environmental stresses and ensure high crop yields.…”

Section: Introductionmentioning

confidence: 99%

“…• by up to ten-fold (Chia et al 1981). Paraquat was used to simulate the ROS-induced damage caused by other environment stresses, such as drought, heat and salinity (Chia et al 1981, Bhatt et al 2011.…”

Section: Introductionmentioning

confidence: 99%

Effects of Paraquat-induced oxidative stress on antioxidants and Chlorophyll Fluorescence in stay-green wheat (Triticum aestivum L.) flag leaves

et al. 2014

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Paraquat, a highly toxic herbicide, induces the production of reactive oxygen species in the cell. Paraquat resistance in stay-green wheat (Triticum aestivum L.) was investigated. Two cultivars, CN12 and CN17, were found to have a higher photo-oxidative resistance than that of common wheat MY11, as measured with antioxidant indexes and chlorophyll a fluorescence. The flag leaves of both CN12 and CN17 maintained a relatively high antioxidant enzyme activity, chlorophyll content, and photosynthetic index and a low level of lipid degradation after 24 h of treatment with 10 µM paraquat. The Stay-green wheat cultivars CN12 and CN17 had a high resistance to paraquat-induced photo-oxidative stress, which can potentially alleviate some of the damage induced by environment pollution.

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Simulation of the Effects of Leaf Senescence on Membranes by Treatment with Paraquat

Cited by 63 publications

References 18 publications

Changes in lipid profile during growth and senescence of Catharanthus roseus leaf

Changes in lipid profile during growth and senescence of Catharanthus roseus leaf

Membrane Deterioration in Senescing Carnation Flowers

Effects of Paraquat-induced oxidative stress on antioxidants and Chlorophyll Fluorescence in stay-green wheat (Triticum aestivum L.) flag leaves

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