Lipid changes in senescing cucumber cotyledons

Draper, S. R.

doi:10.1016/s0031-9422(00)85948-8

Cited by 67 publications

(17 citation statements)

References 18 publications

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“…Draper also observed that the proportion of 18 : 3 in free fatty acids increased with senescence of cucumber cotyledons, and suggested that the increase might be accounted for by the breakdown of chloroplast lipids, in particular the galactofipids (4).…”

Section: Discussionmentioning

confidence: 98%

Polar Lipids Content and their Fatty Acid Composition with Reference to Yellowing of Stored Spinach Leaves

Yamauchi

Iida

Minamide

et al. 1986

Engei Gakkai zasshi

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SummaryChanges in the content of polar lipids and in their fatty acid composition in spinach leaves during storage were studied in order to clarify the mechanism of leaf-yellowing.The total glycolipids, particularly monogalactosyldiglyceride (MGDG) and digalactosyldiglyceride (DGDG), decreased markedly during storage at 25°C . The total phospholipids, however, decreased moderately during storage at 25°C, the decrease in phosphatidylglycerol (PG) being the most notable.In the chloroplast lipids (MGDG, DGDG and PG), the relative amounts of hexadecatrienoic acid in MGDG, and palmitoleic acid and linolenic acid in PG decreased during storage at 25°C. Conversely, the relative amount of linoleic acid in MGDG, DGDG and PG increased. The percentage of unsaturated fatty acids in all the polar lipids, however, showed hardly any change.From these results, it is inferred that the degradation of chlorophylls may be caused by the hydroperoxides of free fatty acids which have been formed by the degradation of polar lipids such as MGDG , DGDG and PG.

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Section: Discussionmentioning

confidence: 98%

Polar Lipids Content and their Fatty Acid Composition with Reference to Yellowing of Stored Spinach Leaves

Yamauchi

Iida

Minamide

et al. 1986

Engei Gakkai zasshi

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“…Free fatty acids were extracted from the first column fraction with 1% Na2CO3 solution, following the method of Draper (2). Methyl esters of free and previously esterified fatty acids were produced according to Luddy et al (11), using a methanolic base reagent, which was prepared by dissolving 1.45 g metallic potassium in 100 ml anhydrous methanol.…”

Section: Methodsmentioning

confidence: 99%

Membrane Lipids in Senescing Flower Tissue of Ipomoea tricolor

Beutelmann

Kende²

1977

Plant Physiol.

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Rib segments excised from flower buds ofIpomoea tricolor Cav Labelng experiments using 33P as marker showed that the rate at which radioactivity was lost from phospholipids during aging was parallel to the rate at which the level of total phospholipids declined. Exogenously applied ethylene accelerated the loss of phospholipid and the senescence of rib segments while benzyladenine retarded both of these processes.Ag+, which counteracts the effect of ethylene in many plants, inhibited rolling up of the rib segments but did not affect either spontaneous and ethylene-induced ethylene generation, or phospholpid loss.In contrast, Co2+, a purported inhibitor of ethylene synthesis, reduced ethylene production, rolling up, and phosphoUpid loss. The inhibition of ethylene-induced rolling up by Co2+ could not be overcome with exogenous ethylene, however.Our results indicate that phospholipid loss is a marker for membrane degradation in rib segments. Changes in membrane integrity and in cellular compartmentation may be the basis for ethylene synthesis during aging of flower tissue.

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“…This has been demonstrated for senescing carnation flowers (25), senescing rose petals (3), senescing flowers of Ipomoea (1), senescing Tradescantia petals (23), senescing cotyledons of cucumber and bean (6,16) and ripening pepper fruit (15). It has been proposed that the decrease in phospholipids is the result of increased degradation, decreased synthesis, or possibly both (4,23).…”

mentioning

confidence: 98%

Molecular Species Specificity of Phospholipid Breakdown in Microsomal Membranes of Senescing Carnation Flowers

Brown¹,

Lynch²,

Thompson³

1987

Plant Physiol.

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ABSTRACrDuring senescence of cut canation flowers, there is extensive breakdown of microsomal phospholipid. This is attributable, at least in part, to lipolytic activity associated directly with the microsomal membranes. Evidence indicating that one or more of the lipid-degrading enzymes in these membranes preferentially degrade phospholipid molecular species containing two diunsaturated acyl chais or at least one polyunsaturated acyl chain has been obtained by using radiolabeled phosphatidylcholine the lipids more susceptible to attack by lipases.In the present study, we describe evidence indicating that the phospholipid-degrading enzymes associated with microsomal membranes of senescing carnation flowers exhibit specificity for phospholipid molecular species containing two diunsaturated fatty acids or at least one polyunsaturated fatty acid. This finding is discussed in the context that provision of specific molecular species of phospholipids, which serve as preferred substrates for membrane-associated lipases, may regulate the progression and rate of phospholipid degradation in senescing membranes. MATERIALS AND METHODSPlant Material and Membrane Isolation. Carnation flowers (Dianthus caryophyllus L. cv White Sim) were grown in a commercial greenhouse (Unsworth and Sons, Burlington, Ontario). They were cut at a young stage when the petals had expanded approximately 2 cm beyond the sepals. The stems were trimmed to a length of 22 cm, and the flowers were placed individually in glass culture tubes containing deionized water. They were maintained at 22°C under continuous illumination (240 ft-c) until they had reached specific stages of senescence, viz., stage II, flowers that still possessed yellowish-tinted centers, but were fully expanded; stage III, flowers that were completely white in color but were not yet showing petal-inrolling; stage IV, senescent flowers showing petal-inrolling.Microsomal membranes were isolated from stage II, III, and IV flowers in 10 mm Epps3 (pH 8.5), as described previously (25) and washed once by resuspension in the same buffer and centrifugation at 131,000g for 1 h. The resulting pellet of membranes was resuspended in 3 ml 70 mM Epps (pH 8.5), and dialyzed at 4°C against 3 changes of 600 ml of 2 mm Epps (pH 8.5), for 15 h. After dialysis, the protein concentration was adjusted to 1 mg ml-' with 70 mM Epps (pH 8.5). Protein was measured as described by Bradford (5).Phospholipid Degradation. The capability of isolated microsomal membranes to degrade various molecular species of phospholipids was determined by using radiolabeled substrates. An aliquot (1.8 ml) of washed, dialyzed membrane suspension (I mg protein ml-') was vortexed for 3 min with 0.

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Lipid changes in senescing cucumber cotyledons

Cited by 67 publications

References 18 publications

Polar Lipids Content and their Fatty Acid Composition with Reference to Yellowing of Stored Spinach Leaves

Polar Lipids Content and their Fatty Acid Composition with Reference to Yellowing of Stored Spinach Leaves

Membrane Lipids in Senescing Flower Tissue of Ipomoea tricolor

Molecular Species Specificity of Phospholipid Breakdown in Microsomal Membranes of Senescing Carnation Flowers

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