Toxicity of Anaerobic Metabolites Accumulating in Winter Wheat Seedlings during Ice Encasement

Andrews, Christopher J.; Pomeroy, M. Keith

doi:10.1104/pp.64.1.120

Cited by 48 publications

(37 citation statements)

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“…Metabolites of anaerobic respiration, such as ethanol, CO2, and lactic acid accumulate in tissues of winter cereals during ice encasement (1,4,18,21) and flooding at low temperature (7,19). 02 consumption of tissue segments and mitochondria from ice-encased seedlings declines more slowly than the decline in seedling viability (3,18 'To whom reprint requests should be forwarded.…”

Section: Introductionmentioning

confidence: 99%

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Interactions among Flooding, Freezing, and Ice Encasement in Winter Wheat

Gao¹,

Andrews²,

Pomeroy³

1983

Plant Physiol.

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Exposure of winter wheat ( Triticwn aestivum L.) to various combitions of flooding and freezing stresses induces much greater damage than the individual stresses. Cold-hardened plants flooded for 1 week or exposed to -6°C for 1 week show 100% survival, while survival of plants exposed to both stresses simultaneously is reduced by 20 to 30%, and cold hardiness decreases by several degrees. The level of nonstructural carbohydrates increases in crown tissue during cold acclimation, but decreases when the plants are exposed to flooding or to -6°C for 1 week. The respiratory capacity of crown tissue segments declines when the plants are sbessed. Uptake of MRb by the roots of intact seedlns declines after exposure to either freezing or flooding, whereas passive efflux of amino acids is observed after freezing but not folowing flooding. This study has shown that detectable stress-induced metabolic changes occur in winter wheat before the applied stress is severe enough to reduce survival.The precise nature of overwintering damage to winter cereals is not well understood. Overwintering cereals are frequently exposed to a number of adverse environmental stresses, including subfreezing temperatures, low-temperature flooding, and ice encasement, which singly or in combination may be lethal. In geographical areas where mid-winter temperatures are extremely low and snow cover is sparse, plants may be killed directly by low temperature. In areas where winter rains or unseasonable thaws occur, refreezing of fully hydrated plants may cause severe injury (15). The damaging effect of ice encasement (2, 18) and flooding at low temperature (19) on survival of winter cereals also has been well documented. Recent studies (5), however, have demonstrated that icing tolerance of winter wheat is increased significantly by a flooding pretreatment at low temperature.Exposure of winter cereals to various low-temperature environmental stresses results in major changes in physiological and metabolic processes. Metabolites of anaerobic respiration, such as ethanol, CO2, and lactic acid accumulate in tissues of winter cereals during ice encasement (1,4,18,21) and flooding at low temperature (7,19). 02 consumption of tissue segments and mitochondria from ice-encased seedlings declines more slowly than the decline in seedling viability (3,18 'To whom reprint requests should be forwarded.flooding (19). Membrane permeability to amino acids and salts increases markedly during ice encasement or exposure to CO2 and ethanol at -1°C (4).These studies have greatly increased our knowledge of the effects of individual stresses on physiological and biochemical processes in winter cereals, but little is known about many of the interactions among these stresses. This paper reports the effect of various combinations of low temperature flooding, freezing, and icing on stress resistance and cellular processes of Fredrick winter wheat. After 4 and 7 weeks of cold acclimation, groups of flats were removed from the growth cabinet and the leaves were trimmed...

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Section: Introductionmentioning

confidence: 99%

“…Membrane permeability to amino acids and salts increases markedly during ice encasement or exposure to CO2 and ethanol at -1°C (4).…”

mentioning

confidence: 99%

Interactions among Flooding, Freezing, and Ice Encasement in Winter Wheat

Gao¹,

Andrews²,

Pomeroy³

1983

Plant Physiol.

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“…The initial decrease can be attributed to the effects of anaerobiosis as a decrease in FR did not occur in leaves treated similarly but under aerobic conditions. Andrews and Pomeroy (2) showed that the anaerobic metabolite lactic acid increased during the 1st d of ice encasement and then remained constant.…”

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confidence: 99%

“…Two cultivars of wheat were compared, Kharkov winter wheat which has a high tolerance to ice encasement (2) and Gatcher spring wheat. During the first day under N2 at0WC, the FR of the leaves of both cultivars decreased by more than 50%o and thereafter decreased much more slowly.…”

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confidence: 99%

Stress Tolerance and Stress-Induced Injury in Crop Plants Measured by Chlorophyll Fluorescence In Vivo

1983

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The proposition is examined that measurements of chorophyll fluorescence in vivo can be used to monitor cellular injury caused Damage to crop plants and reductions in yields are often brought about by unfavorable environmental conditions; these include extremes of temperature, lack or surfeit of H20, high solar UV radiation, excess soil salinity, and the presence of toxic pollutants. Looking to the future, however, it seems that some environmental stresses will inevitably intensify, and this, coupled with such practices as utilizing land marginally suited to agriculture and growing desirable crop plants in climates for which the plants are ill adapted, e.g. maize in high latitudes (6) and potatoes in the semitropics (3), are likely to create an increasing need for new stress-tolerant varieties. Presently, the incidence of salt contamination of soil is increasing (10) and there also is concern that temperatures worldwide may rise because of increasing concentrations of CO2 and methane in the atmosphere, and solar UV radiation reaching the earth may intensify (22)

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“…Ethanol is produced by flooded seedlings (1,18,19), ice encased leaves (2), root nodules (20), and tissues exposed to S02 and 03 (10). The endosperm of germinating castor bean endosperm is an appropriate model to study anaerobic stress and alcohol metabolism.…”

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confidence: 99%

Anaerobic Stress in Germinating Castor Bean, Ethanol Metabolism, and Effects on Subcellular Organelles

Donaldson¹,

Soochan²,

Zaras³

1985

Plant Physiol.

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Endosperms from castor beans (Ricinus communis) germinated for 0 to 6 days were exposed to anoxia for 0 to 15 hours. Ethanol, the only alcohol detected by gas chromatography in the tissue, accumulates to a concentration of 15 millimolar during the first 2 to 4 hours of anoxia and subsequently decreases. The absolute amount of ethanol varies from 10 micromoles per 5-day endosperm after 4 hours anoxia to less than 1 micromole in 2-day endosperm after 4 hours. Lactate content is 2 micromoles or less per endosperm. Alcohol dehydrogenase and pyruvate decarboxylase activities, which are localized in cytosolic fractions, are not greatly affected by anoxia. The recoveries of the marker enzymes and protein in endoplasmic reticulum (ER) and mitochondrial fractions decrease during anoxia. After 15 hours, the recovery of NADPH cytochrome c reductase is 15% of that in controls, fumarase is 50%, and catalase is 75%.Glyoxysomes and ER are capable ofconverting ethanol to acetaidehyde which was measured using the fluorogenic reagent, 5,5-dimethyl-1,3-cyclohexanedione. The glyoxysomal activity is dependent on a hydrogen peroxide-generating substrate and the ER is dependent on NADPH. However, these activities are less than 3% of the alcohol dehydrogenase activity.Hypoxic stress and alcoholic fermentation are common features of plant metabolism. Ethanol is produced by flooded seedlings (1, 18, 19), ice encased leaves (2), root nodules (20), and tissues exposed to S02 and 03 (10). The endosperm of germinating castor bean endosperm is an appropriate model to study anaerobic stress and alcohol metabolism. This tissue responds to anoxia by generating ethanol and smaller amounts of lactate (11). ER, mitochondria, and glyoxysomes, subcellular components which depend on 02 have been isolated and well characterized (3, 6, 21). The glyoxylate cycle has been shown to participate in ethanol metabolism (17). In the earlier investigation of anoxic castor bean endosperm, Kobr and Beevers (1 1) followed ethanol accumulation for 2 h in endosperms after 5 d germination. However, plant tissues are often capable of producing ethanol for longer periods of time (1,4).One purpose of this study was to determine the extent and regulation ofethanol production in castor bean during prolonged anoxia as a function of seedling age. Also, we examined the possibility that other alcohols might be produced and metabolized during anoxia. Because the endosperm initially contains very little carbohydrate (7), it was expected that little or no ethanol would be generated prior to the establishment of gluconeogenesis. We explored the possibility that the capacity for ethanol generation might be regulated by pyruvate decarboxylase and alcohol dehydrogenase, the enzymes responsible for the final steps of ethanol production.The second major aim of this study was to examine the subcellular locations of ethanol metabolism and the effects of anoxia on 02 requiring organelles. It has been reported that rat liver microsomal Cyt P450 and peroxisomal catalase are capable ...

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Toxicity of Anaerobic Metabolites Accumulating in Winter Wheat Seedlings during Ice Encasement

Cited by 48 publications

References 14 publications

Interactions among Flooding, Freezing, and Ice Encasement in Winter Wheat

Interactions among Flooding, Freezing, and Ice Encasement in Winter Wheat

Stress Tolerance and Stress-Induced Injury in Crop Plants Measured by Chlorophyll Fluorescence In Vivo

Anaerobic Stress in Germinating Castor Bean, Ethanol Metabolism, and Effects on Subcellular Organelles

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