The respiratory source of CO<sub>2</sub>

Farrar, J. F.

doi:10.1111/j.1365-3040.1985.tb01678.x

Cited by 73 publications

(37 citation statements)

References 126 publications

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“…Changing respiration rates have an important influence on the growth of plants in elevated COj (Poorter et aL, 1992), and contrasting responses observed in respiration of different species under long-term exposure to elevated CO2 have been reviewed extensively (Amthor, 1991;Farrar & Williams, 1991). In theory, the extra amounts of carbohydrate accumulated as a result of enhanced photosynthesis would be expected to increase respiration rates (Farrar, 1985), and some indication of this was shown here in Site 1 monoliths. Correlations between increased carbohydrate content and respiration rates of plants grown in elevated CO2 have been demonstrated (Poorter, Pot & Lambers, 1988;Thomas et aL, 1993), but these increases might only be transient, disappearing in later growth (Farrar & Williams, 1991).…”

Section: Discussionmentioning

confidence: 86%

Canopy gas exchange and growth of upland pasture swards in elevated CO₂

Wolfenden

Diggle

1995

New Phytologist

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SUMMARYVegetation monoliths (450 x 450 mm) from two contrasting upland grassland communities were grown in Solardomes in either ambient ait or ambient air enriched with 250 ppm CO.^. During the first two growing seasons measurements of canopy gas exchange showed that rates of photosynthesis of limestone swards were enhanced by growth in elevated CO^, by approx. 50",, during spring and early sumn-ier. Although canopy respiration vv^as also greater in elevated CO.^, the overall effect was an average increase of 33 "" in net CO.^ assimilation. Enhanced respiration rates persisted into the autumn, whereas the effect on photosynthesis diminished through the growing season, so that in September swards growing in high COj had net photosynthesis rates similar to, or even lower than those in ambient air. This response varied between swards of differing species composition. In acidic grassland no significant effects of CO.^ on respitation or net CO.^ uptake rates were detected at any time.The above ground productivity of limestone grassland was measured in several harvests throughout both seasons, and was not affected by COj concentration at any time. Similarly, the acidic grassland, harvested at the end of the second season, showed no significant effect of COj on above-ground biomass. The results suggest that increasing atmospheric CO^ concentration is unlikely to cause large changes in net primary productivity in these grasslands.

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Section: Discussionmentioning

confidence: 86%

Canopy gas exchange and growth of upland pasture swards in elevated CO₂

Wolfenden

Diggle

1995

New Phytologist

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“…(d) The period beyond I 10 to 120 h when death tion occurs reversibly until the residual proteins and lipids are no longer able to maintain the membrane structure. From nediate respiratory decline after root tip excision that moment, the release of lipases and proteases inside the )erennial problem of how respiration is controlled cell and the leakage of metabolites from it can only lead to (drate supply (9). The stimulation of respiration by cell death.…”

Section: Effects Of Sucrose Starvation On Respiration Rate Of Maize Rmentioning

confidence: 99%

“…Within 24 h starvation the root tip cells lost 25% of their DW; however, the WC increase (from 8. [5][6][7][8][9][10][11][12] suggests that the loss of DW is offset by the uptake of water into the cells. This loss of DW cannot be explained by a burst of metabolic reactions, because during this time the respiration rate continued to decrease slowly (Fig.…”

Section: Effects Of Sucrose Starvation On Respiration Rate Of Maize Rmentioning

confidence: 99%

Study of Glucose Starvation in Excised Maize Root Tips

Brouquisse¹,

James²,

Raymond³

et al. 1991

Plant Physiol.

161

159

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Excised maize (Zea mays) root tips were used to follow the effects of a prolonged glucose starvation. Respiration rate began to decrease immediately after excision, reaching 30 to 40% of its initial value after 20 hours, and then declined more slowly until death of the tissues, which occurred after 200 hours of starvation. During the whole process, respiration could be uncoupled by 2,4-dinitrophenol and the energy charge remained high. These results suggest that in excised maize root tips, respiration rate is essentially limited by the rate of biosyntheses (ATP-utilizing processes) rather than mitochondrial number. Carbohydrates are the main respiratory substrates for plants, furnishing the malate and the acetyl-CoA necessary for the functioning of the Krebs cycle. Fifteen years ago it was still considered that, during the day, photosynthesis allowed starch synthesis in such amounts that the plant, particularly the root system, was never deprived of sugars. However, it is now known that carbohydrate starvation is common in most higher plants. Indeed, microbial, insect, or herbivore attacks or reduction in light intensity or temperature may cause a substantial decrease in photosynthesis, and thus lead to starvation.Since the end of the seventies, carbohydrate starvation has been studied in a number of plant species: wheat (28, 29), maize (14, 18), barley (8), pearl millet (1), pea (20,26,27), soybean (13, 25), sycamore (7, 10, 12, 17), etc. These studies have shown that in most cases, sugar starvation triggers the following sequence in plant cells: (a) the depletion of intracellular carbohydrate content and the subsequent decrease of respiration (1,12,18,20,25); (b) the breakdown of lipids and proteins (1,7,12,28) and a decline in the respiratory quotient from 1 to 0.75 (18); (c) an increase in inorganic phosphate ( 12,17), phosphorylcholine (7, 17), and free amino acids (10), and a concomitant decline in nucleotides (17, 18) and glycolytic enzymatic activities (12); and (d) the more or less marked disappearance of some cell ultrastructures (1, 29).The origin of the respiratory decrease during starvation was first attributed to carbohydrate depletion, by way of limitation of the substrate either for respiration or for biosynthetic processes; however, some experiments showed that root respiration rate was not a simple function ofcarbohydrate supply (8). Journet and co-workers (12) reported that during starvation the decrease in uncoupled respiration of sycamore cells was attributable to a progressive decrease in the number of mitochondria per cell; these authors concluded that the availability of respiratory substrates for the mitochondria does not determine the respiration rate of starved cells.In the present work, we investigated changes in 02 consumption, different organic compounds (sugars, fatty acids, proteins, adenine nucleotides), enzyme activities, and physical parameters (fresh and dry weight, osmolarity) in excised maize (Zea mays) root tips from the beginning of glucose starvation to tissue dea...

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“…This is not unexpected, as both fungus and host will have bigb demands for energy (the fungus for growth, the host for defence), and respiration would thus be increased to provide both energy and the carbon skeletons needed for biosynthesis (Farrar, 1985). It should eventually be possible to relate the respiration of fungus and host to their underlying metabolic activities.…”

Section: Introductionmentioning

confidence: 99%

Respiration of Leaves of Barley Infected With Powdery Mildew: Increased Engagement of the Alternative Oxidase

Farrar

Rayns

1987

New Phytologist

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SUMMARYLeaves of barley cv. Maris Otter, susceptible to powdery mildew, show a large increase in respiration rate when infected with this fungus. About half of the increase is due to increased electron flow through the cytochrome chain and half through the alternative pathway. The alternative pathway shows increased engagement following infection but no increase in capacity. Respiration is not limited either by substrate or supply of inorganic phosphate. While the increase in activity of the cytochrome path may be due to adenylate regulation, that of the alternative path is not understood. The more resistant cvs Athos and Atem do not show alternative path activity following infection with mildew.

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The respiratory source of CO₂

Cited by 73 publications

References 126 publications

Canopy gas exchange and growth of upland pasture swards in elevated CO₂

Canopy gas exchange and growth of upland pasture swards in elevated CO₂

Study of Glucose Starvation in Excised Maize Root Tips

Respiration of Leaves of Barley Infected With Powdery Mildew: Increased Engagement of the Alternative Oxidase

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The respiratory source of CO2

Cited by 73 publications

References 126 publications

Canopy gas exchange and growth of upland pasture swards in elevated CO2

Canopy gas exchange and growth of upland pasture swards in elevated CO2

Study of Glucose Starvation in Excised Maize Root Tips

Respiration of Leaves of Barley Infected With Powdery Mildew: Increased Engagement of the Alternative Oxidase

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Product

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The respiratory source of CO₂

Canopy gas exchange and growth of upland pasture swards in elevated CO₂

Canopy gas exchange and growth of upland pasture swards in elevated CO₂