scholarly journals Researches on plant respiration. II.―Variations in the respiratory quotient during germination of seeds with different food reserves

1933 ◽  
Vol 113 (784) ◽  
pp. 405-428 ◽  
Keyword(s):  
Carbon Dioxide ◽  
Respiratory Quotient ◽  
Respiratory Activity ◽  
Oxygen Adsorption ◽  
Carbon Dioxide Evolution ◽  
Food Reserves ◽  
Plant Respiration ◽  
Germinating Seeds ◽  
True Measure

Determinations of respiratory activity in plants have nearly always been made by measuring the rate of carbon dioxide evolution by the tissues. Much less frequently the rate of oxygen adsorption has been used as a measure of the process. In comparatively few researches have determinations been made of both carbon dioxide evolution and oxygen adsorption. Yet it is clear that a true measure of respiratory activity can only be given by one or other of these quantities alone, it they bear a fixed numerical relation to one another; where this is not so, it is obvious that at least one of these quantities cannot be taken as a measure of respiration, and it may not always easy in such cases to decide which of them is to be regarded as giving the truer value of this process. Indeed, a determination of both carbon dioxide output and oxygen adsorption by respiring tissues seems eminently desirable as providing data allied should assist in the elucidation of the mechanism of the respiratory process. In the work described in this paper, which deals with the course of respiratory activity of plants of a number of species during germination of the seeds and the early development of the seedling, we have accordingly determined not only the rate of carbon dioxide evolution, but the rate of oxygen adsorption. Such determinations appear to be the more desirable as the existing information on the respiratory quotient of germinating seeds is scanty, and such data as have been recorded are highly contradictory.

Variation in the respiratory quotient of birds and implications for indirect calorimetry using measurements of carbon dioxide production

1995 ◽  
Vol 198 (1) ◽  
pp. 213-219 ◽  
Author(s):  
G Walsberg ◽  
B Wolf
Keyword(s):  
Carbon Dioxide ◽  
Power Consumption ◽  
Indirect Calorimetry ◽  
Respiratory Quotient ◽  
Current Knowledge ◽  
Bird Species ◽  
Passer Domesticus ◽  
Carbon Dioxide Production ◽  
Accurate Estimation

Determination of animal power consumption by indirect calorimetry relies upon accurate estimation of the thermal equivalent of oxygen consumed or carbon dioxide produced. This estimate is typically based upon measurement or assumption of the respiratory quotient (RQ), the ratio of CO2 produced to O2 consumed. This ratio is used to indicate the mixture of lipids, carbohydrates and proteins in the metabolic substrate. In this analysis, we report the RQ for two bird species, Passer domesticus and Auriparus flaviceps, under several dietary and fasting regimes. RQ commonly differed substantially from those typically assumed in studies of energy metabolism and often included values below those explainable by current knowledge. Errors that could result from these unexpected RQ values can be large and could present the primary limit to the accuracy of power consumption estimates based upon measurement of carbon dioxide production.

scholarly journals SILICON METABOLISM IN DIATOMS

1955 ◽  
Vol 39 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Joyce C. Lewin
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Uptake ◽  
Respiratory Quotient ◽  
Aerobic Respiration ◽  
Carbon Dioxide Evolution ◽  
Exogenous Glucose ◽  
Silicon Uptake ◽  
Silicon Metabolism ◽  
Respiratory Stimulation ◽  
Stimulation Of

1. Evidence is presented that silicon uptake in the diatom Navicula pelliculosa is linked with aerobic respiration. 2. Cyanide, fluoride, iodoacetate, arsenite, azide, and fluoroacetate, at concentrations inhibitory to respiration, were also inhibitory to silicon uptake. 3. 2,4-Dinitrophenol (1 to 2 x 10–5 M) stimulated respiration by 100 per cent, but almost completely inhibited silicon uptake. 4. The respiratory quotient of non-Si-deficient cells decreased from 0.93 to 0.75 after 4 days of starvation in darkness. Glucose (1 per cent) raised the respiratory quotient of such starved cells to 1.05. 5. Silicate (20 mg. Si/liter) stimulated respiration of unstarved Si-deficient cells by about 40 per cent. The effect of silicate on the respiration of Si-deficient cells which had been starved in darkness for 4 days was less marked. 6. The respiratory quotient of Si-deficient cells decreased from 0.8–0.9 to 0.3 after 4 days of starvation in darkness. The addition of silicate to starved cells raised the quotient to 0.5. This represented a 25 per cent stimulation of oxygen uptake concomitant with a 90 per cent stimulation of carbon dioxide evolution. 7. Glucose (1 per cent) caused an increase of respiratory quotient in starved cells from 0.3 to 0.7–0.8. The addition of silicate had no effect on the R.Q. during the oxidation of exogenous glucose. 8. Substrates (glucose, fructose, galactose, lactate, succinate, citrate, glycerol), which caused a stimulation of respiration in starved cells, also stimulated silicon uptake by those cells. However, the stimulation of silicon uptake (50 to 100 per cent) was not proportional to the respiratory stimulation by these substrates (30 to 300 per cent).

scholarly journals Determination of Carbon Dioxide Evolution Rates Using a Novel Noninstrumental Microrespirometer

2000 ◽  
Vol 83 (2) ◽  
pp. 277-281 ◽  
Author(s):  
Yuch-Ping Hsieh ◽  
Yun-Hwa P Hsieh
Keyword(s):  
Carbon Dioxide ◽  
Environmental Samples ◽  
Laboratory Studies ◽  
Carbon Dioxide Absorption ◽  
Carbon Dioxide Evolution ◽  
Acid Base ◽  
Liquid Samples ◽  
The Cost ◽  
Instrumental Methods

Abstract A novel noninstrumental microrespirometer was developed to determine carbon dioxide evolution rates of solid or liquid samples at μL/h levels accurately and rapidly. The respirometer is based on the simple principle of acid–base titration at a steady-state of carbon dioxide absorption/evolution. The structure and operation of the microrespirometer are simple and the cost is modest in comparison to instrumental methods. The microrespirometer is suitable for laboratory studies and field routine examinations of food, agricultural, and environmental samples.

scholarly journals Researches on plant respiration IV— The relation between the respiration in air and in nitrogen of certain seeds during germination, (b) seeds in which carbohydrates constitute the chief food reserve

1936 ◽  
Vol 119 (815) ◽  
pp. 507-521 ◽  
Keyword(s):  
Experimental Data ◽  
Similar Data ◽  
Food Reserve ◽  
Respiration Rates ◽  
Food Reserves ◽  
Plant Respiration ◽  
Germinating Seeds

Part III of this series (Leach and Dent, 1934) dealt with experimental data concerning the effect on the respiration rates and respiratory quotients of certain fat-storing germinating seeds when successively surrounded by atmospheres of air, nitrogen, and air. The present paper describes similar data relating to the respiration of germinating seeds in which the predominant food reserves are carbohydrates. The seeds used in the present investigation, as with those used in the previous one, were of species belonging to genera widely separated from one another phyletically. The seeds were all obtained from Messrs.Sutton & Sons of Reading and the species and varieties used were as.

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