PHYSIOLOGICAL AND BIOCHEMICAL STUDIES IN PLANT METABOLISM: III. THE EFFECTS OF STARVATION AND MECHANICAL STIMULATION ON THE RESPIRATORY METABOLISM OF THE FIRST LEAF OF THE WHEAT PLANT

1951 ◽  
Vol 29 (4) ◽  
pp. 383-402 ◽  
Author(s):  
D. W. A. Roberts
Keyword(s):  
Carbon Dioxide ◽  
Wheat Plant ◽  
Carbon Dioxide Tension ◽  
Temporary Increase ◽  
Respiratory Metabolism ◽  
Protein Nitrogen ◽  
Carbon Dioxide Output ◽  
A Value ◽  
Biochemical Studies ◽  
Physiological And Biochemical

The oxygen uptake and carbon dioxide output records of detached starving first leaves of wheat have been investigated. Small changes in the oxygen tension or carbon dioxide tension of the surrounding air do not make any difference in the records. The data obtained with the Barcroft method agree with those obtained by the Pettenkofer method. The form of the starvation air line is described. It is generally similar in the four quarters of the leaf but the senescent hump of the basal quarter is much flatter and its peak much lower than in the other three quarters. The total senescent hump carbon dioxide is shown to be proportional to the protein nitrogen in each of the four quarters. The effect on the air lines of rubbing and quartering the leaves is described. There is a great temporary increase in carbon dioxide output as a result of rubbing. This quickly subsides and the respiration rate after the rubbing settles down to a value slightly in excess of that prior to the rubbing. Rubbing and quartering have no effect on the R.Q. of the starving leaves.

Breathing in brief exercise

1960 ◽  
Vol 15 (4) ◽  
pp. 583-588 ◽  
Author(s):  
F. N. Craig ◽  
E. G. Cummings
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Uptake ◽  
Respiratory Exchange Ratio ◽  
Metabolic Cost ◽  
Carbon Dioxide Tension ◽  
Minute Volume ◽  
Carbon Dioxide Output ◽  
Respiratory Minute Volume ◽  
Before And After

Two men ran for 20 or 60 seconds while inhaling air, oxygen or 4% carbon dioxide. Inspired respiratory minute volume was determined for each breath. Ventilation increased suddenly in the first breath with minimal changes in end-expiratory carbon dioxide tension and respiratory exchange ratio to a rate that remained constant for 20 seconds before increasing further. The rate of carbon dioxide output was uniform during the first 20 seconds. A 12% grade did not increase ventilation or oxygen uptake during runs of 20 seconds, but in the first minute of recovery, ventilation was 64% greater than after level runs. Inhalation of oxygen inhibited ventilation by 24% in the 20-second periods before and after the end of a 60-second run. Inhalation of carbon dioxide begun at rest produced increments in ventilation and end-expiratory carbon dioxide tension that varied little during running and recovery. In the 20-second runs ventilation varied with speed but appeared independent of ultimate metabolic cost. Submitted on January 21, 1960

scholarly journals The duration of the recovery period following strenuous muscular exercise

1933 ◽  
Vol 113 (783) ◽  
pp. 327-344 ◽  
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Consumption ◽  
Normal Values ◽  
Recovery Period ◽  
Oxygen Intake ◽  
Respiratory Metabolism ◽  
Carbon Dioxide Output ◽  
Steady Level ◽  
Made In

There are a variety of ways in which the duration of the recovery period after exercise can be determined. The method most frequently employed depends upon observations of the respiratory metabolism. This method has been chosen because the respiratory changes due to exercise can be followed with reasonable ease and accuracy, and because these changes are among the last of the more obvious effects of the exercise to disappear during recovery. In addition, interesting data concerning the effects of exercise on respiratory metabolism can be collected during the determination of the duration of the recovery period when this method is used. In determining the duration of the recovery period by observation of the respiratory metabolism, it is necessary to decide when the carbon dioxide output and oxygen intake have returned to their normal values and are no longer affected by the process of recovery from the exercise. This decision has been made in a variety of ways by different investigators. Some have made one or more pre-exercise determinations of the subject's basal oxygen intake and carbon dioxide output. Recovery was said to be complete when the carbon dioxide output and oxygen consumption returned to these values after exercise. Others found that the oxygen consumption did not return to the pre-exercise level within a reasonable length of time, but remained above normal for several hours. They considered that recovery was complete when the carbon dioxide output and oxygen intake returned to a steady level after exercise, even if the level was not the same as that before exercise.

The Acid-Base Status of the Blood of the Developing Chick Embryo

1969 ◽  
Vol 50 (1) ◽  
pp. 79-86
Author(s):  
C. DAWES ◽  
K. SIMKISS
Keyword(s):  
Carbon Dioxide ◽  
Chick Embryo ◽  
Base Excess ◽  
Carbon Dioxide Tension ◽  
Chick Embryos ◽  
Acid Base ◽  
A Value ◽  
Acid Base Status

1. The pH, carbon dioxide tension, bicarbonate and base excess levels of chick embryos have been measured during the period of 11 days of incubation until the 2nd day post hatching. 2. The carbon dioxide tension rises continuously from a value of about 20 mm. Hg on day 11 to a maximum of almost 60 mm. Hg on day 19. 3. The bicarbonate content rises rapidly from the 12th day (16 m-equiv./l.) until the 16th day (33 m-equiv./l.). 4. The pH falls to minimum values on the 13-14th day and the 19th day. 5. These variations are discussed in relation to the physiology of the developing embryo and its acid-base metabolism.

A CONTRIBUTION TO THE STUDY OF DORMANCY IN SEEDS: LACTUCA SATIVA L.

1948 ◽  
Vol 26c (2) ◽  
pp. 194-217 ◽  
Author(s):  
C. W. Leggatt
Keyword(s):  
Carbon Dioxide ◽  
Blue Light ◽  
Seed Coat ◽  
Respiratory Metabolism ◽  
Carbon Dioxide Output ◽  
Lettuce Seeds ◽  
Inhibiting Factors ◽  
Lactuca Sativa L ◽  
Other Substances ◽  
Light Effects

The ease with which lettuce seeds may be made dormant by placing them under germinating conditions in blue light suggested that this kind of seed would provide satisfactory material for a study of certain aspects of dormancy in seeds. Studies have been made of the behavior of lettuce seeds under varied conditions of moisture, atmosphere, color of light, and integrity of the testa. Measurements of the absolute respiration have provided curves of the drift with time of carbon dioxide output, oxygen uptake, and of respiratory quotient. Experiments with substances that might induce dormancy and light-sensitiveness similar to that induced by blue light have been made. The bearing of the results obtained upon possible metabolic changes in the seed are discussed.The possibility that the observed effects of light upon seed germination are due to changes in the permeability of the seed coat induced by light is considered as untenable, but this does not exclude the fact that the seed coat is a restrictive agency to the free passage of oxygen, carbon dioxide, and other substances. Indeed, in any description of the probable metabolic state, this must certainly be considered. While it has not been possible to formulate a definite biochemical scheme to account for blue light effects, the experimental evidence suggests that 'carbon dioxide zymasis' may be promoted by blue light and that carbon dioxide may be one of the inhibiting factors. The blue light dormant condition is characterized by depressed respiration but without more disturbance of the equilibrium of the pre- and postglycolytic phases of respiratory metabolism than is found to be characteristic of uninhibited seeds as reported by other workers.The results of this research suggest that further elucidation of the phenomenon of dormancy should be sought in the direction of more extended studies of the respiration of dormant and non-dormant seeds.

Physiological and biochemical studies in plant metabolism. IV. Effect of illumination and darkness on the physiological heterogeneity in the first leaf of wheat

1951 ◽  
Vol 29 (4) ◽  
pp. 451-466 ◽  
Author(s):  
D.W.A. Roberts
Keyword(s):  
Respiratory Rate ◽  
Nitrogen Content ◽  
Leaf Anatomy ◽  
Soluble Nitrogen ◽  
Plant Metabolism ◽  
Sucrose Content ◽  
Protein Nitrogen ◽  
Biochemical Studies ◽  
Physiological And Biochemical ◽  
Physiological Heterogeneity

The respiratory rate, soluble nitrogen content, protein nitrogen content, water content, reducing substance content, and sucrose content of each of the four quarters of the first leaf of Khapli wheat have been determined after different exposures to light under standardized conditions. The respiratory rate of the different quarters of the leaf as a whole is not determined by the distribution of any of the above mentioned constituents. Protein, water, and sucrose distribution appear to be correlated with the anatomy of the leaf. Leaf anatomy is apparently an important consideration in the physiological heterogeneity of the first leaf of wheat.

Gas Exchange during Exercise in Healthy People: I. the Physiological Dead-Space Volume

1976 ◽  
Vol 51 (4) ◽  
pp. 323-333 ◽  
Author(s):  
Christine A. Bradley ◽  
E. A. Harris ◽  
Eve R. Seelye ◽  
R. M. L. Whitlock
Keyword(s):  
Carbon Dioxide ◽  
Dead Space ◽  
Confidence Limit ◽  
Carbon Dioxide Tension ◽  
Physiological Dead Space ◽  
Carbon Dioxide Output ◽  
Pulmonary Capillary ◽  
Dead Space Volume ◽  
Capillary Temperature ◽  
Space Volume

1. Physiological dead-space volume (VD) was measured in twenty-four healthy men and women aged from 20 to 71 years, at rest and at two rates of work on a treadmill, whilst breathing air and breathing oxygen. 2. The effect of correction of arterial carbon dioxide tension (Pa,co2) to pulmonary capillary temperature on the resulting value for VD was investigated. We find that the effect is substantial and that a correction should be made. 3. Equations have been derived for the prediction of normal VD during exercise. The best prediction was given by a regression on height, age, carbon dioxide output, ventilation and respiratory frequency, with an upper 95% confidence limit of +81 ml.

The effect of a reduction in expired carbon dioxide on the attractiveness of human subjects to mosquitoes

1970 ◽  
Vol 60 (1) ◽  
pp. 43-48 ◽  
Author(s):  
W. F. Snow
Keyword(s):  
Carbon Dioxide ◽  
West Africa ◽  
Species Differences ◽  
Human Subjects ◽  
Carbon Dioxide Output ◽  
A Value ◽  
Breathing Apparatus ◽  
Medium Range ◽  
Close Range ◽  
The Subject

The attractiveness, to mosquitoes, of human subjects breathing normally and wearing a breathing apparatus which removed 95·5% of expired carbon dioxide were compared in the field. Significantly fewer mosquitoes approached the subject with a reduced carbon-dioxide output. Species differences were apparent in the degree of reduction of mosquitoes at the bait, as measured by the ratio of numbers attracted to subjects without and with the breathing apparatus. From the results of trials in the Gambia, West Africa, this ratio gave values of 0·67 for Mansonioides spp., 0·46 for Anopheles gambiae Giles/A. melas Theo. and 0·19 for Culex thalassius Theo., while complementary work in southern England gave a value of 0·34 for Aedes cantans (Mg.)/Ae. annulipes (Mg.). A reduced carbon-dioxide output had no effect on the proportion of mosquitoes attempting to feed once within close range of the host. These findings confirm that carbon dioxide is a long- or medium-range attractant.

Global carbon dioxide output of volcanic lakes in the Azores archipelago, Portugal

2021 ◽  
pp. 106835
Author(s):  
César Andrade ◽  
Fátima Viveiros ◽  
J. Virgílio Cruz ◽  
Rui Coutinho
Keyword(s):  
Carbon Dioxide ◽  
Azores Archipelago ◽  
Carbon Dioxide Output ◽  
Volcanic Lakes ◽  
Global Carbon
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