scholarly journals Observations on Gas Exchange in the Developing Sultana Berry

1968 ◽  
Vol 21 (5) ◽  
pp. 907 ◽  
Author(s):  
PE Kriedemann
Keyword(s):  
Gas Exchange ◽  
Oxygen Uptake ◽  
Respiratory Quotient ◽  
Photosynthetic Activity ◽  
Dark Respiration ◽  
Grape Berry ◽  
High Rate ◽  
Early Phases

In its early phases of growth the grape berry, although lacking stomata, shows measurable photosynthetic activity. There also exists a capacity for dark C02 fixation following a period of illumination and a relatively high rate of dark respiration (expressed as 02 uptake) with a respiratory quotient which is less than unity. Oxygen uptake can be completely arrested by illumination.

Sodium fluoride induced metabolic changes in jack pine seedlings. I. Effect on gas exchange, water content, and carbohydrates

1988 ◽  
Vol 18 (10) ◽  
pp. 1305-1310 ◽  
Author(s):  
J. J. Zwiazek ◽  
Jennifer M. Shay
Keyword(s):  
Water Stress ◽  
Gas Exchange ◽  
Water Content ◽  
Sodium Fluoride ◽  
Respiratory Quotient ◽  
Dark Respiration ◽  
Jack Pine ◽  
Metabolic Changes ◽  
Fluoride Treatment ◽  
Pine Seedlings

Dark respiration, photosynthesis, water content, and carbohydrate pools were examined in jack pine (Pinusbanksiana Lamb.) seedlings treated for 1–7 days with sodium fluoride. Compared with those of controls, both respiratory rates and respiratory quotient decreased in plants treated for 1 day. Photosynthetic rates declined in plants exposed to fluoride for 1, 2, and 4 days. Recovery was observed in seedlings treated for 7 days. A decrease in water content was noted as early as 1 day after the exposure of plants to fluoride, and seedlings treated for longer periods continued to contain less water than control plants. The following effects of sodium fluoride treatment on carbohydrates were observed. Firstly, inositol increased in plants after 1 day, glucose increased after 1 and 2 days, and starch significantly declined in plants treated for 1 day. Sucrose was also initially present in lower amounts in fluoride-treated seedlings. Plants treated for 7 days contained levels of sucrose similar to those of controls. The possibility that water stress may be partly responsible for some of the metabolic changes is discussed.

scholarly journals Heatwave frequency and seedling death alter stress-specific emissions of volatile organic compounds in Aleppo pine

Oecologia ◽  
2021 ◽  
Author(s):  
Benjamin Birami ◽  
Ines Bamberger ◽  
Andrea Ghirardo ◽  
Rüdiger Grote ◽  
Almut Arneth ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Gas Exchange ◽  
Organic Compounds ◽  
Stress Responses ◽  
Methyl Salicylate ◽  
Environmental Changes ◽  
Pinus Halepensis ◽  
Dark Respiration ◽  
Seedling Mortality ◽  
Volatile Organic

AbstractBiogenic volatile organic compounds (BVOC) play important roles in plant stress responses and can serve as stress indicators. While the impacts of gradual environmental changes on BVOCs have been studied extensively, insights in emission responses to repeated stress and recovery are widely absent. Therefore, we studied the dynamics of shoot gas exchange and BVOC emissions in Pinus halepensis seedlings during an induced moderate drought, two four-day-long heatwaves, and the combination of drought and heatwaves. We found clear stress-specific responses of BVOC emissions. Reductions in acetone emissions with declining soil water content and transpiration stood out as a clear drought indicator. All other measured BVOC emissions responded exponentially to rising temperatures during heat stress (maximum of 43 °C), but monoterpenes and methyl salicylate showed a reduced temperature sensitivity during the second heatwave. We found that these decreases in monoterpene emissions between heatwaves were not reflected by similar declines in their internal storage pools. Because stress intensity was extremely severe, most of the seedlings in the heat-drought treatment died at the end of the second heatwave (dark respiration ceased). Interestingly, BVOC emissions (methanol, monoterpenes, methyl salicylate, and acetaldehyde) differed between dying and surviving seedlings, already well before indications of a reduced vitality became visible in gas exchange dynamics. In summary, we could clearly show that the dynamics of BVOC emissions are sensitive to stress type, stress frequency, and stress severity. Moreover, we found indications that stress-induced seedling mortality was preceded by altered methanol, monoterpene, and acetaldehyde emission dynamics.

Pulmonary Gas Exchange and Oxygen Uptake During Exercise in Patients with Type 1 Diabetes Mellitus

1992 ◽  
Vol 9 (3) ◽  
pp. 252-257 ◽  
Author(s):  
Th. Wanke ◽  
D. Formanek ◽  
M. Auinger ◽  
H. Zwick ◽  
K. Irsigler
Keyword(s):  
Diabetes Mellitus ◽  
Type 1 Diabetes ◽  
Gas Exchange ◽  
Oxygen Uptake ◽  
Type 1 Diabetes Mellitus ◽  
Pulmonary Gas Exchange

Ciliary Activity and Oxygen uptake in Branchiostoma Lanceolatum(Pallas)

1965 ◽  
Vol 43 (1) ◽  
pp. 1-12
Author(s):  
W. A. M. COURTNEY ◽  
R. C. NEWELL
Keyword(s):  
Oxygen Uptake ◽  
High Rate ◽  
Ciliary Activity ◽  
Oxygen Utilization ◽  
Nervous Control ◽  
Pharyngeal Wall ◽  
Temperature Range ◽  
Zero Rate ◽  
Branchiostoma Lanceolatum ◽  
Set Up

1. The rate of oxygen uptake by single specimens of Branchiostoma lanceolatum has been shown to vary considerably. Some animals in sealed vessels at 50° C. were able to utilize the oxygen linearly down to less than 20% of air saturation. Others ceased to absorb oxygen at high saturations while yet others displayed two different rates in a sequence starting initially with a high rate. 2. There are three possible rates of oxygen utilization, as well as a zero rate, for an animal at any temperature between 10 and 19° C. Animals in gravel exhibit only two rates at lower temperatures. 3. The slowest rate varies exponentially with temperature but the two faster rates show a rapid increase between 10 and 15° C. with little change outside this temperature range. 4. The effect of size and temperature on the increased oxygen uptake during the faster rates of respiration are discussed. It is suggested that ciliary activity of the pharynx could be associated with the extra oxygen utilization. 5. It has been found that there are three inhalant stream velocities, a fast, a slow and a zero rate with no intermediate rates. 6. Study of the isolated portions of the pharyngeal wall confirm that the fast inhalant current is set by the activity of all the cilia to give a feeding stream. The slow stream is set up by the lateral cilia, which continue to beat when the frontal cilia and most of the lateral cilia have been inhibited by lowered oxygen concentrations. 7. The lateral cilia have been shown to be under nervous control and to be inhibited by pressure on the pharyngeal bars. This mechanism depends on the presence of a connexion between the pharyngeal bars and the endostyle.

scholarly journals Coca chewing for exercise: hormonal and metabolic responses of nonhabitual chewers

1996 ◽  
Vol 81 (5) ◽  
pp. 1901-1907 ◽  
Author(s):  
Roland Favier ◽  
Esperanza Caceres ◽  
Laurent Guillon ◽  
Brigitte Sempore ◽  
Michel Sauvain ◽  
...  
Keyword(s):  
Heart Rate ◽  
Gas Exchange ◽  
Oxygen Uptake ◽  
Metabolic Responses ◽  
Physiological Data ◽  
Respiratory Gas Exchange ◽  
Gum Chewing ◽  
Arterial Blood ◽  
Before And After ◽  
Exercise Induced

Favier, Roland, Esperanza Caceres, Laurent Guillon, Brigitte Sempore, Michel Sauvain, Harry Koubi, and Hilde Spielvogel. Coca chewing for exercise: hormonal and metabolic responses of nonhabitual chewers. J. Appl. Physiol. 81(5): 1901–1907, 1996.—To determine the effects of acute coca use on the hormonal and metabolic responses to exercise, 12 healthy nonhabitual coca users were submitted twice to steady-state exercise (∼75% maximal O2 uptake). On one occasion, they were asked to chew 15 g of coca leaves 1 h before exercise, whereas on the other occasion, exercise was performed after 1 h of chewing a sugar-free chewing gum. Plasma epinephrine, norepinephrine, insulin, glucagon, and metabolites (glucose, lactate, glycerol, and free fatty acids) were determined at rest before and after coca chewing and during the 5th, 15th, 30th, and 60th min of exercise. Simultaneously to these determinations, cardiorespiratory variables (heart rate, mean arterial blood pressure, oxygen uptake, and respiratory gas exchange ratio) were also measured. At rest, coca chewing had no effect on plasma hormonal and metabolic levels except for a significantly reduced insulin concentration. During exercise, the oxygen uptake, heart rate, and respiratory gas exchange ratio were significantly increased in the coca-chewing trial compared with the control (gum-chewing) test. The exercise-induced drop in plasma glucose and insulin was prevented by prior coca chewing. These results contrast with previous data obtained in chronic coca users who display during prolonged submaximal exercise an exaggerated plasma sympathetic response, an enhanced availability and utilization of fat (R. Favier, E. Caceres, H. Koubi, B. Sempore, M. Sauvain, and H. Spielvogel. J. Appl. Physiol. 80: 650–655, 1996). We conclude that, whereas coca chewing might affect glucose homeostasis during exercise, none of the physiological data provided by this study would suggest that acute coca chewing in nonhabitual users could enhance tolerance to exercise.

scholarly journals Effect of biostimulants on dry matter accumulation and gas exchange in plantain plants (Musa AAB)

2019 ◽  
Vol 13 (2) ◽  
pp. 151-160
Author(s):  
Diana Mateus-Cagua ◽  
Gustavo Rodríguez-Yzquierdo
Keyword(s):  
Gas Exchange ◽  
Dry Matter ◽  
Photosynthetic Activity ◽  
Leaf Gas Exchange ◽  
Block Design ◽  
Dry Matter Accumulation ◽  
Vegetative Phase ◽  
Physiological Processes ◽  
Randomized Complete Block Design ◽  
Positive Effect

Biostimulants can potentially improve plant growth and development, modifying physiological processes. This study evaluated the effect of four biostimulants on the growth of ‘Hartón’ plantain plants and the leaf gas exchange during the vegetative phase. This experiment was developed on a plantain farm’s nursery in Fuente de Oro (Colombia) with a randomized complete block design with four replicates. The treatments were the biostimulants: Bactox WP®: Bacillus subtilis (Bs); Baliente®: Bacillus amyloliquefaciens (Ba); Tierra Diatomeas®: silicon dioxide (Si); Re-Leaf®: salicylic acid (SA) and the control (water). All products had a positive effect on the accumulation of total dry matter (DM) (between 58.4 and 21.9%) and on the photosynthetic activity (a maximum of 110 and 24.3% in first and second evaluation), as compared to the control, while no differences were found (P>0.05) for the foliar emission rate and chlorophyll content between the treatments. The plants treated with Bs had the greatest DM accumulation at the end of the study and a constant, high photosynthetic activity. All the while Bs, Ba and Si managed to stimulate greater early photosynthetic activity. According to the results, the use of these biostimulants during the vegetative phase had an effect on the physiological processes that enhance DM accumulation in plantain plants, which could be potentially useful for the transplanting stage and increase the reserves used during their establishment and development in the field.

Physical capacity, respiratory quotient and energy expenditure during exercise in male patients with schizophrenia compared with healthy controls

2012 ◽  
Vol 27 (3) ◽  
pp. 206-212 ◽  
Author(s):  
B.M. Nilsson ◽  
R.M. Olsson ◽  
A. Öman ◽  
F.-A. Wiesel ◽  
L. Ekselius ◽  
...  
Keyword(s):  
Weight Gain ◽  
Energy Expenditure ◽  
Oxygen Uptake ◽  
Maximal Oxygen Uptake ◽  
Respiratory Quotient ◽  
Physical Capacity ◽  
Healthy Controls ◽  
Uptake Capacity ◽  
Everyday Activity ◽  
Male Patients

AbstractBackgroundDespite massive research on weight gain and metabolic complications in schizophrenia there are few studies on energy expenditure and no current data on physical capacity.AimTo determine oxygen uptake capacity, respiratory quotient (RQ) and energy expenditure during a submaximal exercise test in patients with schizophrenia and healthy controls.MethodTen male patients and 10 controls were included. RQ and energy expenditure were investigated with indirect calorimetry during a cycle ergometer test. The submaximal work level was defined by heart rate and perceived exhaustion. Physical capacity was determined from predicted maximal oxygen uptake capacity (VO2-max).ResultsThe patients exhibited significantly higher RQ on submaximal workloads and lower physical capacity. A significant lower calculated VO2-max remained after correction for body weight and fat free mass (FFM). Energy expenditure did not differ on fixed workloads.ConclusionRQ was rapidly increasing in the patients during exercise indicating a faster transition to carbohydrate oxidation and anaerobic metabolism that also implies a performance closer to maximal oxygen uptake even at submaximal loads. This may restrict the capacity for everyday activity and exercise and thus contribute to the risk for weight gain. Physical capacity was consequently significantly lower in the patients.

Some Aspects of Gas Exchange in Tuna

1972 ◽  
Vol 56 (3) ◽  
pp. 809-823
Author(s):  
E. D. STEVENS
Keyword(s):  
Hydrostatic Pressure ◽  
Gas Exchange ◽  
Oxygen Uptake ◽  
Average Rate ◽  
Oxygen Removal ◽  
Skipjack Tuna ◽  
Partial Pressure Of Oxygen ◽  
Free Swimming ◽  
Flow Rates ◽  
Theoretical Predictions

1. Some aspects of gas exchange in restrained skipjack tuna were analysed. 2. The average rate at which water flowed over the gills was 2.81/min. kg. 3. The concentration of oxygen in water entering and leaving the gills was measured and used to calculate oxygen uptake (692 mg/h.kg) and utilization (0.71). 4. The drop in hydrostatic pressure as water flowed over the gills was 1.9 cm water and agrees favourably with theoretical predictions. 5. The partial pressure of oxygen was measured in blood afferent and efferent to the gills and used to calculate effectiveness of oxygen removal from the water (90%) and the transfer factor for oxygen (0.12 ml/min.kg.mmHg). 6. The average utilization measured in free-swimming tuna was 0.56. 7. The extraordinary ability of tuna to efficiently extract oxygen from the water at high gill water flow rates is discussed.

Ventilation and gas exchange in lizards during treadmill exercise.

1997 ◽  
Vol 200 (20) ◽  
pp. 2629-2639
Author(s):  
T Wang ◽  
D R Carrier ◽  
J W Hicks
Keyword(s):  
Exchange Rate ◽  
Gas Exchange ◽  
Oxygen Uptake ◽  
Minute Ventilation ◽  
Oxygen Demand ◽  
Lung Ventilation ◽  
Iguana Iguana ◽  
Maximal Aerobic Speed ◽  
Gas Exchange Rate ◽  
Treadmill Locomotion

The extent to which lizards ventilate their lungs during locomotion is controversial. Direct measurements of airflow across the nostrils suggest a progressive reduction in tidal volume and minute ventilation with increased running speed, while other studies have demonstrated that arterial PO2 remains constant during exercise. To resolve these conflicting findings, we measured minute ventilation and gas exchange rate in five specimens of Varanus exanthematicus and five specimens of Iguana iguana during treadmill locomotion at speeds between 0.14 and 1.11ms-1 at 35 degrees C. These speeds are much lower than maximal running speeds, but are greater than the maximal aerobic speed. In both species, the ventilatory pattern during locomotion was highly irregular, indicating an interference between locomotion and lung ventilation. In Varanus exanthematicus, treadmill locomotion elicited a six- to eightfold increase in minute ventilation from a pre-exercise level of 102mlkg-1min-1, whereas the rate of oxygen uptake increased approximately threefold (from 3.9 to 12.6mlkg-1min-1). After exercise, both minute ventilation and gas exchange rate decreased immediately. Because minute ventilation increased more than did oxygen consumption, an increase in lung PO2 during exercise is predicted and, thus, Varanus exanthematicus appears effectively to ventilate its lungs to match the increased metabolic rate during locomotion at moderate speed. In Iguana iguana, both minute ventilation and gas exchange rate increased above resting values during locomotion at 0.28ms-1, but both decreased with further increases in locomotor speed. Furthermore, following exercise, both minute ventilation and oxygen uptake rate increased significantly. Iguana iguana, therefore, appears to be unable to match the increased oxygen demand with adequate ventilation at moderate and higher speeds.

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