scholarly journals Chronicvs.Short-Term Acute O3Exposure Effects on Nocturnal Transpiration in Two Californian Oaks

2007 ◽  
Vol 7 ◽  
pp. 134-140 ◽  
Author(s):  
N. E. Grulke ◽  
E. Paoletti ◽  
R. L. Heath
Keyword(s):  
Gas Exchange ◽  
Water Loss ◽  
Exchange System ◽  
Short Term ◽  
Blue Oak ◽  
Unexposed Control ◽  
Nocturnal Transpiration ◽  
Gas Exchange System ◽  
Black Oak ◽  
Oak Seedlings

We tested the effect of daytime chronic moderate ozone (O3) exposure, short-term acute exposure, and both chronic and acute O3exposure combined on nocturnal transpiration in California black oak and blue oak seedlings. Chronic O3exposure (70 ppb for 8 h/day) was implemented in open-top chambers for either 1 month (California black oak) or 2 months (blue oak). Acute O3exposure (~1 h in duration during the day, 120–220 ppb) was implemented in a novel gas exchange system that supplied and maintained known O3concentrations to a leaf cuvette. When exposed to chronic daytime O3exposure, both oaks exhibited increased nocturnal transpiration (without concurrent O3exposure) relative to unexposed control leaves (1.8× and 1.6×, black and blue oak, respectively). Short-term acute and chronic O3exposure did not further increase nocturnal transpiration in either species. In blue oak previously unexposed to O3, short-term acute O3exposure significantly enhanced nocturnal transpiration (2.0×) relative to leaves unexposed to O3. California black oak was unresponsive to (only) short-term acute O3exposure. Daytime chronic and/or acute O3exposures can increase foliar water loss at night in deciduous oak seedlings.

Regulation of Carboxylation and Photosynthetic Oscillations During Sun-Shade Acclimation in Helianthus annuus Measured With a Rapid-Response Gas Exchange System

1988 ◽  
Vol 15 (2) ◽  
pp. 239 ◽  
Author(s):  
CB Osmond ◽  
V Oja ◽  
A Laisk
Keyword(s):  
Gas Exchange ◽  
Intercellular Co2 Concentration ◽  
Photosynthetic Apparatus ◽  
Co2 Concentration ◽  
Rapid Response ◽  
Exchange System ◽  
Dynamic Regulation ◽  
Bisphosphate Carboxylase ◽  
Shade Acclimation ◽  
Gas Exchange System

The consequences of acclimation from shade to sun and vice versa for regulated photosynthetic metabolism were examined in H. annuus. A rapid-response gas exchange system was used to assess changes in carboxylation-related parameters (mesophyll conductance, assimilatory charge and CO2 capacity) and to analyse oscillations in CO2 fixation following transfer to high CO2 concentration as a function of intercellular CO2 concentration and light intensity. Data showed a two- to threefold change in all carboxylation-related parameters during acclimation in either direction. Dynamic regulation of carboxylation, indicated by changes in oscillatory response as a function of CO2 concentration at light saturation, remained unchanged, consistent with concerted regulation of ribulose-1,5-bisphosphate carboxylase-oxygenase during acclimation. However, the light dependency of oscillations changed during acclimation from shade to sun, and the range of oscillation was closely tied to the maximum rate of steady-state photosynthesis at CO2 saturation. These data imply that changes in the light-absorbing and electron transport components of the photosynthetic apparatus underlie the shift in regulatory behaviour during acclimation.

Gas-blood PCO2 gradients during avian gas exchange

1975 ◽  
Vol 39 (3) ◽  
pp. 405-410 ◽  
Author(s):  
D. G. Davies ◽  
R. E. Dutton
Keyword(s):  
Gas Exchange ◽  
Exchange System ◽  
Arterial Pco2 ◽  
Charged Membrane ◽  
Venous Pco2 ◽  
Avian Lung ◽  
Gas Exchange System ◽  
Spontaneously Breathing ◽  
Membrane Mechanism ◽  
Mixed Venous

The avian respiratory system is a crosscurrent gas exchange system. One of the aspects of this type of gas exchange system is that end-expired PCO2 is greater than arterial PCO2, the highest possible value being equal to mixed venous PCO2. We made steady-state measurements of arterial, mixed venous, and end-expired PCO2 in anesthetized, spontaneously breathing chickens during inhalation of room air or 4–8% CO2. We found end-expired PCO2 to be higher than both arterial and mixed venous PCO2, the sign of the differences being such as to oppose passive diffusion. The observation that end-expired PCO2 was higher than arterial PCO2 can be explained on the basis of crosscurrent gas exchange. However, the observation that end-expired PCO2 exceeded mixed venous PCO2 must be accounted for by some other mechanism. The positive end-expired to mixed venous PCO2 gradients can be explained if it is postulated that the charged membrane mechanism suggested by Gurtner et al. (Respiration Physiol. 7: 173–187, 1969) is present in the avian lung.

scholarly journals Food production and gas exchange system using blue-green alga (Spirulina) for CELSS

1987 ◽  
Vol 7 (4) ◽  
pp. 7-10 ◽  
Author(s):  
Mitsuo Oguchi ◽  
Koji Otsubo ◽  
Keiji Nitta ◽  
Shigeki Hatayama
Keyword(s):  
Gas Exchange ◽  
Green Alga ◽  
Food Production ◽  
Blue Green Alga ◽  
Exchange System ◽  
Gas Exchange System

Photosynthesis and transpiration in large forest-grown Douglas-fir: interactions with apical control

1981 ◽  
Vol 59 (12) ◽  
pp. 2568-2576 ◽  
Author(s):  
Jerry W. Leverenz
Keyword(s):  
Gas Exchange ◽  
Exchange Rates ◽  
Pseudotsuga Menziesii ◽  
Net Photosynthesis ◽  
Douglas Fir ◽  
Exchange System ◽  
Apical Control ◽  
Lateral Shoots ◽  
Terminal Shoot ◽  
Gas Exchange System

Net photosynthesis, transpiration, and stomatal and residual conductances for current-year shoots of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) were measured in an open gas exchange system. Terminal shoots of branches and branchlets had larger stomatal and residual conductances, and net photosynthetic and transpiration rates than neighboring lateral shoots under conditions which did not limit gas exchange. The differences between terminal and lateral shoots occurred in both exposed and shaded branches and in trees of different dominance classes. For most of the study, current-year lateral shoots were lighter green than terminal shoots. There were no significant differences in shoot water potential or in the microenvironment between terminal and lateral shoots.Effects of apical control on gas exchange rates were strong in shoots subtending the dominant terminal shoot. These effects were not apparent four whorls from the terminal shoot, in agreement with the hypothesis that apical control can not be exerted at long distances from terminal shoots.

scholarly journals Validation of a Simplified, Portable Cardiopulmonary Gas Exchange System for Submaximal Exercise Testing~!2009-10-25~!2010-01-09~!2010-03-17~!

2010 ◽  
Vol 4 (1) ◽  
pp. 34-40 ◽  
Author(s):  
Andrew D. Miller ◽  
Paul R. Woods ◽  
Thomas P. Olson ◽  
Minelle L. Hulsebus ◽  
Kathy A. O'Malley ◽  
...  
Keyword(s):  
Gas Exchange ◽  
Exercise Testing ◽  
Submaximal Exercise ◽  
Exchange System ◽  
Submaximal Exercise Testing ◽  
Gas Exchange System

scholarly journals Determining the Effects of Abscisic Acid Drenches on Evapotranspiration and Leaf Gas Exchange of Tomato

HortScience ◽  
2011 ◽  
Vol 46 (11) ◽  
pp. 1512-1517 ◽  
Author(s):  
Manuel G. Astacio ◽  
Marc W. van Iersel
Keyword(s):  
Abscisic Acid ◽  
Gas Exchange ◽  
Shelf Life ◽  
Water Use ◽  
Water Loss ◽  
Leaf Gas Exchange ◽  
Short Term ◽  
Leaf Physiology ◽  
Rate Dependent ◽  
Short Period

It is common for plants in the retail market to receive inadequate water and lose aesthetic value within a short period of time. The plant hormone abscisic acid (ABA) is naturally produced in response to drought conditions and reduces transpiration (E) by closing the stomata. Thus, ABA may lengthen shelf life of retail plants by reducing water loss. Two studies were conducted to look at effects of ABA on plant water use and shelf life over a 13-day period and short-term effects of ABA on leaf physiology. The objective of the short-term study was to determine how quickly 100-mL drenches of 250 mg·L−1 ABA solution affect leaf gas exchange of tomatoes (Solanum lycopersicum ‘Supersweet 100’). ABA drenches reduced stomatal conductance (gS), E, and photosynthetic rate (Pn) within 60 min. After 2 h, E, gs, and Pn were reduced by 66%, 72%, and 55% respectively, compared with the control plants. In the13-day study, ABA was applied to tomatoes as a 100-mL drench at concentrations ranging from 0 to 1000 mg·L−1 and ABA effects on water use and time to wilting were quantified. Half of the plants were not watered after ABA application, whereas the other plants were watered as needed. In general, higher ABA concentrations resulted in less water use by both well-watered and unwatered plants. ABA delayed wilting of unwatered plants by 2 to 8 days (dependent on the dose) as compared with control plants. In well-watered plants, ABA reduced daily evapotranspiration (ET) for 5 days, after which there were no further ABA effects. Negative side effects of the ABA application were rate-dependent chlorosis of the lower leaves followed by leaf abscission. These studies demonstrate that ABA drenches rapidly close stomata, limit transpirational water loss, and can extend the shelf life of retail plants by up to 8 days, which exemplifies its potential as a commercially applied plant growth regulator.

Respiratory System

2019 ◽  
pp. 485-530
Author(s):  
Olga Carvalho ◽  
John N. Maina
Keyword(s):  
Gas Exchange ◽  
Respiratory System ◽  
Exchange System ◽  
Long Distance ◽  
Total Lung Volume ◽  
Disease Patterns ◽  
Long Distance Running ◽  
System P ◽  
Terrestrial Life ◽  
Gas Exchange System

The lung is the gas-exchange organ that provides oxygen and removes carbon dioxide from the blood. The environment in which animals live and their metabolic needs determine the evolved design of their gas exchange system. Gills are the primordial respiratory organs that evolved for water ‘breathing’, while other adaptive solutions evolved for bimodal breathing, that is, the ability to extract oxygen from both water and air. The transition to fully terrestrial life was accompanied by significant changes in dimensions of respiratory units (alveoli) which decreased in size, whereas the number of units and total lung volume increased, leading to more efficient gas exchange and oxygen supply. While the shape and make-up of lungs in humans suggest adaptations to long-distance running and possibly to the exposition of smoke caused by fire, the exposure of the human respiratory system to novel environments has brought about a diverse array of disease patterns, including lung cancer, autoimmune diseases, and infectious diseases.

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