A field portable gas-exchange system for measuring carbon dioxide and water vapour exchange rates of leaves during fumigation with SO2

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.

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Environmental regulation of the oxygen effect on apparent photosynthesis in wheat

Canadian Journal of Botany ◽

10.1139/b73-107 ◽

1973 ◽

Vol 51 (5) ◽

pp. 841-853 ◽

Cited By ~ 37

Author(s):

P. A. Jolliffe ◽

E. B. Tregunna

Keyword(s):

Carbon Dioxide ◽

Gas Exchange ◽

Environmental Regulation ◽

Environmental Conditions ◽

Compensation Point ◽

Oxygen Effect ◽

Exchange System ◽

Wide Range ◽

Gas Exchange System ◽

The Relationship

A closed gas exchange system was used to survey the apparent rates of photosynthesis by young wheat shoots in a wide range of O2 concentrations (O2), CO2 concentrations (CO2), temperatures (T), and radiant flux densities. The results are expressed graphically and by equations. The carbon dioxide compensation point (ΓH) conformed to the equation ΓH = O2e(0.0428T − 12.1). The relationship between the apparent rates of photosynthesis in the presence (PH) and absence (PL) of inhibitory concentrations of oxygen was described by the equation PH = PLk loge(CO2/ΓH) where k was independent of the prevailing environmental conditions and [Formula: see text].

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An installation for measuring carbon dioxide and water vapour exchange rates with a precise environmental control

Biologia Plantarum ◽

10.1007/bf02920792 ◽

1974 ◽

Vol 16 (2) ◽

pp. 144-148 ◽

Cited By ~ 7

Author(s):

J. Čatský ◽

Ingrid Tichá

Keyword(s):

Carbon Dioxide ◽

Exchange Rates ◽

Water Vapour ◽

Environmental Control

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

The Scientific World JOURNAL ◽

10.1100/tsw.2007.33 ◽

2007 ◽

Vol 7 ◽

pp. 134-140 ◽

Cited By ~ 16

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.

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Analysis of the gas exchange system dynamics during high-frequency ventilation

Annals of Biomedical Engineering ◽

10.1007/bf02484470 ◽

1986 ◽

Vol 14 (6) ◽

pp. 525-542 ◽

Cited By ~ 6

Author(s):

S. D. Ghazanshahi ◽

V. Z. Marmarelis ◽

S. M. Yamashiro

Keyword(s):

Gas Exchange ◽

System Dynamics ◽

High Frequency ◽

High Frequency Ventilation ◽

Exchange System ◽

Frequency Ventilation ◽

Gas Exchange System

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

Functional Plant Biology ◽

10.1071/pp9880239 ◽

1988 ◽

Vol 15 (2) ◽

pp. 239 ◽

Cited By ~ 8

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.

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Gas-blood PCO2 gradients during avian gas exchange

Journal of Applied Physiology ◽

10.1152/jappl.1975.39.3.405 ◽

1975 ◽

Vol 39 (3) ◽

pp. 405-410 ◽

Cited By ~ 20

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.

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