Studies on lichen-dominated systems. XIV. The comparative ecology of Alectoria nitidula and Cladina alpestris

1975 ◽  
Vol 53 (22) ◽  
pp. 2608-2613 ◽  
Author(s):  
K. A. Kershaw
Keyword(s):  
Net Photosynthesis ◽  
The Other ◽  
Beach Ridge ◽  
Temperature Optimum ◽  
Comparative Ecology ◽  
Respiration Rates ◽  
Photosynthesis And Respiration

The response of net photosynthesis and respiration in Cladina alpestris and Alectoria nitidula, at 0 and 150 μeinsteins m−2 s−1, 5, 10, 15, 20, 25, and 30 °C, and at all thallus moisture levels, is described. The two species have markedly contrasting responses, which correlates very well with their ecology at East Pen Island. Cladina alpestris is shown to occur in two physiological forms: one is restricted to beach ridge summits and the other is restricted to the lower slopes. The physiology of these two forms adapts them to either the cool, dry, ridge crests or the warmer, moister, ridge slopes. Marked acclimation of the temperature optimum of net photosynthesis in Alectoria nitidula is shown to occur between August and December. This is an acclimation of the photosynthetic mechanism of the algal component since respiration rates remain constant. Alectoria nitidula is shown to further acclimate to warm temperatures under air-dried conditions in the laboratory.

Photosynthetic response to growth temperature and CO2 enrichment in two species of C4 grasses

1985 ◽  
Vol 63 (3) ◽  
pp. 483-487 ◽  
Author(s):  
Catherine Potvin ◽  
Boyd R. Strain
Keyword(s):  
North Carolina ◽  
Growth Temperature ◽  
Dark Respiration ◽  
Co2 Enrichment ◽  
Net Photosynthesis ◽  
C4 Grasses ◽  
Eleusine Indica ◽  
Respiration Rates ◽  
Acclimation Potential ◽  
Photosynthesis And Respiration

Plants of Echinochloa crus-galli from Québec, North Carolina, and Mississippi and of Eleusine indica from Mississippi were grown under three thermoperiods (28:22, 24:18, 21:15 °C) and two atmospheric CO2 concentrations (350 and 675 μL ∙ L−1). CO2 enrichment induced an increase in net photosynthesis and in dark respiration for all populations. Neither conductance, transpiration, nor the transpiration/photosynthesis ratio were affected by CO2 enrichment. Plants showed higher photosynthetic and dark respiration rates when grown in warm regimes. Stomatal conductance did not vary with growth temperature. Cool-adapted plants from Québec maintained the overall highest net photosynthesis and respiration. Plants originating from warm areas had a weaker acclimation potential to low temperature than those from cool environments.

Effects of pCO2 on photosynthesis and respiration of tropical scleractinian corals and calcified algae

2016 ◽  
Vol 74 (4) ◽  
pp. 1092-1102 ◽  
Author(s):  
S. Comeau ◽  
R. C. Carpenter ◽  
P. J. Edmunds
Keyword(s):  
Dark Respiration ◽  
Net Photosynthesis ◽  
French Polynesia ◽  
Published Data ◽  
Experimental Conditions ◽  
Gross Photosynthesis ◽  
Functional Relationships ◽  
Respiration Rates ◽  
Photosynthesis And Respiration

The effects of ocean acidification (OA) on coral reefs have been studied thoroughly with a focus on the response of calcification of corals and calcified algae. However, there are still large gaps in our knowledge of the effects of OA on photosynthesis and respiration of these organisms. Comparisons among species and determination of the functional relationships between pCO2 and either photosynthesis or respiration are difficult using previously published data, because experimental conditions typically vary widely between studies. Here, we tested the response of net photosynthesis, gross photosynthesis, dark respiration, and light-enhanced dark respiration (LEDR) of eight coral taxa and seven calcified alga taxa to six different pCO2 levels (from 280 to 2000 µatm). Organisms were maintained during 7–10 days incubations in identical conditions of light, temperature, and pCO2 to facilitate comparisons among species. Net photosynthesis was not affected by pCO2 in seven of eight corals or any of the algae; gross photosynthesis did not respond to pCO2 in six coral taxa and six algal taxa; dark respiration also was unaffected by pCO2 in six coral and six algae; and LEDR did not respond to pCO2 in any of the tested species. Overall, our results show that pCO2 levels up to 2000 µatm likely will not fertilize photosynthesis or modify respiration rates of most of the main calcifiers on the back reef of Moorea, French Polynesia.

Carbon balance in relation to drying in four epiphytic mosses growing in different vertical ranges

1979 ◽  
Vol 57 (19) ◽  
pp. 1994-1998 ◽  
Author(s):  
Peter L. Tobiessen ◽  
Nancy G. Slack ◽  
Keith A. Mott
Keyword(s):  
Water Potential ◽  
Water Content ◽  
Carbon Balance ◽  
The Other ◽  
Moss Species ◽  
Relationship Of ◽  
The Relationship ◽  
Neckera Pennata ◽  
Lower Water Content ◽  
Photosynthesis And Respiration

The response of photosynthesis and respiration to drying was measured in four species of epiphytic mosses, Ulota crispa (Hedw.) Brid., Neckera pennata Hedw., Anomodon rugellii (C. Mull.) Keissl., and Plagiomnium cuspidatum (Hedw.) T. Kop., from habitats along a desiccation gradient. There was little difference among the mosses in these responses. The relationship of water content to water potential did differ among the mosses, with Plagiomnium, the facultative epiphyte, showing a typical response of more mesic species and the other three showing a more xeric response, i.e., water potential does not begin to fall steeply until a lower water content is reached in Ulota, Neckera, and Anomodon. Both photosynthesis and respiration in all four moss species were quite sensitive to moderate water stress.

Isolation and Characterization of a Chlorogenic Acid Esterase from Aspergillus niger

1980 ◽  
Vol 35 (3-4) ◽  
pp. 209-212 ◽  
Author(s):  
B. Schöbel ◽  
W. Pollmann
Keyword(s):  
Enzyme Activity ◽  
Chlorogenic Acid ◽  
Divalent Cations ◽  
Hydrolysis Product ◽  
The Other ◽  
Temperature Optimum ◽  
Pig Liver ◽  
Isolation And Characterization

Abstract The isolation and characterization of a specific chlorogenic acid esterase is described. The enzyme activity is measured by determination of the hydrolysis product caffeic acid. The enzyme had been concentrated by means of ultrafiltration and column-chromatography. The pH- and temperature optimum were 6.5 and 45 °C respectively. Divalent cations were not required for the enzyme activity. As other esterases, this enzyme is inhibited by di-isopropyl-phosphorofluoridate. The Km-value is 0.70 mᴍ chlorogenic acid, the molecular weight 240000. The described enzyme is specific for chlorogenic acid. On the other hand a typical unspecific esterase like the pig liver esterases does not split chloro­genic acid. The isoelectric focusing reveals several isoenzymes of chlorogenase within a pI-range of 4.0-4.5.

Altitudinal Variation in the Photosynthetic Characteristics of Snow Gum, Eucalyptus pauciflora Sieb. Ex Spreng. II. Effects of Growth Temperature Under Controlled Conditions

1977 ◽  
Vol 4 (2) ◽  
pp. 289 ◽  
Author(s):  
RO Slatyer ◽  
PJ Ferrar
Keyword(s):  
Gas Phase ◽  
Growth Temperature ◽  
Physiological Responses ◽  
Woody Species ◽  
Net Photosynthesis ◽  
Photosynthetic Characteristics ◽  
Temperature Optimum ◽  
Altitudinal Variation ◽  
Intracellular Resistance ◽  
Photosynthetic Responses

The photosynthetic responses of three altitudinal populations of snow gum, E. pauciflora Sieb. ex Spreng., were examined on material grown at a range of day/night temperatures from 8/4 to 33/28°C. The pattern of the photosynthetic responses to growth temperature was generally similar for all populations but the material from the lowest-elevation, warmest, site showed the highest temperature optimum and significantly higher rates of net photosynthesis at the highest growth temperature. In a corresponding way, the material from the highest-elevation, coldest, site showed the lowest temperature optimum, and significantly higher rates of net photosynthesis at the lowest growth temperature. This pattern, also reflected in the responses of rI, the intracellular resistance, and rI, the gas-phase resistance, supported the view that E. pauciflora shows continuous variation in physiological responses through its altitudinal range. The peak values of net photosynthesis were high for all populations, but were greatest, 81 ng cm-2 s-1, in the lowest elevation material and decreased to 72 ng cm-2 s-1 in the highest-elevation material. Corresponding values of rI ranged from 2.5 - 3.0 s cm-1, and for rI from 2.4 - 3.3 s cm-1. These levels compare favourably with levels reported for other woody species.

Photosynthesis and respiration decline with light intensity in dominant and suppressed Eucalyptus globulus canopies

2008 ◽  
Vol 35 (6) ◽  
pp. 439 ◽  
Author(s):  
A. P. O'Grady ◽  
D. Worledge ◽  
A. Wilkinson ◽  
M. Battaglia
Keyword(s):  
Eucalyptus Globulus ◽  
Dark Respiration ◽  
Light Availability ◽  
Structural Complexity ◽  
Leaf Nitrogen ◽  
Leaf Nitrogen Content ◽  
Area Index ◽  
Respiration Rates ◽  
Leaf Dark Respiration ◽  
Photosynthesis And Respiration

Within canopy gradients in light-saturated photosynthesis (Amax), foliar nitrogen ([N]area) and leaf dark respiration (R15) were studied in the canopies of dominant and suppressed trees within an even-aged (4-year-old) Eucalyptus globulus (Labill) stand in southern Tasmania. Despite being an even-aged stand growing in a relatively uniform environment with respect to nutrient and water availability, the stand exhibited considerable structural complexity. Diameter at 1.3 m ranged between 3 cm and 21 cm, trees average 12 m height and stand leaf area index was ~6 m2 m–2 leading to strong gradients in light availability. We were interested in understanding the processes governing canopy production in trees of contrasting dominance classes. Vertical gradients in photosynthesis and foliar respiration were studied within the canopies of dominant and suppressed trees during 2006 and 2007. Amax varied from ~18 μmol m–2 s–1 in the upper canopy to 3 μmol m–2 s–1 at lower canopy positions. On average, Amax were higher in the dominant trees than in the suppressed trees. However, at any given height, Amax were similar in suppressed and dominant trees and were strongly related to leaf nitrogen content. Dark respiration varied from ~1.4 μmol m–2 s–1 in the upper canopy to 0.2 μmol m–2 s–1 in the lower canopy positions. In contrast to the patterns for Amax, dark respiration rates in the suppressed trees were higher than dominant trees at similar canopy positions. Respiration rates were also strongly related to [N]area and to Amax.

Responses of Zebu, Jersey, and Zebu X Jersey crossbred heifers to rising temperature, with particular reference to sweating

1962 ◽  
Vol 13 (1) ◽  
pp. 165 ◽  
Author(s):  
TE Allen
Keyword(s):  
Skin Temperature ◽  
Air Temperature ◽  
Rectal Temperature ◽  
Temperature Regime ◽  
Linear Increase ◽  
The Other ◽  
Sweating Rate ◽  
Respiration Rates ◽  
Breed Differences ◽  
Skin Temperatures

Zebu, Jersey, and Zebu x Jersey crossbred heifers were subjected to a rising temperature regime over the range 65 to 105°F. Sweating rates, respiration rates, skin temperatures, and rectal temperatures were measured. All breeds showed similar responses in skin temperature and rectal temperature to increase in air temperature. The increase in skin temperature was approximately linear with rise in air temperature. Rectal temperature did not commence to rise until an air temperature of 90°F and a skin temperature of 98° was reached. Breed differences in sweating and respiratory rates with increase in air and skin temperature were observed. The Jersey heifers showed an early and almost linear increase in sweating rate with rise in air and skin temperature, whereas the sweating rate of the Zebu heifers did not increase until air temperature had risen to at least 85°F and skin temperature to 95°. Two crossbreds began to increase their sweating rates at temperatures intermediate between those recorded for Zebus arid Jerseys. The remaining two behaved similarly to Jerseys. All three breeds showed similar maximum sweating rates in response to this rising temperature regime. The respiratory rate of' the Jerseys was higher than that of the Zebus at all temperatures, and particularly at high temperatures. Crossbreds respired at rates comparable to the Jerseys until an air temperature of 90°F and a skin temperature of 97°F were exceeded, when their respiration rates became intermediate between the other two breeds. The significance of these differences is discussed.

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