Photosynthetic Performance of Two Closely Related Umbilicaria Species in Central Spain: Temperature as a Key Factor

1997 ◽  
Vol 29 (1) ◽  
pp. 67-82 ◽  
Author(s):  
L. G. Sancho ◽  
B. Schroeter ◽  
F. Valladares
Keyword(s):  
Water Content ◽  
Dark Respiration ◽  
Net Photosynthesis ◽  
Dry Weight ◽  
Distribution Patterns ◽  
Photon Flux ◽  
Photosynthetic Response ◽  
Central Spain ◽  
Natural Conditions ◽  
Thallus Water Content

AbstractNet photosynthesis (NP) and dark respiration (DR) of thalli of the lichen species Umbilicaria grisea and U. freyi growing together in the same habitat the Sierra de Guadarrama, central Spain, were measured under controlled conditions in the laboratory and under natural conditions in the field over a range of photosynthetic photon flux densities (PPFD), thallus temperatures and thallus water contents. Laboratory experiments revealed that the photosynthetic response to PPFD at optimum thallus water content is very similar in both species. The light compensation points of NP increased from PPFD of c. 20 µmol m−2 s−1 at 0°C up to c. 100 µmol m−2 s−1 PPFD at 25°C. In both species light saturation was not reached up to 700 µmol m−2 s−1 PPFD except at 0°C. By contrast, the temperature dependence of CO2 gas exchange differed substantially between U. grisea and U. freyi. Both species gave significant rates at 0°C. Optimal temperatures of NP were always higher in U. grisea at various PPFD levels if the samples were kept at optimal thallus water content. NP showed maximal rates at 95% dw in U. grisea and 110% dw in U. freyi respectively. In U. grisea a much stronger depression of NP was observed with only 5% of maximal NP reached at 180% dw. At all PPFD and temperature combinations U. freyi showed higher rates of NP and more negative rates of DR if calculated on a dry weight basis. This was also true under natural conditions at the same site, when U. freyi was always more productive than U. grisea. The differences in the photosynthetic response to temperature between both species correlated well with the different distribution patterns of both species. The possibility of genetic control of the physiological performance of these species and its influence on their distribution patterns and autecology is discussed.

scholarly journals Photosynthetic responses of three common mosses from continental Antarctica

2005 ◽  
Vol 17 (3) ◽  
pp. 341-352 ◽  
Author(s):  
STEFAN PANNEWITZ ◽  
T.G. ALLAN GREEN ◽  
KADMIEL MAYSEK ◽  
MARK SCHLENSOG ◽  
ROD SEPPELT ◽  
...  
Keyword(s):  
Climate Change ◽  
Water Content ◽  
Dark Respiration ◽  
Temperature Response ◽  
Environmental Parameters ◽  
Net Photosynthesis ◽  
Photon Flux ◽  
Terrestrial Vegetation ◽  
Moss Species ◽  
Victoria Land

Predicting the effects of climate change on Antarctic terrestrial vegetation requires a better knowledge of the ecophysiology of common moss species. In this paper we provide a comprehensive matrix for photosynthesis and major environmental parameters for three dominant Antarctic moss species (Bryum subrotundifolium, B. pseudotriquetrum and Ceratodon purpureus). Using locations in southern Victoria Land, (Granite Harbour, 77°S) and northern Victoria Land (Cape Hallett, 72°S) we determined the responses of net photosynthesis and dark respiration to thallus water content, thallus temperature, photosynthetic photon flux densities and CO2 concentration over several summer seasons. The studies also included microclimate recordings at all sites where the research was carried out in field laboratories. Plant temperature was influenced predominantly by the water regime at the site with dry mosses being warmer. Optimal temperatures for net photosynthesis were 13.7°C, 12.0°C and 6.6°C for B. subrotundifolium, B. pseudotriquetrum and C. purpureus, respectively and fall within the known range for Antarctic mosses. Maximal net photosynthesis at 10°C ranked as B. subrotundifolium > B. pseudotriquetrum > C. purpureus. Net photosynthesis was strongly depressed at subzero temperatures but was substantial at 0°C. Net photosynthesis of the mosses was not saturated by light at optimal water content and thallus temperature. Response of net photosynthesis to increase in water content was as expected for mosses although B. subrotundifolium showed a large depression (60%) at the highest hydrations. Net photosynthesis of both B. subrotundifolium and B. pseudotriquetrum showed a large response to increase in CO2 concentration and this rose with increase in temperature; saturation was not reached for B. pseudotriquetrum at 20°C. There was a high level of variability for species at the same sites in different years and between different locations. This was substantial enough to make prediction of the effects of climate change very difficult at the moment.

Photosynthesis and dark respiration of black spruce cuttings during rooting in response to light and temperature

1993 ◽  
Vol 23 (6) ◽  
pp. 1150-1155 ◽  
Author(s):  
De Yue ◽  
Hank A. Margolis
Keyword(s):  
Black Spruce ◽  
Dark Respiration ◽  
Net Photosynthesis ◽  
Dry Weight ◽  
Experimental Period ◽  
Photon Flux ◽  
Photosynthetic Rates ◽  
Physiological Quality ◽  
Use Efficiency ◽  
Total Dry Weight

Photosynthesis and dark respiration of semihardened black spruce cuttings (Piceamariana (Mill.) B.S.P.) were periodically measured at a range of light intensities at 10, 15, 20, 25, and 30 °C over an 8-week period in rooting chambers and for 4 additional weeks after the cuttings were transferred to a greenhouse. Increases in the total dry weight of the cuttings over the experimental period were due exclusively to increases in root biomass. The light-saturated photosynthetic rates at 20 °C decreased from 3.8 to 2.2 μmol CO2•m−2•s−1 during the 8 weeks in the rooting chamber. At 15 °C, the light-saturated photosynthetic rate was about 2 μmol CO2•m−2•s−1 and no significant change was observed during the experimental period. Maximum photosynthetic rates were generally attained at photosynthetic photon flux densities (PPFD) of 200–300 μmol•m−2•s−1 At the range of PPFD generally used in rooting chambers (0–50 μmol•m−2•s−1), the light use efficiency of cuttings (net photosynthesis per cutting per PPFD) was greatest at 15 °C. Furthermore, the light compensation point was lowest at 15 °C. The effect of light intensity and temperature on the photosynthesis and dark respiration of cuttings was modelled to predict the carbon balance of cuttings under different conditions of PPFD and temperature. This model should be useful in determining an appropriate set of environmental conditions to use inside rooting chambers and thus improve the overall physiological quality of this type of vegetatively propagated planting stock. The modelling approach described in this study could prove useful for the production of other conifer species by rooted cuttings even when it is conducted using other methods of cultivation (e.g., cold-frames or greenhouses).

Ecological significance of net photosynthesis activation by water vapour uptake in Ramalina capitata from rain-protected habitats in central Spain

2002 ◽  
Vol 34 (5) ◽  
pp. 403-413 ◽  
Author(s):  
Ana Pintado ◽  
Leopoldo G. Sancho
Keyword(s):  
Water Content ◽  
Water Vapour ◽  
Liquid Water ◽  
Net Photosynthesis ◽  
Dry Weight ◽  
Central Spain ◽  
Photosynthetic Rates ◽  
Positive Balance ◽  
Water Vapour Uptake ◽  
Water Contents

AbstractThe reactivation of net photosynthesis and dark respiration from water vapour and from liquid water in the lichen Ramalina capitata var. protecta (H. Magn.) Nimis from sheltered habitats in Central Spain was investigated. CO2 gas-exchange response and thallus water content were measured in the laboratory as dry thalli were allowed to equilibrate by water vapour uptake under different relative humidities, and as saturated thalli dried. Water content of thalli from different habitats was also measured in the field during rainfall. The results show that the lichen is very efficient in using water vapour from the air for photosynthesis. Net photosynthetic rates were measured at very low water potentials (up to – 26-9 Megapascal) with water contents of the thalli below 30% dry weight. Maximum net photosynthetic rates measured after water vapour uptake were in some cases similar to those obtained after hydration by liquid water, while respiration rates were always lower after water vapour uptake, indicating a relatively larger activation of the photobiont. Moreover, photosynthetic rates at thallus water contents below 60% dry weight were higher when hydration was achieved through water vapour uptake than with liquid water. Field measurements had shown that this lichen reached water contents through water vapour absorption of 40% dry weight that would allow a positive balance of CO2 uptake. Possible ecological implications of differences in photosynthetic activation depending on the water source are discussed in terms of the carbon gain under natural conditions of this ombrophobous lichen.

Comparative CO2 exchange patterns in mosses from two tundra habitats at Barrow, Alaska

1976 ◽  
Vol 54 (12) ◽  
pp. 1355-1369 ◽  
Author(s):  
Walter C. Oechel ◽  
Nigel J. Collins
Keyword(s):  
Light Intensity ◽  
Water Content ◽  
Dark Respiration ◽  
Net Photosynthesis ◽  
Dry Weight ◽  
Co2 Exchange ◽  
Polar Regions ◽  
Light Intensities ◽  
Matter Production ◽  
Exchange Patterns

The effects of variation in light intensity, temperature, and water content on rates of net photosynthesis and dark respiration have been investigated in two common tundra mosses, Polytrichum alpinum from drier habitats and Calliergon sarmentosum from wetter habitats at Barrow, Alaska. Optimum temperatures for net photosynthesis of 10–15 °C for both species and saturating light intensities (photosynthetically active radiation (PhAR), 400–700 nm) of about 0.12 cal cm−2 min−1 for P. alpinum and 0.15 cal cm−2 min−1 for C. sarmentosum correlate well with measurements of light intensity and moss tissue temperatures made over the season at the collection site. It is suggested that depressions in net photosynthetic rates around midday might be caused by supraoptimal temperatures and possibly supraoptimal light intensities. Calliergon sarmentosum, a semiaquatic species required a higher water content (about 450% dry weight) than P. alpinum (about 200%) to reach maximal rates of net photosynthesis. Mean maximal rates of net photosynthesis ranged from about 2.6 to 4.4 mg CO2 g−1 dry weight h−1 for P. alpinum and from about 1.5 to 3.0 mg CO2 g−1 dry weight h−1 for C. sarmentosum. Predictions of net annual production have been made for both species. Predicted levels of 171 g C m−2 per 50-day season for C. sarmentosum compare well with results obtained for species of similar growth form elsewhere in polar regions. For P. alpinum the predicted level of 38.5 g C m−2 per 50-day season compares with observed dry matter production at the same site of 43 g m−2 per season.

Productivity of Vegetable Crops in a Region of High Solar Input. III. Carbon Balance of Potato Crops

1974 ◽  
Vol 1 (2) ◽  
pp. 283 ◽  
Author(s):  
PJM Sale
Keyword(s):  
Carbon Balance ◽  
Dark Respiration ◽  
Net Photosynthesis ◽  
Dry Weight ◽  
Gas Analysis ◽  
Co2 Uptake ◽  
Co2 Efflux ◽  
Vegetable Crops ◽  
Weight Changes ◽  
Potato Crops

The carbon balance of potato crops has been studied by measuring canopy net photosynthesis and dark respiration losses with a field assimilation chamber and semi-closed gas analysis system. Results are given for the latter part of growth in both a spring-planted and a summer-planted crop. Net CO2 uptake increased with solar input to reach 35–40mg dm-2 (ground area) h-1 at 400–450 W m-2, but light saturation then occurred and little or no further uptake resulted from increases in solar input up to 1000 W m-2. This supports the previous conclusion that net photosynthesis in the potato is determined by the size of the 'sink' provided by the developing tubers. The imposed experimental variables of reduced solar input (21 and 34% shade) and soil moisture were found not to affect the relation between solar input and CO2 uptake, and the effect of chamber temperature was also very small. Dark respiration rates of the canopy were markedly sensitive to temperature, and also to the solar input prior to measurement. Respiration from the below-ground plant parts accounted for a considerable part of the total plant respiration. In all, 15–20 % of the net assimilation during daylight hours was lost by night respiration. There was little variation in CO2 efflux from uncropped soil during the experiments. Dry weight changes calculated from the gasometric measurements were in accordance with those found from previous growth analysis. * Part II, Aust. J. Agric. Res., 1973, 24, 751–62.

The ecology of Ramalina menziesii. VI. Laboratory responses of net CO2 exchange to moisture, temperature, and light

1987 ◽  
Vol 65 (1) ◽  
pp. 182-191 ◽  
Author(s):  
U. Matthes-Sears ◽  
T. H. Nash III ◽  
D. W. Larson
Keyword(s):  
Dark Respiration ◽  
Net Photosynthesis ◽  
Co2 Exchange ◽  
Response Curves ◽  
Central California ◽  
Photosynthetic Rates ◽  
Chlorophyll Contents ◽  
The Mean ◽  
The Difference ◽  
Thallus Water Content

The response of net CO2 exchange to thallus water content, thallus temperature, and photosynthetically active radiation was measured in the laboratory for two morphologically different forms of Ramalina menziesii collected from a coastal and an inland habitat in central California. Equations describing the response curves are fitted to the data and compared statistically for the two sites during two seasons. Significant differences were present for all responses both in summer and winter but were more pronounced for net photosynthesis than for dark respiration. The main differences between the two forms were in the absolute rates of net photosynthesis; a maximum of 6.2 was measured for the inland form but only 3.6 mg∙g−1∙h−1 for the coastal form. Chlorophyll contents were also different between the two forms, indicating that chlorophyll is the likely cause for the difference in net photosynthetic rates. Net photosynthetic rates were higher at low temperatures during winter than during summer, but otherwise seasonal variations in the gas exchange responses were relatively minor. Both forms of the lichen are light saturated at quantum fluxes greater than 200 μE∙m−2∙s−1. Both show an optimum temperature for maximum CO2 exchange at 25 °C, well above the mean operating temperature of R. menziesii in the field.

scholarly journals PHOTOSYNTHESIS, RESPIRATION, AND CARBON COST OF DEVELOPING RABBITEYE BLUEBERRY FRUIT

HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1165g-1166
Author(s):  
Keith Birkhold ◽  
Rebecca Darnell ◽  
Karen Koch
Keyword(s):  
Weight Gain ◽  
Fruit Development ◽  
Dark Respiration ◽  
Net Photosynthesis ◽  
Dry Weight ◽  
Total Carbon ◽  
Vaccinium Ashei ◽  
Gross Photosynthesis ◽  
Carbon Cost ◽  
Fruit Photosynthesis

Carbon exchange and content of blueberry (Vaccinium ashei) fruit were measured from anthesis through fruit ripening in order to determine the amount of imported carbon required for fruit development. Net photosynthesis occurred in blueberry fruit from petal fall through color break. During this time, gross photosynthesis of fruit decreased from 30.1 μmol CO2·g fw-1·hr-1 to 4.8 μmol CO2·g fw-1·hr-1, and dark respiration decreased from 14.3 μmol CO2·g fw-1·hr-1 to 4.6 μmol CO2·g fw-1·hr-1. After color break, the photosynthetic rate fell to zero, and the respiration rate increased to 8.0 μmol CO2·g fw-1·hr-1, before decreasing. Preliminary data suggest that fruit photosynthesis contributes 11% of the total carbon required (dry weight gain + respiratory loss) during fruit development however, it supplies 50% of the total carbon required during the first 5 days after petal fall. This contribution of carbon from fruit photosynthesis may be critical in initial fruit development since the current season's vegetative growth is not yet providing carbohydrates.

Genotypic Variation in Light and Temperature Response of Photosynthesis in Nothofagus solandri Var. cliffortioides and N. menziesii

1996 ◽  
Vol 23 (4) ◽  
pp. 421 ◽  
Author(s):  
OJ Sun ◽  
GB Sweet
Keyword(s):  
New Zealand ◽  
Dark Respiration ◽  
Genotypic Variation ◽  
Temperature Response ◽  
Light Response ◽  
Net Photosynthesis ◽  
Photosynthetic Photon Flux Density ◽  
Ecosystem Dynamics ◽  
Photon Flux ◽  
Photon Flux Density

Responses of photosynthesis to light and temperature were studied in two Nothofagus species native to New Zealand: N. solandri var. cliffortioides (Hook. f.) Poole and N. menziesii (Hook. f.) Oerst.. Measurements of leaf photosynthesis were made in a controlled environment growth chamber at photosynthetic photon flux density between 0 and 700 μmol m-2 s-1 with temperatures set for 10, 20 and 25�C, on seedlings previously grown in a glasshouse from seed of three different origins. In both species, pronounced intraspecific variation was shown in dark respiration, light compensation point and light-saturated net photosynthesis (Amax). Seedlings of N. solandri showed higher dark respiration and light compensation levels than N. menziesii seedlings, but the two species did not differ in Amax. Change in temperature resulted in significant change in the response of photosynthesis to light in both N. solandri and N. menziesii. The differences between N. solandri and N. menziesii in light response of photosynthesis are discussed in terms of ecosystem dynamics of Nothofagus forests in New Zealand.

Photosynthetic light and temperature responses of Eucalyptus cloeziana and Eucalyptus argophloia

2003 ◽  
Vol 51 (5) ◽  
pp. 573 ◽  
Author(s):  
Michael R. Ngugi ◽  
Mark A. Hunt ◽  
David Doley ◽  
Paul Ryan ◽  
Peter J. Dart
Keyword(s):  
Quantum Yield ◽  
Dark Respiration ◽  
Temperature Response ◽  
Net Photosynthesis ◽  
Photosynthetic Photon Flux Density ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Response Curves ◽  
Growth Environment ◽  
Eucalyptus Cloeziana

Acclimation of gas exchange to temperature and light was determined in 18-month-old plants of humid coastal (Gympie) and dry inland (Hungry Hills) provenances of Eucalyptus cloeziana F.Muell., and in those of a dry inland provenance of Eucalyptus argophloia Blakely. Plants were acclimated at day/night temperatures of 18/13, 23/18, 28/23 and 33/28�C in controlled-temperature glasshouses for 4 months. Light and temperature response curves were measured at the beginning and end of the acclimation period. There were no significant differences in the shape and quantum-yield parameters among provenances at 23, 28 and 33�C day temperatures. Quantum yield [μmol CO2 μmol–1 photosynthetic photon flux density (PPFD)] ranged from 0.04 to 0.06 and the light response shape parameter ranged from 0.53 to 0.78. Similarly, no consistent trends in the rate of dark respiration for plants of each provenance were identified at the four growth temperatures. Average values of dark respiration for the plants of the three provenances ranged from 0.61 to 1.86 μmol m–2 s–1. The optimum temperatures for net photosynthesis increased from 23 to 32�C for the humid- and from 25 to 33�C for the dry-provenance E. cloeziana and from 21 to 33�C for E. argophloia as daytime temperature of the growth environment increased from 18 to 33�C. These results have implications in predicting survival and productivity of E. cloeziana and E. argophloia in areas outside their natural distribution.

Circadian rhythms of dark respiration, flowering, net photosynthesis, chlorophyll content, and dry weight changes in Chenopodium rubrum

1972 ◽  
Vol 50 (11) ◽  
pp. 2219-2226 ◽  
Author(s):  
Ah-Sing Chia-Looi ◽  
Bruce G. Gumming
Keyword(s):  
Circadian Rhythms ◽  
Chlorophyll Content ◽  
Dark Respiration ◽  
Net Photosynthesis ◽  
Dry Weight ◽  
Chenopodium Rubrum ◽  
Weight Changes ◽  
Physiological Processes ◽  
Dark Fixation ◽  
Relationship Of

There are circadian rhythmic changes in dark respiration, net photosynthesis, chlorophyll content, and dry weight in Chenopodium rubrum, ecotype 60°47′ N, 137°32′ W. The rhythm in dark respiration has a period of about 27 h and its phasing is quite closely correlated with the rhythm in flowering response, which has a period of about 30 h. A close similarity in the periodicity (21 h) and phasing of the rhythms in net photosynthesis and chlorophyll content suggests that the photosynthetic rhythm may be partly attributed to rhythmic changes in chlorophyll content. The rhythmic changes in dry weight, with a period of 18 h, could be due to a rhythm in dark fixation of carbon dioxide. The possible relationship of rhythmicity in these processes to other circadian rhythms that occur in C. rubrum is discussed. The concurrent existence of various rhythms in biochemical and physiological processes that differ in period and phase within a single ecotype of C. rubrum clearly reflects the possible involvement of metabolic activity in circadian rhythms.

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