Studies on lichen-dominated systems. XVI. Comparative patterns of net CO2 exchange in Cetraria nivalis and Alectoria ochroleuca collected from a raised-beach ridge

1975 ◽  
Vol 53 (23) ◽  
pp. 2884-2892 ◽  
Author(s):  
D. W. Larson ◽  
K. A. Kershaw
Keyword(s):  
Species Distribution ◽  
Net Photosynthesis ◽  
Co2 Exchange ◽  
Physiological Data ◽  
Seasonal Patterns ◽  
Beach Ridge ◽  
Bottom Position ◽  
Intraspecific Difference ◽  
Seasonal Acclimation ◽  
Data Matrices

Seasonal patterns of net photosynthesis in Cetraria nivalis that was collected from the top and bottom positions of a raised-beach ridge were examined in relation to those for Alectoria ochroleuca from the same site. While seasonal acclimation is pronounced in C. nivalis to an extent equal to that found in A. ochroleuca, C. nivalis showed significant intraspecific difference in these patterns. Cetraria nivalis that was collected from the bottom position of the beach ridge is more active metabolically than the ridge-top collections. Cetraria nivalis is most abundant on the lower slopes of these ridges. A comparison of the physiological data matrices for both ridge-top and ridge-bottom collections of A. ochroleuca and C. nivalis partly explains the patterns of species distribution that are observed in the field.

Studies on lichen-dominated systems. XIII. Seasonal and geographical variation of net CO2 exchange of Alectoria ochroleuca

1975 ◽  
Vol 53 (22) ◽  
pp. 2598-2607 ◽  
Author(s):  
D. W. Larson ◽  
K. A. Kershaw
Keyword(s):  
Light Intensity ◽  
Intraspecific Variation ◽  
Seasonal Changes ◽  
Net Photosynthesis ◽  
Co2 Exchange ◽  
Ecological Significance ◽  
Beach Ridge ◽  
Exchange Method ◽  
Geographical Locations ◽  
Seasonal Acclimation

By using a new gas-exchange method, the seasonal changes in net photosynthetic rates of Alectoria ochroleuca were examined in relation to thallus moisture content, thallus temperature, and light intensity. These experiments were run using samples collected from both the top and bottom positions of a raised-beach ridge and showed very little intraspecific variation. Collections made from other geographical locations, however, showed that considerable intraspecific variation was possible within this species.At the Pen Island site, A. ochroleuca shows patterns of net photosynthesis adapted to the xeric ridge-top environments on which it is most abundant.Rapid seasonal acclimation to temperature and changes in the response to light intensity were found for both ridge-top and ridge-bottom collections of A. ochroleuca. The ecological significance of these findings is discussed.

Influence of temperature on net CO2 exchange in roses

1991 ◽  
Vol 71 (1) ◽  
pp. 235-243 ◽  
Author(s):  
J. Jiao ◽  
M. J. Tsujita ◽  
B. Grodzinski
Keyword(s):  
Dark Respiration ◽  
Net Photosynthesis ◽  
Co2 Exchange ◽  
Effect Of Temperature ◽  
Flower Bud ◽  
Temperature Range ◽  
Whole Plant ◽  
Optimal Temperature Range ◽  
Influence Of Temperature On ◽  
Whole Plants

The effect of temperature on net CO2 exchange of source and sink tissues of the flowering shoots and of whole plants was examined using single-stemmed Samantha roses. At all stages of shoot development, the optimal temperature range for whole-plant carbon (C) gain at saturating irradiance and ambient CO2 level was between 20° and 25 °C, narrower than the temperature range for optimal leaf net photosynthesis. Dark respiration increased more dramatically than photosynthesis with temperatures between 15 and 35 °C. At 25 °C, C loss due to respiration from the flower bud at colour bud stage accounted for 45% of the C loss of the flowering shoot. At low irradiance levels (e.g. 200 μmol m−2 s−1) whole-plant net photosynthesis was greater at 16° than at 22 °C because of a greater reduction in respiration. Lowering the night temperature from 27 to 17 °C also increased daily C gain due to a reduction in the C lost at night. Whole-plant net photosynthesis of plants grown and measured at enriched (1000 ± 100 μL L−1) CO2 was greater than that of plants grown and measured at ambient (350 ± 50 μL L−1) level at temperatures between 15° and 35 °C. Furthermore, the optimal temperatures for whole-plant net photosynthesis in CO2 enrichment was higher than at ambient CO2 level. Key words: Dark respiration, net photosynthesis, Rosa hybrida, temperature

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 Uso da subirrigação para imposição de estresse hídrico em sistema semi-contínuo para medição de CO2

2015 ◽  
Vol 21 (2) ◽  
pp. 235 ◽  
Author(s):  
Rhuanito Soranz Ferrarezi ◽  
Marc W. Van Iersel ◽  
Roberto Testezlaf
Keyword(s):  
Soil Moisture ◽  
Water Stress ◽  
Plant Growth ◽  
Net Photosynthesis ◽  
Dry Mass ◽  
Co2 Exchange ◽  
Carbon Gain ◽  
Growth Responses ◽  
Shoot Height ◽  
Soil Moisture Sensors

The objectives of this work were to evaluate the effects of distinct moisture contents to trigger subirrigation on salvia photosynthesis and plant growth, and to verify the feasibility of subirrigation use in water stress imposition research in this crop. We evaluated two substrate volumetric water contents (VWC) as treatments (0.2 and 0.4 m3 m-3) to trigger subirrigation, with 4 replications. Each replication was composed of 10 plants. An automated semi-continuous multi-chamber crop CO2-exchange system was used, with capacitance soil moisture sensors for continuous moisture monitoring. Manual subirrigation with nutrient solution was performed when VWC dropped below the thresholds. In both treatments, the values of net photosynthesis, daily carbon gain and carbon use efficiency reduced over time, from 2 to 1.1 μmol s-1 from 2.2 to 1 μmol d-1 from 0.7 to 0.45 mol mol-1, respectively, in both soil moisture treatments. Total shoot dry mass (p=0.0129), shoot height in the tip of the highest flower (p<0.0001) and total leaf area (p=0.0007) were statistically higher at 0.4 m3 m-3 treatment. The subirrigation system was not efficient to impose water stress, due to excessive variation on VWC values after each irrigation event in both treatments. Higher soil moisture promoted positive plant growth responses in salvia cultivated by subirrigation.

scholarly journals Spiders of the Udmurt Republic, Russia

2021 ◽  
Vol 9 ◽  
Author(s):  
Artëm Sozontov
Keyword(s):  
Species Distribution ◽  
Ad Hoc ◽  
Habitat Preferences ◽  
Seasonal Patterns ◽  
Natural Zones ◽  
Udmurt Republic ◽  
The Republic ◽  
Existing Data ◽  
Regional Fauna

The long-term project "Spiders of the Udmurt Republic" (2007–2018) aimed to research spiders' regional fauna and zoogeography, diversity (including spatial and seasonal patterns) and habitat preferences. We performed the collection of spiders in all natural zones of the republic, habitats and vegetation layers, both at permanent sampling plots and through ad-hoc sampling en route. The dataset includes occurrences from 53 geographical points with 10,500 records and more than 35,000 specimens. This increases the existing data on Russian spiders on GBIF by four times, from 11,000 (excluding iNaturalist observations) to 46,000. The dataset allows for the exploration of regional fauna, local and general species distribution, spider phenology and habitat preferences for the purposes of monitoring and conservation.

Temperature Response of Whole-plant CO2 Exchange Rates of Magnolia (Magnolia grandiflora L.)

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 511d-511
Author(s):  
Marc W. van Iersel ◽  
Orville M. Lindstrom
Keyword(s):  
Dark Respiration ◽  
Temperature Response ◽  
Net Photosynthesis ◽  
Co2 Exchange ◽  
Limiting Factor ◽  
Response Curves ◽  
Gross Photosynthesis ◽  
Temperature Range ◽  
Whole Plant ◽  
Increasing Temperature

Photosynthesis and respiration temperature-response curves are useful in predicting the ability of plants to perform under different environmental conditions. Whole crop CO2 exchange of two groups of magnolia `Greenback' plants was measured over a 26 °C temperature range. Net photosynthesis (Pnet) increased from 2 to 17% C and decreased again at higher temperatures. The Q10 for Pnet decreased from ≈4 at 6 °C to 0.5 at 24 °C. The decrease in Pnet at temperatures over 17 °C was caused by a rapid increase in dark respiration (Rdark) with increasing temperature. The Q10 for Rdark was estimated by fitting an exponential curve to data, resulting in a temperature-independent Q10 of 2.8. Gross photosynthesis (Pgross), estimated as the sum of Rdark and Pnet, increased over the entire temperature range (up to 25 °C). The Q10 for Pgross decreased with increasing temperature, but remained higher than 1. The data suggest that high respiration rates may be the limiting factor for growth of magnolia exposed to high temperatures, since it may result in a net carbon loss from the plants. At temperatures below 5 °C, both Pnet and Rdark become low and the net CO2 exchange of the plants would be expected to be minimal.

scholarly journals Auxin Applications Affect Posttransplant CO2 Exchange Rate and Growth of Bare-rooted Vinca [Catharanthus roseus (L.) G. Don] Seedlings

1999 ◽  
Vol 124 (3) ◽  
pp. 234-238 ◽  
Author(s):  
Marc van Iersel
Keyword(s):  
Exchange Rate ◽  
Catharanthus Roseus ◽  
Dark Respiration ◽  
Net Photosynthesis ◽  
Dry Mass ◽  
Co2 Exchange ◽  
Naphthaleneacetic Acid ◽  
Negative Effects ◽  
Transplant Shock ◽  
Whole Plant

Uprooting and transplanting seedlings can cause root damage, which may reduce water and nutrient uptake. Initiation of new roots and rapid elongation of existing roots may help minimize the negative effects of transplant shock. In this study, seedlings with four true leaves were transplanted into diatomaceous earth and the plants were transferred to a growth chamber, where they were treated with NAA (0, 0.025, 0.25, and 2.5 mg·L-1; 36 mL/plant). The effects of drenches with various amounts of 1-naphthaleneacetic acid (NAA) on the posttransplant CO2 exchange rate of vinca [Catharanthus roseus (L.) G. Don] were quantified. Whole-plant CO2 exchange rate of the plants was measured once every 20 minutes for a 28 day period. Seedlings treated with 0.025 or 0.25 mg·L-1 recovered from transplant shock more quickly than plants in the 0 and 2.5 mg·L-1 treatments. Naphthaleneacetic acid drenches containing 0.025 or 0.25 mg·L-1 increased whole-plant net photosynthesis (Pnet) from 10 days, dark respiration (Rdark) from 12 days, and carbon use efficiency (CUE) from 11 days after transplanting until the end of the experiment. The increase in CUE seems to have been the result of the larger size of the plants in these two treatments, and thus an indirect effect of the NAA applications. These differences in CO2 metabolism among the treatments resulted in a 46% dry mass increase in the 0.025 mg·L-1 treatment compared to the control, but shoot-root ratio was not affected. The highest rate of NAA (2.5 mg·L-1) was slightly phytotoxic and reduced the growth rate of the plants.

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