Altitudinal Variation in the Photosynthetic Characteristics of Snow Gum, Eucalyptus pauciflora Sieb. Ex Spreng. III. Temperature Response of Material Grown in Contrasting Thermal Environments

1977 ◽  
Vol 4 (2) ◽  
pp. 301 ◽  
Author(s):  
RO Slatyer
Keyword(s):  
Growth Temperature ◽  
Strong Dependence ◽  
Temperature Response ◽  
Net Photosynthesis ◽  
High Elevation ◽  
Similar Response ◽  
Site Location ◽  
Temperature Optimum ◽  
Response Curves ◽  
Thermal Environments

Photosynthetic temperature response curves were measured on seedlings of E. pauciflora grown from seed collected at high (1770 m) and low (915 m) elevation sites, in the Snowy Mountains. The material was grown in contrasting day/night temperature regimes (33/28 and 15/10°C) in the Canberra phytotron. The material from the high elevation site showed a temperature optimum at about 20°C when grown at 15/10°C and at about 25°C when grown at 33/28°C. By comparison, the temperature optimum for the low elevation material was near 25° when grown at 15/10°C and shifted to about 30° when grown at 33/28°C. The general form of the temperature response curves was similar for both sets of material, although net photosynthesis of the higher elevation material dropped off more rapidly at temperatures above and below the optimum. When grown at 15/10�C, peak Ievels of net photosynthesis were higher in the high elevation material (66 ng cm-2 s-1 v. 54 ng cm-2 s-1). When grown at 33/28°C, peak levels were higher in the low elevation material (78 ng cm-2 s-1 v. 60 ng cm-2 s-1). Similar response patterns were observed in intracellular resistance, ri, and gas phase resistance, ri, although there was relatively more change in ri, and relatively less change in ri, with respect to growth temperature and material, than in net photosynthesis. The most conservative parameter that was measured was the CO2 compensation point, Γ. Although it showed a strong dependence on measurement temperature, Γ was not significantly influenced by growth temperature or site location at the levels of probability used.

Altitudinal Variation in the Photosynthetic Characteristics of Snow Gum, Eucalyptus pauciflora Sieb. ex Spreng. IV. Temperature Response of Four Populations Grown at Different Temperatures

1977 ◽  
Vol 4 (4) ◽  
pp. 583 ◽  
Author(s):  
RO Slayter
Keyword(s):  
Field Study ◽  
Growth Temperature ◽  
Temperature Response ◽  
Net Photosynthesis ◽  
Tree Line ◽  
Temperature Optimum ◽  
Response Curves ◽  
Preferred Temperature ◽  
Co2 Compensation Point ◽  
Preferred Temperatures

Photosynthetic temperature response curves were measured at leaf temperatures from 10 to 40°C on seedlings of E. pauciflora grown from seed collected at tree-line (elevation 1905 m) in the Snowy Mountains area and at three lower elevations, 915, 1215 and 1645 m, which correspond to those used in an earlier field study (Slatyer and Morrow 1977). The material was grown in naturally lit, temperature-controlled greenhouses at day/night temperatures of 8/4, 15/10, 21/16, 27/22 and 33/28°C. Comprehensive measurements were made on the tree-line population, in which peak rates of net photosynthesis, Pamb, reached 75 ng cm-2 s-1 at a temperature of 20�°C, from material grown at 21/16°. Minimum levels of intracellular resistance, rt, were 2.8 s cm-1, and of leaf gas-phase resistance to CO2 transfer, r1, were 3.2 s cm-1. Changes in rt and r1, with measurement temperature, appeared to be of approximately equal importance in mediating the overall photosynthetic temperature response. Changes in the CO2 compensation point, Γ were of increasing importance at higher measurement temperatures. The photosynthetic temperature optimum was markedly affected by the growth temperature regime. In the tree-line population, it increased from about 16° when grown at 8/4° to 24° when grown at 33/28°. The relationship between the observed photosynthetic temperature optimum and the day temperature of the growth regime indicated a preferred temperature for photosynthesis of 20.0°, and a tendency for the temperature optimum to shift by 0.34° per degree shift in the day growth temperature. A similar effect of growth temperature on the photosynthetic temperature optimum was noted in the three lower-elevation populations, in which preferred temperatures of 21.5, 24.2 and 27.2° were calculated for the material collected at 1645, 1215 and 915 m respectively. These temperatures were several degrees higher than the field-observed temperature optima, although the gradient of preferred temperature with elevation was comparable to that noted in the field study.

Altitudinal Variation in the Photosynthetic Characteristics of Snow Gum, Eucalyptus pauciflora Sieb. ex Spreng. VI. Comparison of Field and Phytotron Responses to Growth Temperature

1977 ◽  
Vol 4 (6) ◽  
pp. 901 ◽  
Author(s):  
RO Slayter
Keyword(s):  
Growth Temperature ◽  
Temperature Response ◽  
Net Photosynthesis ◽  
Equivalent Temperature ◽  
Temperature Optimum ◽  
Response Curves ◽  
Preferred Temperature ◽  
Practical Applications ◽  
Field Temperature ◽  
Temperature Optima

A procedure for estimating field photosynthetic temperature optima from phytotron temperature response data, for elevational populations of E. pauciflora, is developed. It utilizes the principle that each population has a preferred temperature, Tpref, and an acclimation coefficient, α, which can be determined from phytotron-derived temperature response curves, and which enable the photosynthetic temperature optimum observed in a particular field temperature regime (Test) to be estimated from the expression Test = Tpref - α(Tpref - Tequiv), where Tequiv is a field temperature equivalent, in terms of its effect on the photosynthetic temperature optimum, to a known phytotron growth temperature. Application of the procedure to sets of field and greenhouse data suggests that when Tpref and α are based on phytotron day growth temperatures, and when Tequiv is based on the proposition that a square-wave conversion of the field day-time temperature curve is equivalent to the phytotron day growth temperature, estimates of field and greenhouse temperature optima can be made which give good agreement with observed values. The agreement is best when active, current-year tissue is used as a basis of the field observations and when single leaves rather than shoots are used for field measurements. The procedure is also used to compare actual rates of net photosynthesis, Pamb, obtained from field and phytotron studies, when both are plotted against equivalent temperature. Using this procedure, the large apparent differences between rates of net photosynthesis observed in the field and in the phytotron can be considerably reduced. This suggests that the notion of equivalent temperature may provide a useful means of minimizing the effects of physical, temperature-related differences in comparing field and phytotron responses, thereby widening the range of practical applications of phytotron experiments.

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.

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.

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.

scholarly journals (112) Heat and Drought Affect Photosynthesis of Sugar Maple (Acer saccharum) Ecotypes

HortScience ◽  
2005 ◽  
Vol 40 (4) ◽  
pp. 1079A-1079
Author(s):  
Jason J. Griffin
Keyword(s):  
Water Potential ◽  
Great Plains ◽  
Acer Saccharum ◽  
Sugar Maple ◽  
Temperature Response ◽  
Net Photosynthesis ◽  
Field Studies ◽  
Response Curves ◽  
Original Weight ◽  
Prolonged Drought

Common sugar maple (Acer saccharum Marshall) selections suffer from prolonged drought and constant wind on the southern Great Plains. Nonirrigated plants often have scorched and torn leaves as a result of these environmental stresses. In field studies, a sugar maple ecotype native to western Oklahoma (known as `Caddo' maple) has shown improved tolerance to drought and leaf tatter. A study to examine drought tolerance of seedling `Caddo' maple compared to typical seedling sugar maple was established at the John C. Pair Horticultural Center. One seedling of each type was planted in a single 38-L container. Containers were placed on a greenhouse bench, and once acclimated, irrigation was withheld until predawn leaf water potential indicated a substrate water potential of –1.5 MPa. Containers were weighed, and seedlings were maintained in a prolonged drought condition for 3 weeks by adding water each morning to return the container to the original weight. After 3 weeks, photosynthetic temperature response curves were generated for the drought-stressed and the irrigated control plants. Osmotic potential of expressed sap was also measured on rehydrated leaves. The main effects of species, irrigation, and temperature were all significant. `Caddo' maples were able to maintain a higher rate of net photosynthesis than the typical seedlings when drought stressed and as temperature increased. The optimum temperature for photosynthesis did not significantly differ among treatments (36 °C), whereas the maximum rate of photosynthesis was significantly greater for the `Caddo' maples (41 μmol·m-2·s-1) than the typical sugar maples (16 μmol·m-2·s-1).

scholarly journals Within-crown Variation in the Development of Photosynthetic Capacity Is Proportional to Growth Temperature in Temperate Deciduous Trees

HortScience ◽  
2006 ◽  
Vol 41 (4) ◽  
pp. 999A-999
Author(s):  
William L. Bauerle ◽  
Joseph D. Bowden ◽  
Geoff G. Wang
Keyword(s):  
United States ◽  
Growth Temperature ◽  
Photosynthetic Capacity ◽  
Acer Rubrum ◽  
Temperature Acclimation ◽  
Red Maple ◽  
Temperature Optimum ◽  
Bisphosphate Carboxylase ◽  
Regeneration Rate ◽  
Thermal Environments

This study set out to test the hypothesis that the development in the capacity for the maximal rate of ribulose-1,5-bisphosphate carboxylase/oxygenase (VCmax) and the maximum regeneration rate of ribulose-1,5-bisphosphate (Jmax) per unit mass is proportional to the growth temperature under which the leaf develops and to investigate whether the capacity for photosynthetic acclimation to temperature varies genetically within a species by testing genotypes that originated from diverse thermal environments. Acer rubrum L. (red maple) genotypes were subjected to short-term and long-term temperature alteration to investigate the photosynthetic response. We minimized the variation of within-crown light gradients by growing trees in open grown field conditions and controlled temperature on a crown section basis. Thus, we singled out the temperature acclimation affects on the photosynthetic temperature optimum. In response to temperature acclimation, the genotype from the northern United States downregulated both VCmax and Jmax and had a 5 and 3 °C lower temperature optimum than the genotype native to the southern United States. The activation energy increased and was higher for Jmax than for VCmax in both genotypes. With respect to respiration, both genotypes downregulated about 0.5 μmol·m-2·s-1. Although respiration was lower, the increased energy of activation in response to growth temperature resulted in a decrease in maximum net photosynthetic rate (Amax) under saturating light and CO2. The results illustrate that the photosynthetic capacity adjusted in response to growth temperature but the temperature optimum was different among genotypes.

Pituitary response to LRH and TRH stimulation and peripheral steroid hormones in conscious and anaesthetized adult male rhesus monkeys (Macaca mulatta)

1980 ◽  
Vol 93 (3) ◽  
pp. 287-293 ◽  
Author(s):  
E. Jean Wickings ◽  
E. Nieschlag
Keyword(s):  
Adult Male ◽  
Rhesus Monkeys ◽  
Serum Testosterone ◽  
Fold Increase ◽  
Serum Cortisol ◽  
Serum Levels ◽  
Biologically Active ◽  
Similar Response ◽  
Response Curves ◽  
Male Rhesus

Abstract. Adult male rhesus monkeys are aggressive animals and very difficult to handle. Hence experimental manipulations necessarily involve the use of restraint procedures, either chemical or physical, which may influence endocrine functions. Therefore, the effects of ketamine anaesthesia on basal hormone levels and on the pituitary response to LRH and TRH were investigated in 4 adult male rhesus monkeys. Values were compared to those obtained from the same animals restrained in primate chairs for approximately 48 h, a procedure to which they had been accustomed to over the preceding 6 months. Serum cortisol levels under anaesthesia were at all times lower than in conscious monkeys, but increased after 2 h to values twice as high as measured initially. Serum testosterone concentrations were not significantly different on the two occasions, but levels under anaesthesia were slightly higher initially than in the conscious monkeys, and decreased gradually over the 3 h test period. Initial prolactin levels were lower in the anaesthetized monkeys, and increased 2–3-fold after 90 min; values at 3 h were not significantly different from those in conscious monkeys. Intravenous TRH elicited a similar response in prolactin on both occasions, maximum values occurring after 15–30 min and returning to basal levels after 3 h. The maximum values attained and the area under the response curves were higher under anaesthesia. LRH stimulation resulted in a 15- and 30-fold increase in serum levels of biologically active LH, with and without anaesthesia, respectively. Basal levels were not significantly different on the two occasions. The area under the LH response curve was higher in 3 of the 4 monkeys without anaesthesia. The extent to which results in conscious monkeys are affected by stress is difficult to assess. Since neither handling technique allows for the collection of 'true' basal data, it is paramount to standardize and define the conditions under which experiments, and even routine blood sampling, are performed in male rhesus monkeys.

scholarly journals Differences in Leaf Temperature between Lianas and Trees in the Neotropical Canopy

2018 ◽  
Author(s):  
J. Antonio Guzmán Q. ◽  
G. Arturo Sánchez-Azofeifa ◽  
Benoit Rivard
Keyword(s):  
Primary Productivity ◽  
Net Primary Productivity ◽  
Temperature Response ◽  
Life Forms ◽  
Leaf Temperature ◽  
Response Curves ◽  
Tropical Environments ◽  
Host Trees ◽  
Temperature Responses ◽  
Photosynthesis And Respiration

Leaf temperature (Tleaf) influences photosynthesis and respiration. Currently, there is a growing interest on including lianas in productivity models due to their increasing abundance, and their detrimental effects on net primary productivity in tropical environments. Therefore, understanding the differences of Tleaf between lianas and trees is important for future of forest on whole ecosystem productivity. Here we determined the displayed leaf temperature (Td= Tleaf – ambient temperature) of several species of lianas and their host trees during ENSO and non-ENSO years to evaluate if the presence of lianas affects the Td of their host trees, and if leaves of lianas and their host trees exhibit differences in Td. Our results suggest that close to midday, the presence of lianas does not affect the Td of their host trees; however, lianas tend to have higher values of Td than their hosts across seasons, in both ENSO and non-ENSO years. Although lianas and trees tend to have similar physiological-temperature responses, differences in Td could lead to significant differences in rates of photosynthesis and respiration based temperature response curves. Future models should thus consider differences in leaf temperature between these life forms to achieve robust predictions of productivity.

Acclimation of leaf dark respiration to nocturnal and diurnal warming in a semiarid temperate steppe

2013 ◽  
Vol 40 (11) ◽  
pp. 1159 ◽  
Author(s):  
Yonggang Chi ◽  
Ming Xu ◽  
Ruichang Shen ◽  
Shiqiang Wan
Keyword(s):  
Dark Respiration ◽  
Temperature Response ◽  
Terrestrial Ecosystems ◽  
Northern China ◽  
Thermal Acclimation ◽  
Nonstructural Carbohydrates ◽  
Temperate Steppe ◽  
Response Curves ◽  
Diurnal Warming ◽  
Leaf Dark Respiration

A better understanding of thermal acclimation of leaf dark respiration in response to nocturnal and diurnal warming could help accurately predict the changes in carbon exchange of terrestrial ecosystems under global warming, especially under the asymmetric warming. A field manipulative experiment was established with control, nocturnal warming (1800–0600 hours), diurnal warming (0600–1800 hours), and diel warming (24 h) under naturally fluctuating conditions in a semiarid temperate steppe in northern China in April 2006. Temperature response curves of in situ leaf dark respiration for Stipa krylovii Roshev. were measured at night (Rn) and after 30 min of darkness imposed in the daytime (Rd). Leaf nonstructural carbohydrates were determined before sunrise and at sunset. Results showed that Rn could acclimate to nocturnal warming and diurnal warming, but Rd could not. The decreases in Q10 (temperature sensitivity) of Rn under nocturnal-warming and diurnal warming regimes might be attributed to greater depletion of total nonstructural carbohydrates (TNC). The real-time and intertwined metabolic interactions between chloroplastic and mitochondrial metabolism in the daytime could affect the impacts of warming on metabolite pools and the distinct response of Rn and Rd to warming. Projection on climate change–carbon feedback under climate warming must account for thermal acclimation of leaf dark respiration separately by Rn and Rd.

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