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.

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.

scholarly journals Morphological bases of phytoplankton energy management and physiological responses unveiled by 3D subcellular imaging

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Clarisse Uwizeye ◽  
Johan Decelle ◽  
Pierre-Henri Jouneau ◽  
Serena Flori ◽  
Benoit Gallet ◽  
...  
Keyword(s):  
Energy Management ◽  
Morphometric Analysis ◽  
Physiological Responses ◽  
High Light ◽  
Phytoplankton Diversity ◽  
Eukaryotic Phytoplankton ◽  
Evolutionarily Conserved ◽  
Photosynthetic Responses ◽  
Photosynthesis And Respiration ◽  
Subcellular Imaging

AbstractEukaryotic phytoplankton have a small global biomass but play major roles in primary production and climate. Despite improved understanding of phytoplankton diversity and evolution, we largely ignore the cellular bases of their environmental plasticity. By comparative 3D morphometric analysis across seven distant phytoplankton taxa, we observe constant volume occupancy by the main organelles and preserved volumetric ratios between plastids and mitochondria. We hypothesise that phytoplankton subcellular topology is modulated by energy-management constraints. Consistent with this, shifting the diatom Phaeodactylum from low to high light enhances photosynthesis and respiration, increases cell-volume occupancy by mitochondria and the plastid CO2-fixing pyrenoid, and boosts plastid-mitochondria contacts. Changes in organelle architectures and interactions also accompany Nannochloropsis acclimation to different trophic lifestyles, along with respiratory and photosynthetic responses. By revealing evolutionarily-conserved topologies of energy-managing organelles, and their role in phytoplankton acclimation, this work deciphers phytoplankton responses at subcellular scales.

scholarly journals Seasonal Differences in Growth, Photosynthetic Pigments and Gas Exchange Properties in Two Greenhouse Grown Maize (Zea Mays L.) Cultivars

2014 ◽  
Vol 73 (2) ◽  
pp. 333-345 ◽  
Author(s):  
Iqbal Hussain ◽  
Abdul Wahid ◽  
Rizwan Rasheed ◽  
Hafiz Muhammad Akram
Keyword(s):  
Zea Mays L ◽  
Crop Yields ◽  
Canopy Temperature ◽  
Net Photosynthesis ◽  
Grain Filling ◽  
Dry Mass ◽  
Growth Stages ◽  
Cropping Patterns ◽  
Photosynthetic Responses ◽  
Photosynthetic Attributes

Abstract The greenhouse (GH) effect has emerged as a major factor in changing cropping patterns and limiting crop yields. This study was conducted to determine the comparative growth and photosynthetic responses of selected heat-resistant (cv. Sadaf) and heat-susceptible (cv. Agatti-2002) cultivars of maize to simulated GH conditions during spring and autumn seasons at seedling, silking and grain filling stages in 2007. Fifteen day old plants were shifted to plexiglass-fitted canopies to create GH conditions and data were recorded at each growth stage. The results revealed that the seasons, GH conditions and cultivars had large effects on plant growth and photosynthetic attributes. Simulated GH conditions increased the canopy temperature 4-7 °C in spring and 3-5 °C in autumn, but increased relative humidity by 2-3% in spring and 5-9% in autumn season. Although GH reduced the growth of both cultivars, shoot dry mass was reduced more in spring grown heat-susceptible maize at all growth stages. Although the cultivars showed a decrease in growth and photosynthesis, GH conditions resulted in less damage to cv. Sadaf than cv. Agatti-2002 in both seasons. Major indicators of sensitivity to GH effect were loss of chlorophyll b and carotenoids, reductions in net photosynthesis and stomatal conductance, and possibly reduced ability of Rubisco to fix CO2 in sensitive maize.

Physiological responses of semiarid grasses. IV.* Photosynthetic rates of Thyridolepis mitchelliana and Cenchrus ciliaris leaves

1975 ◽  
Vol 26 (3) ◽  
pp. 459 ◽  
Author(s):  
EK Christie
Keyword(s):  
Leaf Surface ◽  
Physiological Responses ◽  
Carbon Dioxide Concentration ◽  
Assimilation Rate ◽  
Chloroplast Structure ◽  
Response Curves ◽  
The Poor ◽  
C4 Species ◽  
Net Assimilation ◽  
Photosynthetic Responses

Photosynthesis response curves of mulga and buffel grasses to irradiance and to carbon dioxide concentration, together with studies of leaf anatomy and chloroplast structure, showed that the former was a C3 and the latter a C4 species. This is held to account for the large differences in growth rate between the two species. Although Mitchell grass has the anatomy of a C4 species, its photosynthetic responses were not examined. As its net assimilation rate is high at high temperatures, its generally low growth rates are associated with the poor development of its leaf surface. *Part III, Aust. J. Aguic. Res., 26: 447 (1975).

What drives photosynthesis during desiccation? Mosses and other outliers from the photosynthesis–elasticity trade-off

2020 ◽  
Vol 71 (20) ◽  
pp. 6460-6470
Author(s):  
Alicia V Perera-Castro ◽  
Miquel Nadal ◽  
Jaume Flexas
Keyword(s):  
Vascular Plants ◽  
Photosynthetic Capacity ◽  
Net Photosynthesis ◽  
Structural Features ◽  
Current View ◽  
Trade Off ◽  
Linear Dependency ◽  
Co2 Diffusion ◽  
Low Co2 ◽  
Photosynthetic Responses

Abstract In vascular plants, more rigid leaves have been linked to lower photosynthetic capacity, associated with low CO2 diffusion across the mesophyll, indirectly resulting in a trade-off between photosynthetic capacity (An) and bulk modulus of elasticity (ε). However, we evaluated mosses, liverworts, and Chara sp., plus some lycophytes and ferns, and found that they behaved as clear outliers of the An–ε relationship. Despite this finding, when vascular and non-vascular plants were plotted together, ε still linearly determined the cessation of net photosynthesis during desiccation both in species with stomata (either actively or hydro-passively regulated) and in species lacking stomata, and regardless of their leaf structure. The latter result challenges our current view of photosynthetic responses to desiccation and/or water stress. Structural features and hydric strategy are discussed as possible explanations for the deviation of these species from the An–ε trade-off, as well as for the general linear dependency between ε and the full cessation of An during desiccation.

scholarly journals Visible Foliar Injury and Physiological Responses to Ozone in Italian Provenances ofFraxinus excelsiorandF. ornus

2007 ◽  
Vol 7 ◽  
pp. 90-97 ◽  
Author(s):  
Nicla Contran ◽  
Elena Paoletti
Keyword(s):  
Gas Exchange ◽  
Physiological Responses ◽  
Carbon Assimilation ◽  
Woody Species ◽  
Green Ash ◽  
Foliar Injury ◽  
Visible Injury ◽  
Geographical Variations ◽  
Ecological Features ◽  
Visible Foliar Injury

We compared leaf visible injury and physiological responses (gas exchange and chlorophyll a fluorescence) to high O3exposure (150 nmol mol–1h, 8 h day–1, 35–40 days) of two woody species of the same genus with different ecological features: the mesophilic green ash (Fraxinus excelsior) and the xerotolerant manna ash (F. ornus). We also studied how provenances from northern (Piedmont) and central (Tuscany) Italy, within the two species, responded to O3exposure. Onset and extent of visible foliar injury suggested thatF. excelsiorwas more O3sensitive thanF. ornus. The higher stomatal conductance inF. ornusthan inF. excelsiorsuggested a larger potential O3uptake, in disagreement to lower visible foliar injury. The higher carbon assimilation inF. ornussuggested a higher potential of O3detoxification and/or repair. Contrasting geographical variations of ash sensitivity to O3were recorded, as Piedmont provenances reduced gas exchange less than Tuscan provenances inF. excelsiorand more inF. ornus. Visible injury was earlier and more severe inF. excelsiorfrom Piedmont than from Tuscany, while the provenance did not affect visible injury onset and extent inF. ornus.

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