A field study on the respiration rates in the leaves of temperate plants

1989 ◽  
Vol 67 (12) ◽  
pp. 3478-3481 ◽  
Author(s):  
Donald E. Collier ◽  
W. Raymond Cummins
Keyword(s):  
Field Study ◽  
Key Words ◽  
Dark Respiration ◽  
Alternative Pathway ◽  
Salicylhydroxamic Acid ◽  
Respiration Rates ◽  
Understory Herbs ◽  
Fluctuating Environments ◽  
Cyanide Resistance ◽  
Physiological Flexibility

The field respiration rates of leaves, in terms of total dark respiration, cytochrome (cyanide sensitive) pathway respiration, and alternative (salicylhydroxamic acid sensitive) pathway respiration, were measured in 10 temperate species. Five spring understory herbs and five ruderal species were used. All species displayed resistance to cyanide and sensitivity to salicylhydroxamic acid, indicating a capacity and some engagement of the alternative pathway. In comparison with reports on the field respiration rates of leaves in arctic and boreal species, the temperate plants had significantly less O2 uptake along both respiratory pathways. Rates of alternative pathway respiration in this study were comparable with those reported in the leaves of crop plants. In a comparison of respiration rates between the ruderal and understory species, the ruderal species had significantly greater activity along the alternative pathway. The ruderals also had a significantly greater capacity for the alternative pathway. It is proposed that the presence of the alternative pathway somehow allows physiological flexibility in the ruderals, and this in turn aids in their survival in fluctuating environments. Key words: alternative pathway, cyanide resistance, respiration, ruderal, understory.

Cyanide-resistant, alternative pathway respiration in guard cell protoplasts of Vicia faba

1994 ◽  
Vol 72 (2) ◽  
pp. 150-156 ◽  
Author(s):  
B. T. Mawson
Keyword(s):  
Vicia Faba ◽  
Blue Light ◽  
Guard Cell ◽  
Alternative Pathway ◽  
Electron Flow ◽  
Mesophyll Cell ◽  
Salicylhydroxamic Acid ◽  
Respiration Rates ◽  
Cytochrome Pathway ◽  
Guard Cell Protoplasts

The activity and capacity of cyanide-resistant or alternative pathway respiration was examined in Vicia faba L. guard and mesophyll cell protoplasts maintained either in darkness (dark adapted) or illuminated with blue light. Respiration rates by dark-adapted guard cell protoplasts were unaffected by titrating with salicylhydroxamic acid (0.1–2.0 mM), an inhibitor of alternative pathway respiration, suggesting the lack of activity of this pathway. In combination with 0.1 mM KCN, an inhibitor of cytochrome pathway respiration, salicylhydroxamic acid was effective in inhibiting total respiration rates. In contrast with guard cell protoplasts, salicylhydroxamic acid reduced rates of O2 consumption in dark-adapted mesophyll cell protoplasts by 25–30% of total respiration. Titrating the cytochrome pathway of guard cell protoplasts with KCN (10–140 μM) alone failed to reduce respiratory activity but was effective in combination with salicylhydroxamic acid. Addition of a proton ionophore, carbonyl cyanide m-chlorophenylhydraxone, to dark-adapted guard cell protoplast suspensions increased respiration by approximately 30 and 84% in the presence and absence of salicylhydroxamic acid, suggesting restriction of electron flow by adenylates. Illumination of guard cell protoplasts with blue light for 30 min increased the sensitivity of respiration to salicylhydroxamic acid and increased the activity of the alternative pathway over this time period to ~55% of total respiration. Blue light also increased the rate of uncoupled respiration by guard cell protoplasts treated with salicylhydroxamic acid compared with dark-adapted protoplasts. The results suggest that electron movement through either cytochrome or alternative pathways in guard cell mitochondria may be regulated during signal transduction of blue light. Key words: Vicia faba, guard cell protoplasts, alternative pathway, respiration, blue light.

Ritualinis mandagumas (ta’ârof) šiuolaikinio Irano visuomenėje ir tarpkultūrinėje komunikacijoje: Teherano šiaurinės dalies atvejis

2019 ◽  
Vol 19 (28) 2019 ◽  
pp. 169-190
Author(s):  
Dalia Sabaliauskienė
Keyword(s):  
Field Study ◽  
Key Words ◽  
Intercultural Communication ◽  
Capital City ◽  
Cultural Environment ◽  
City Culture ◽  
Face Maintenance

This paper examines the concept and practices of the Iranian ritual courtesy ta’ârof in northern Tehran, based on field-study findings, and analyses its expression in intercultural communication. It examines how contemporary Iranians perceive ta’ârof, what practices of ritual courtesy are commonly found, and whether configurations of the Iranian code of courtesy remain stable in the changing cultural environment. The study employs the theory of face maintenance and data from Iranian face and diaspora research. It shows emic perceptions of ta’ârof, and reveals its practices in Tehran, alongside tendencies of expression among Iranians living in Lithuania. Key words: ta’ârof, ritual courtesy, capital-city culture, intercultural communication, contemporary Iran.

Effect of forest harvesting and slash piling on microbial biomass and respiration in Newfoundland boreal forests

2007 ◽  
Vol 87 (4) ◽  
pp. 455-458 ◽  
Author(s):  
Martin T Moroni ◽  
Paul Q Carter ◽  
Dean W Strickland ◽  
Franz Makeschin ◽  
Don-Roger Parkinson ◽  
...  
Keyword(s):  
Microbial Biomass ◽  
Key Words ◽  
Boreal Forests ◽  
Fungal Biomass ◽  
Forest Harvesting ◽  
Organic Layer ◽  
Total Microbial Biomass ◽  
Organic Layers ◽  
Respiration Rates ◽  
Fumigation Extraction

Clearcutting Newfoundland boreal forests significantly reduced organic layer fungal and total microbial biomass in clearcut areas with and without slash cover, compared with forested plots. However, aerobically incubated respiration rates were highest in organic layers from clearcut areas under slash, intermediate under forests, and lowest from clearcut areas without slash. Key words: Carbon, ergosterol, fumigation–extraction, fungal biomass, harvest slash, nitrogen

A field study of competition and interaction between Lemna minor and Lemna trisulca

1989 ◽  
Vol 67 (10) ◽  
pp. 2904-2911 ◽  
Author(s):  
Alexander L. McIlraith ◽  
Gordon G. C. Robinson ◽  
Jennifer M. Shay
Keyword(s):  
Life History ◽  
Field Study ◽  
Key Words ◽  
Field Experiments ◽  
Lemna Minor ◽  
Survey Methods ◽  
The Other ◽  
Transplant Experiment ◽  
Replacement Series ◽  
Vegetative Biomass

Field experiments and survey methods were used to assess competition and interaction between Lemna minor L. and Lemna trisulca L. at Delta Marsh, Manitoba. Sites were dominated by one or the other species or codominated by both. Replacement series experiments predicted codominance of L. minor and L. trisulca in an unshaded eutrophic site but predicted L. minor dominance when run for a longer time. Similar experiments conducted in a shaded eutrophic site predicted L. minor dominance. Addition series experiments showed that intraspecific and interspecific competition occurred in the unshaded site. In a eutrophic unshaded ditch, high densities of L. minor suppressed L. trisulca. In a eutrophic shaded site, high densities of L. minor and green algae inhibited L. trisulca, and in a sunny, less eutrophic site high density of each species inhibited the other. In a transplant experiment, L. minor biomass in shaded enclosures approached that found naturally in two shaded sites. Lemna trisulca persisted when shaded. Vegetative biomass trends in an unshaded eutrophic marsh ditch indicated spring and fall L. trisulca dominance and summer L. minor dominance. Shaded eutrophic sites were dominated by L. minor, whereas a less eutrophic site was dominated by L. trisulca. A model is developed to explain dominance patterns, and seasonal life-history responses are considered. Key words: Lemna, duckweed, competition, interaction, resources, light, nutrients.

Pertes de charge des ancrages actifs injectés dans un massif rocheux

1989 ◽  
Vol 16 (1) ◽  
pp. 72-81 ◽  
Author(s):  
Brahim Benmokrane ◽  
Gérard Ballivy
Keyword(s):  
Epoxy Resin ◽  
Field Study ◽  
Key Words ◽  
Solid Rock ◽  
Rapid Loss ◽  
Prestress Loss ◽  
Massif Rocheux ◽  
Second Stage ◽  
Initial Stage

Estimation of loss of prestress is an essential part of the design of permanent or temporary prstressed anchors since stability of the retained structure must not be compromised. Findings of a field study on long-term behaviour of prestressed anchors are presented herein: different lengths of anchors in solid rock were injected with cement grout or epoxy resin. Load variation in the anchors with time indicated two distinct stages of loss of prestress: an initial stage of rapid loss of prestress and a second stage of very minor and uniform loss ending about 6 months after prestressing. Our study also showed that restressing anchors after a period of time reduces subsequent prestress loss and that overdimensioning of the injected length does not. Key words: rock, prestressed injected anchor, grout, loss of prestress, creep, relaxation.

No difference in leaf respiration rates among temperate, subarctic, and arctic species grown under controlled conditions

1996 ◽  
Vol 74 (2) ◽  
pp. 317-320 ◽  
Author(s):  
Donald E. Collier
Keyword(s):  
Growth Temperature ◽  
Alternative Pathway ◽  
Geographic Origin ◽  
Temperature Acclimation ◽  
Temperate Species ◽  
Leaf Respiration ◽  
Arctic Species ◽  
Respiration Rates ◽  
Controlled Conditions ◽  
Plant Groups

To test the theory that leaf respiration rates are inherently higher in arctic species compared with temperate species, a total of 35 species from temperate, subarctic, and arctic locations were grown under controlled conditions and leaf respiration rates were measured. Regardless of growth temperature (either 10 or 20 °C), leaf respiration rates measured at the growth temperature were independent of a species' geographic origin. In addition, salicylhydroxamic acid inhibited the alternative oxidase equally in all groups of species. Acclimation of leaf respiration to temperature was observed in all three geographic plant groups, i.e., leaf respiration rates of 20 °C-grown plants were not significantly different than rates of 10 °C-grown plants when respiration was measured at the growth temperature. These results suggest that arctic species do not have inherently high leaf respiration rates, higher alternative pathway respiration, or greater temperature acclimation ability compared with temperate species. Keywords: alternative pathway respiration, arctic, leaf respiration, subarctic, temperate, temperature.

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.

Observations of the Photosynthetic Physiology of Tree Species within the C3 Monocotyledon Genus Pandanus, and Comparison with Dicotyledon C3 Tree Species

1998 ◽  
Vol 46 (1) ◽  
pp. 103 ◽  
Author(s):  
Catherine E. Lovelock
Keyword(s):  
Leaf Area ◽  
Specific Leaf Area ◽  
Tree Species ◽  
Dark Respiration ◽  
Dry Weight ◽  
Weight Basis ◽  
Growth And Survival ◽  
Respiration Rates ◽  
Leaf Dark Respiration ◽  
Resource Levels

Photosynthetic characteristics of tree species from the tropical C3 monocotyledon genus Pandanus were compared with C3 dicotyledon species growing in similar environments. The Pandanus species had similar maximum photosynthetic rates (Amax) to dicotyledon tree species in leaves from both sun and shaded environments when Amax was expressed on an area basis. Because of the low specific leaf area of the schlerophyllous leaves of the Pandanus compared to the dicotyledon species, the similarity in Amax was no longer evident when Amax was expressed on a dry-weight basis. Leaf dark respiration rates of the Pandanus on a leaf area and weight basis were generally lower than the shade-intolerant dicotyledons and similar to the shade-tolerant dicotyledon species. Low dark respiration rates and low specific leaf area of the Pandanus may be important characteristics for growth and survival in environments where resource levels are low and the likelihood of tissue damage is high.

PARAQUAT-INDUCED CHANGES IN SELECTED RHIZOBIA AND AGROBACTERIA

1985 ◽  
Vol 65 (4) ◽  
pp. 667-675 ◽  
Author(s):  
E. B. ROSLYCKY
Keyword(s):  
Agrobacterium Tumefaciens ◽  
Key Words ◽  
Rhizobium Meliloti ◽  
Cell Permeability ◽  
Group Affiliation ◽  
Rhizobium Phaseoli ◽  
Respiration Rates ◽  
Induced Changes

Adaptations of eight strains of rhizobia from seven cross-inoculation groups and of two agrobacteria from two species to paraquat, in concentrations up to 20 000 μg∙mL−1, affected 11 of the 40 properties studied, including carbohydrate, nitrogen, sulfur, and other metabolism. The number of characteristics altered varied among the bacteria without species or group affiliation. Of the total of 18 changes, 13 occurred in Rhizobium meliloti 22 and R. trifolii 7 and 42, while R. leguminosarum 56, R. lupini 112, R. japonicum 80, cowpea strain 131, and Agrobacterium tumefaciens A6-K1 had only one. Rhizobium phaseoli 95 and A. radiobacter R-590 remained unaffected. Generally, the adapted organisms produced lower nephelometric growth and manometric respiration rates at 0 and 200 μg of paraquat∙mL−1, relative to the herbicide-free parent controls. Tolerance of R. trifolii 7 to NaCl increased from 1% to 5% (wt/vol). The findings suggest that paraquat may have affected cell permeability, adaptive and/or constitutive enzymes in these bacteria. Key words: Rhizobia, agrobacteria, adaptations, physiology, paraquat and herbicides

THE EFFECT OF LACTATION ON OUABAIN-SENSITIVE RESPIRATION OF THE DUODENAL MUCOSA OF COWS

1984 ◽  
Vol 64 (4) ◽  
pp. 817-824 ◽  
Author(s):  
B. W. McBRIDE ◽  
L. P. MILLIGAN
Keyword(s):  
Energy Expenditure ◽  
Atpase Activity ◽  
Key Words ◽  
Duodenal Mucosa ◽  
Maintenance Energy ◽  
Respiration Rates ◽  
Lactating Cows ◽  
Peak Lactation

Total O2 consumption, ouabain-sensitive and ouabain-insensitive respiration rates were measured for the duodenal mucosa of non-lactating and lactating cows. Support of Na+, K+-ATPase activity, as measured by ouabain-sensitive respiration, accounted for 55% of total mucosal respiration of the cows at peak lactation. In mid-lactation and during the non-lactating period the proportion of O2 uptake inhibited by ouabain declined to 34–35%; the amount of ouabain-sensitive O2 uptake declined from 3.6–4.0 to 2.5–2.8 μL O2/mg tissue per hour. The magnitude of ouabain-insensitive respiration was highest during late lactation and the non-lactating period. It was concluded that Na+, K+-ATPase accounted for a major proportion of the duodenal mucosa maintenance energy expenditure. The magnitude of this expenditure is not constant throughout lactation. Key words: Na+, K+-ATPase, duodenal mucosa, O2 consumption, cows

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