scholarly journals Variation in species light acquisition traits under fluctuating light regimes: implications for non‐equilibrium coexistence

Oikos ◽  
2018 ◽  
Vol 128 (5) ◽  
pp. 716-728 ◽  
Author(s):  
Alexis Guislain ◽  
Beatrix E. Beisner ◽  
Jan Köhler
Keyword(s):  
Light Regimes ◽  
Equilibrium Coexistence ◽  
Fluctuating Light ◽  
Light Acquisition ◽  
Non Equilibrium

scholarly journals Growth under Fluctuating Light Reveals Large Trait Variation in a Panel of Arabidopsis Accessions

Plants ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 316 ◽  
Author(s):  
Elias Kaiser ◽  
Dirk Walther ◽  
Ute Armbruster
Keyword(s):  
Photosystem Ii ◽  
Chemical Potential ◽  
Genomic Variation ◽  
Operating Efficiency ◽  
Photochemical Quenching ◽  
Low Light ◽  
Trait Variation ◽  
Light Regimes ◽  
Fluctuating Light ◽  
Non Photochemical Quenching

The capacity of photoautotrophs to fix carbon depends on the efficiency of the conversion of light energy into chemical potential by photosynthesis. In nature, light input into photosynthesis can change very rapidly and dramatically. To analyze how genetic variation in Arabidopsis thaliana affects photosynthesis and growth under dynamic light conditions, 36 randomly chosen natural accessions were grown under uniform and fluctuating light intensities. After 14 days of growth under uniform or fluctuating light regimes, maximum photosystem II quantum efficiency (Fv/Fm) was determined, photosystem II operating efficiency (ΦPSII) and non-photochemical quenching (NPQ) were measured in low light, and projected leaf area (PLA) as well as the number of visible leaves were estimated. Our data show that ΦPSII and PLA were decreased and NPQ was increased, while Fv/Fm and number of visible leaves were unaffected, in most accessions grown under fluctuating compared to uniform light. There were large changes between accessions for most of these parameters, which, however, were not correlated with genomic variation. Fast growing accessions under uniform light showed the largest growth reductions under fluctuating light, which correlated strongly with a reduction in ΦPSII, suggesting that, under fluctuating light, photosynthesis controls growth and not vice versa.

scholarly journals Morphological, Anatomical, and Physiological Changes of Orchardgrass Leaves Grown under Fluctuating Light Regimes

2007 ◽  
Vol 99 (6) ◽  
pp. 1502-1513 ◽  
Author(s):  
Pablo L. Peri ◽  
Derrick J. Moot ◽  
Peter Jarvis ◽  
David L. McNeil ◽  
Richard J. Lucas
Keyword(s):  
Physiological Changes ◽  
Light Regimes ◽  
Fluctuating Light

scholarly journals Predator-mediated, non-equilibrium coexistence of tree-hole mosquitoes in southeastern North America

Oecologia ◽  
1983 ◽  
Vol 57 (1-2) ◽  
pp. 239-256 ◽  
Author(s):  
William E. Bradshaw ◽  
Christina M. Holzapfel
Keyword(s):  
North America ◽  
Equilibrium Coexistence ◽  
Tree Hole ◽  
Non Equilibrium

Light intensity and photosynthetic rates in phytoplankton

1973 ◽  
Vol 30 (12) ◽  
pp. 1771-1778 ◽  
Author(s):  
Graham P. Harris ◽  
John N. A. Lott
Keyword(s):  
Prolonged Exposure ◽  
High Light ◽  
Phytoplankton Species ◽  
Constant Illumination ◽  
Light Regimes ◽  
Steady Decrease ◽  
Fluctuating Light ◽  
Light Intensities ◽  
Controlling Mechanism ◽  
Reduced Surface

The physiological behavior of various phytoplankton species has been examined under increasing and decreasing light regimes. A marked asymmetry has been found, with photosynthesis rates under rising light intensities exceeding those under dimming lights. Photoinhibition has been observed at moderate light intensities (0.4–1.0 ly/min). Variations in the asymmetry and in photoinhibition appear to be correlated with the light regimes experienced by the population. Under constant illumination by full sunlight a steady decrease in the photosynthesis rate was observed. As a result of photosynthesis measurements in fluctuating light regimes there is now evidence for photorespiration as the controlling mechanism. Data are presented which show that prolonged exposure to high light has an adverse effect on photosynthesis and indicate that 14C moored bottle experiments may show reduced surface rates because of this.

Application of analytical electron microscopy to studies of equilibrium and non-equilibrium segregation in materials

1992 ◽  
Vol 50 (2) ◽  
pp. 1214-1215
Author(s):  
Edward A Kenik
Keyword(s):  
Electron Microscopy ◽  
Analytical Electron Microscopy ◽  
Extended Defects ◽  
Probe Diameter ◽  
Specimen Holder ◽  
Analytical Electron ◽  
Scanning Transmission ◽  
Solute Atoms ◽  
Equilibrium Segregation ◽  
Non Equilibrium

Segregation of solute atoms to grain boundaries, dislocations, and other extended defects can occur under thermal equilibrium or non-equilibrium conditions, such as quenching, irradiation, or precipitation. Generally, equilibrium segregation is narrow (near monolayer coverage at planar defects), whereas non-equilibrium segregation exhibits profiles of larger spatial extent, associated with diffusion of point defects or solute atoms. Analytical electron microscopy provides tools both to measure the segregation and to characterize the defect at which the segregation occurs. This is especially true of instruments that can achieve fine (<2 nm width), high current probes and as such, provide high spatial resolution analysis and characterization capability. Analysis was performed in a Philips EM400T/FEG operated in the scanning transmission mode with a probe diameter of <2 nm (FWTM). The instrument is equipped with EDAX 9100/70 energy dispersive X-ray spectrometry (EDXS) and Gatan 666 parallel detection electron energy loss spectrometry (PEELS) systems. A double-tilt, liquid-nitrogen-cooled specimen holder was employed for microanalysis in order to minimize contamination under the focussed spot.

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