Photoinhibition of photosynthesis in intact kiwifruit (Actinidia deliciosa) leaves: Effect of temperature

Planta ◽  
1988 ◽  
Vol 174 (2) ◽  
pp. 152-158 ◽  
Author(s):  
D. H. Greer ◽  
W. A. Laing ◽  
T. Kipnis
Keyword(s):  
Actinidia Deliciosa ◽  
Effect Of Temperature ◽  
Photoinhibition Of Photosynthesis

Effect of Temperature on Photoinhibition and Recovery in Actinidia deliciosa

1988 ◽  
Vol 15 (2) ◽  
pp. 195 ◽  
Author(s):  
DH Greer
Keyword(s):  
Light Exposure ◽  
Photochemical Reactions ◽  
High Light ◽  
Actinidia Deliciosa ◽  
Radiative Energy ◽  
Effect Of Temperature ◽  
Photoinhibition Of Photosynthesis ◽  
Temperature Dependent ◽  
Protection Mechanism ◽  
Kinetics Of

Photoinhibition of photosynthesis was induced in intact leaves of kiwifruit (Actinidia deliciosa) grown in natural light not exceeding a photon irradiance (PI) of 300 �mol m-2 s-1 by exposing them to a PI of 1500 �mol m-2 s-1. The temperature was held constant during the high-light exposure between 5 and 35°C. Recovery was followed at temperatures between 10 and 35°C, after photoinhibition was induced by a 240 min exposure to high light. The kinetics of photoinhibition and recovery were followed by chlorophyll fluorescence at 692 nm and 77K. Photoinhibition occurred at all temperatures but was greatest at low temperatures. Temperature affected the severity of photoinhibitory damage but not the kinetics of photoinhibition. Recovery was also temperature-dependent with little or no recovery occurring below about 20°C and rapid recovery at 30-35°C. The extent of photoinhibition also affected the rates of recovery which were reduced as the severity of photoinhibition increased. An analysis of the rate constants for energy transfer within photosystem II indicated that kiwifruit leaves have some capacity to prevent photoinhibition by increasing the amount of non-radiative energy dissipation. However, the analysis also indicates that this protection mechanism was not wholly effective since the primary photochemical reactions apparently become inactivated during exposure of these leaves to high light.

The Effect of Chloramphenicol on Photoinhibition of Photosynthesis and Its Recovery in Intact Kiwifruit (Actinidia deliciosa) Leaves

1993 ◽  
Vol 20 (1) ◽  
pp. 33 ◽  
Author(s):  
DH Greer ◽  
WA Laing ◽  
DJ Woolley
Keyword(s):  
Chlorophyll Fluorescence ◽  
Co2 Exchange ◽  
High Light ◽  
Actinidia Deliciosa ◽  
Thermal Dissipation ◽  
Radiative Energy ◽  
Minor Effect ◽  
Photoinhibition Of Photosynthesis ◽  
Fluorescence Measurements ◽  
Time Courses

Photoinhibition of photosynthesis in kiwifruit [Actinidia deliciosa (A. Chev.) C. F. Liang et A. R. Ferguson] leaves in high light and its subsequent recovery in low light was assessed in the presence of chloramphenicol (CAP), an inhibitor of chloroplast-encoded protein synthesis. Rooted cuttings were grown in a controlled environment at a photosynthetic irradiance of 700 μmol m-2 s-1 and a day/night temperature of 25/20�C. Time-courses of photoinhibition and recovery treatments were followed by measuring CO2 exchange and chlorophyll fluorescence at 77K and 692 nm. CAP both exacerbated photoinhibition and blocked recovery for at least 150 min, especially at high temperatures. The close conformation of these two effects affirm that photoinhibition and recovery occur concomitantly. There was no apparent effect of CAP on the xanthophyll cycle, either during photoinhibition or recovery, indicating that zeaxanthin-mediated non-radiative energy (thermal) dissipation was unaffected by CAP. Because the CAP-induced increase in photoinhibition was not matched by an increase in the ratio of zeaxanthin to violaxanthin and antheraxanthin, the capacity of this photoprotective mechanism was apparently saturated. The primary effect of CAP on chlorophyll fluorescence was to affect Fm, the maximum fluorescence. There was only a minor effect on the initial fluorescence, Fo, during the photoinhibition and recovery treatments. The calculation of the rate constants for non-radiative dissipation (kD) and photochemistry (kp) from the fluorescence measurements indicated that an increase in kD occurred during high-light exposures and this was stimulated by CAP. However, since zeaxanthin was not mediating this, an alternative quencher in kiwifruit leaves, perhaps damaged PSII centres, is proposed. This would be consistent with an increased inactivation of PSII, as indicated by the changes in kp.

Nucleation of Disorder in Fe3Al Alloys

1967 ◽  
Vol 25 ◽  
pp. 312-313
Author(s):  
P. R. Swann ◽  
W. R. Duff ◽  
R. M. Fisher
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Annealing Temperature ◽  
Antiphase Domain ◽  
Effect Of Temperature ◽  
Domain Structures ◽  
Transmission Electron ◽  
Domain Boundaries ◽  
Higher Temperature ◽  
The One

Recently we have investigated the phase equilibria and antiphase domain structures of Fe-Al alloys containing from 18 to 50 at.% Al by transmission electron microscopy and Mössbauer techniques. This study has revealed that none of the published phase diagrams are correct, although the one proposed by Rimlinger agrees most closely with our results to be published separately. In this paper observations by transmission electron microscopy relating to the nucleation of disorder in Fe-24% Al will be described. Figure 1 shows the structure after heating this alloy to 776.6°C and quenching. The white areas are B2 micro-domains corresponding to regions of disorder which form at the annealing temperature and re-order during the quench. By examining specimens heated in a temperature gradient of 2°C/cm it is possible to determine the effect of temperature on the disordering reaction very precisely. It was found that disorder begins at existing antiphase domain boundaries but that at a slightly higher temperature (1°C) it also occurs by homogeneous nucleation within the domains. A small (∼ .01°C) further increase in temperature caused these micro-domains to completely fill the specimen.

The effect of temperature on high-resolution TEM image contrast

1995 ◽  
Vol 53 ◽  
pp. 640-641
Author(s):  
T. Geipel ◽  
W. Mader ◽  
P. Pirouz
Keyword(s):  
Form Factor ◽  
Inelastic Scattering ◽  
Accurate Method ◽  
Waller Factor ◽  
Effect Of Temperature ◽  
Specimen Thickness ◽  
Influence Of Temperature ◽  
Debye Waller Factor ◽  
Influence Of Temperature On ◽  
Atomic Form Factor

Temperature affects both elastic and inelastic scattering of electrons in a crystal. The Debye-Waller factor, B, describes the influence of temperature on the elastic scattering of electrons, whereas the imaginary part of the (complex) atomic form factor, fc = fr + ifi, describes the influence of temperature on the inelastic scattering of electrons (i.e. absorption). In HRTEM simulations, two possible ways to include absorption are: (i) an approximate method in which absorption is described by a phenomenological constant, μ, i.e. fi; - μfr, with the real part of the atomic form factor, fr, obtained from Hartree-Fock calculations, (ii) a more accurate method in which the absorptive components, fi of the atomic form factor are explicitly calculated. In this contribution, the inclusion of both the Debye-Waller factor and absorption on HRTEM images of a (Oll)-oriented GaAs crystal are presented (using the EMS software.Fig. 1 shows the the amplitudes and phases of the dominant 111 beams as a function of the specimen thickness, t, for the cases when μ = 0 (i.e. no absorption, solid line) and μ = 0.1 (with absorption, dashed line).

The development of dormancy in bulblets of Lilium speciosum generated in vitro. II. The effect of temperature

1990 ◽  
Vol 80 (3) ◽  
pp. 431-436 ◽  
Author(s):  
Isabelle Delvallee ◽  
Annie Paffen ◽  
Geert-Jan De Klerk
Keyword(s):  
Effect Of Temperature ◽  
Lilium Speciosum
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