Effect of high light intensities on oxygen evolution and the light activation of NADP-malate dehydrogenase in intact spinach chloroplasts

Planta ◽  
1988 ◽  
Vol 173 (4) ◽  
pp. 468-473 ◽  
Author(s):  
M. Miginiac-Maslow ◽  
G. Cornic ◽  
J. -P. Jacquot
Keyword(s):  
Malate Dehydrogenase ◽  
Oxygen Evolution ◽  
High Light ◽  
Light Activation ◽  
Spinach Chloroplasts ◽  
Light Intensities

Influence of Environmental Factors on the Light Activation of Pyruvate, PI Dikinase and NADP-Malate Dehydrogenase in Maize

1983 ◽  
Vol 10 (3) ◽  
pp. 279 ◽  
Author(s):  
H Nakamoto ◽  
GE Edwards
Keyword(s):  
Environmental Factors ◽  
Malate Dehydrogenase ◽  
Disulfide Bonds ◽  
Adenine Nucleotides ◽  
High Light ◽  
Light Activation ◽  
Anaerobic Conditions ◽  
Low Light ◽  
Fold Stimulation

The interaction among several environmental factors on the degree of light activation of NADP- malate dehydrogenase (MDH, EC 1.1.1.82) and pyruvate,PI dikinase (EC 2.7.9.1) in the C4 plant maize was determined. At 25°C under limiting light (50 �E m-2 s-1), there was a several-fold stimulation in the degree of activation of both enzymes when CO2 was removed from the atmosphere. Under high light (1000 �E m-2 s-1), CO2 did not influence the degree of activation of the enzymes. At 25°C under limiting light in the absence of CO2, the degree of activation of NADP-MDH increased as O2 was reduced below 21% with maximum activation occurring under anaerobic conditions. O2 had little or no effect on the degree of activation of NADP-MDH under high light. In contrast, with pyruvate,PI dikinase at 25°C and in the absence of CO2, anaerobic conditions strongly inhibited the degree of activation of the enzyme under low or high light, while under aerobic conditions the enzyme was activated to the same extent under 2 or 21% O2. The inhibition of activation of the dikinase under anaerobic conditions was partially relieved by addition of atmospheric levels (0.03%) of CO2. In contrast to the results at 25°C, the presence or absence of CO2 or O2 at 10°C under low light had little or no effect on the activation of the two enzymes. The results are evaluated in relation to previous in vitro studies which suggest activation of NADP- MDH by reduction of disulfide bonds on the enzyme and activation of pyruvate,PI dikinase by changes in adenine nucleotides.

Light-activation of NADP-malate dehydrogenase: A highly controlled process for an optimized function

2000 ◽  
Vol 110 (3) ◽  
pp. 322-329 ◽  
Author(s):  
M. Miginiac-Maslow ◽  
K. Johansson ◽  
E. Ruelland ◽  
E. Issakidis-Bourguet ◽  
I. Schepens ◽  
...  
Keyword(s):  
Malate Dehydrogenase ◽  
Light Activation

H 2 production in Rhodopseudomonas palustris as a way to cope with high light intensities

2016 ◽  
Vol 167 (5) ◽  
pp. 350-356 ◽  
Author(s):  
Dayana Muzziotti ◽  
Alessandra Adessi ◽  
Cecilia Faraloni ◽  
Giuseppe Torzillo ◽  
Roberto De Philippis
Keyword(s):  
Rhodopseudomonas Palustris ◽  
High Light ◽  
Light Intensities

scholarly journals Light intensity regulates phototaxis, foraging and righting behaviors of the sea urchin Strongylocentrotus intermedius

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e8001 ◽  
Author(s):  
Jiangnan Sun ◽  
Xiaomei Chi ◽  
Mingfang Yang ◽  
Jingyun Ding ◽  
Dongtao Shi ◽  
...  
Keyword(s):  
Light Intensity ◽  
Foraging Behavior ◽  
Sea Urchins ◽  
High Light Intensity ◽  
High Light ◽  
Strongylocentrotus Intermedius ◽  
Low Light ◽  
Low Light Intensity ◽  
Light Intensities ◽  
Significant Difference

Small sea urchins Strongylocentrotus intermedius (1–2 cm of test diameter) are exposed to different environments of light intensities after being reseeded to the sea bottom. With little information available about the behavioral responses of S. intermedius to different light intensities in the environment, we carried out an investigation on how S. intermedius is affected by three light intensity environments in terms of phototaxis, foraging and righting behaviors. They were no light (zero lx), low light intensity (24–209 lx) and high light intensity (252–2,280 lx). Light intensity had obvious different effects on phototaxis. In low light intensity, sea urchins moved more and spent significantly more time at the higher intensity (69–209 lx) (P = 0.046). S. intermedius in high light intensity, in contrast, spent significantly more time at lower intensity (252–690 lx) (P = 0.005). Unexpectedly, no significant difference of movement (average velocity and total distance covered) was found among the three light intensities (P > 0.05). Foraging behavior of S. intermedius was significantly different among the light intensities. In the no light environment, only three of ten S. intermedius found food within 7 min. In low light intensity, nine of 10 sea urchins showed successful foraging behavior to the food placed at 209 lx, which was significantly higher than the ratio of the number (two of 10) when food was placed at 24 lx (P = 0.005). In the high light intensity, in contrast, significantly less sea urchins (three of 10) found food placed at the higher light intensity (2,280 lx) compared with the lower light intensity (252 lx) (10/10, P = 0.003). Furthermore, S. intermedius showed significantly longer righting response time in the high light intensity compared with both no light (P = 0.001) and low light intensity (P = 0.031). No significant difference was found in righting behavior between no light and low light intensity (P = 0.892). The present study indicates that light intensity significantly affects phototaxis, foraging and righting behaviors of S. intermedius and that ~200 lx might be the appropriate light intensity for reseeding small S. intermedius.

Stomatal aperture can compensate altered stomatal density in Arabidopsis thaliana at growth light conditions

2006 ◽  
Vol 33 (11) ◽  
pp. 1037 ◽  
Author(s):  
Dirk Büssis ◽  
Uritza von Groll ◽  
Joachim Fisahn ◽  
Thomas Altmann
Keyword(s):  
Arabidopsis Thaliana ◽  
Stomatal Conductance ◽  
Stomatal Density ◽  
Co2 Assimilation ◽  
High Light ◽  
Stomatal Aperture ◽  
Photochemical Quenching ◽  
Light Conditions ◽  
Wild Type ◽  
Light Intensities

Stomatal density of transgenic Arabidopsis thaliana plants over-expressing the SDD1 (stomatal density and distribution) gene was reduced to 40% and in the sdd1-1 mutant increased to 300% of the wild type. CO2 assimilation rate and stomatal conductance of over-expressers and the sdd1-1 mutant were unchanged compared with wild types when measured under the light conditions the plants were exposed to during growth. Lower stomatal density was compensated for by increased stomatal aperture and conversely, increased stomatal density was compensated for by reduced stomatal aperture. At high light intensities the assimilation rates and stomatal conductance of SDD1 over-expressers were reduced to 80% of those in wild type plants. Areas beneath stomata and patches lacking stomata were analysed separately. In areas without stomata, maximum fluorescence yield (Fv / Fm) and quantum yield of photosystem II (Φ PSII) were significantly lower than in areas beneath stomata. In areas beneath stomata, Fv / Fm and Φ PSII were identical to levels measured in wild type leaves. At high light intensities over-expressers showed decreased photochemical quenching (qP) compared with wild types. However, the decrease of qP was significantly stronger in areas without stomata than in mesophyll areas beneath stomata. At high CO2 partial pressures and high light intensities CO2 assimilation rates of SDD1 over-expressers did not reach wild type levels. These results indicate that photosynthesis in SDD1 over-expressers was reduced because of limiting CO2 in areas furthest from stomata at high light.

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