scholarly journals The Mechanism of the Photochemical Activity of Isolated Chloroplasts. III. Dependence of Velocity on Light Intensity.

1959 ◽  
Vol 34 (3) ◽  
pp. 293-300 ◽  
Author(s):  
John S. Rieske ◽  
Rufus Lumry ◽  
John D. Spikes
Keyword(s):  
Light Intensity ◽  
Photochemical Activity ◽  
Isolated Chloroplasts

Development of Photochemical Activity in Chloroplast Membranes. II. Studies With a Mutant of Barley Grown Under Different Environments

1977 ◽  
Vol 4 (3) ◽  
pp. 439 ◽  
Author(s):  
RM Smillie ◽  
NC Nielsen ◽  
KW Henningsen ◽  
DV Wettstein
Keyword(s):  
Light Intensity ◽  
Developmental Stages ◽  
Chloroplast Development ◽  
Nuclear Gene ◽  
Photochemical Activity ◽  
Hordeum Vulgare L ◽  
Chloroplast Membranes ◽  
Photochemical Activities ◽  
Gene Mutant ◽  
Isolated Chloroplasts

Chloroplast development in the barley mutant xantha-b12, a nuclear gene mutant derived from Hordeum vulgare L. cv. Sval�fs Bonus, was profoundly influenced by the temperature and light intensity to which the plants were subjected during growth. Low temperatures and high light intensities retarded chloroplast development. By growing this mutant under different combinations of temperature and light intensity, seedlings were produced containing chloroplasts at different developmental stages. Measurements of photochemical activities of the isolated chloroplasts indicated a sequence for development of photochemical competence in chloroplast membranes very similar to that adduced from a study of several different barley mutants grown under a single environment. A photoreductive capacity is initially acquired but energy conservation sites only become fully functional at an advanced stage of membrane development.

Inhibition by Cyanide of the Photochemical Activity of Isolated Chloroplasts

Nature ◽  
1955 ◽  
Vol 176 (4476) ◽  
pp. 307-308 ◽  
Author(s):  
NORMAN I. BISHOP ◽  
JOHN D. SPIKES
Keyword(s):  
Photochemical Activity ◽  
Isolated Chloroplasts

Light Saturation of Growth and Photosynthesis of the Shade Plant Marchantia Polymorpha

1973 ◽  
Vol 12 (2) ◽  
pp. 391-401
Author(s):  
R. MACHE ◽  
S. LOISEAUX
Keyword(s):  
Growth Rate ◽  
Photosystem Ii ◽  
Light Intensity ◽  
Marchantia Polymorpha ◽  
Hill Reaction ◽  
Light Saturation ◽  
Shade Plant ◽  
Low Illumination ◽  
The Hill ◽  
Isolated Chloroplasts

The growth rate of the shade plant Marchantia was at its maximum for a low illumination, 2-3 x 103 lx, and was inhibited by an excess of light. Photosynthesis by intact thalli and by isolated chloroplasts of Marchantia was saturated by a light intensity of 2-3 x 103 lx. These isolated chloroplasts were able to carry on satisfactory rates of photosynthesis, up to 35 µM CO2/h/mg chlorophyll. The Hill reaction and photosystem II were also saturated by the same light intensities, demonstrating that the factor limiting the light saturation of photosynthesis is located in the chloroplast. The structure of chloroplasts was strongly modified by an excess of light, small grana and fret membranes being replaced by continuous grana.

Effects of aging on chlorophyll fluorescence and photosystem II electron transport in isolated chloroplasts

1975 ◽  
Vol 53 (23) ◽  
pp. 2842-2845 ◽  
Author(s):  
M. Fragata
Keyword(s):  
Fatty Acids ◽  
Chlorophyll Fluorescence ◽  
Photosystem Ii ◽  
Conformational Changes ◽  
Photochemical Activity ◽  
Photosynthetic Membrane ◽  
Fluorescence Characteristics ◽  
Protein Molecules ◽  
Effects Of Aging ◽  
Isolated Chloroplasts

The correlation between emission of energy and photochemical activity in isolated chloroplasts during aging was investigated. It was shown that aging hinders the intensity of chlorophyll-a fluorescence with a concomitant decrease of the photosystem II activity. In view of the parallelism between the action of exogenous fatty acids, especially C18-unsaturated acids, and the effects of aging, it is suggested that the thylakoid transformation during aging could result partly from conformational changes of the membrane polypeptides due to the presence of free fatty acids in the neighborhood of the protein molecules. It is possible that such a mechanism of fatty acid action may alter the fluorescence characteristics of chlorophyll as well as the tunneling of electrons in the photosynthetic membrane.

Spectrophotometric Isolation of Kinetically Different Pools of P-700 and Their Correlation to the Reduction of NADP by Isolated Chloroplasts *. I. The Effect of Light Quality and Intensity

1982 ◽  
Vol 37 (1-2) ◽  
pp. 31-39 ◽  
Author(s):  
Hans J. Rurainski ◽  
Richard Gerhardt ◽  
Gerhard Mader
Keyword(s):  
Light Intensity ◽  
Spectral Characteristics ◽  
Red Light ◽  
Relaxation Times ◽  
Relative Magnitude ◽  
Molar Ratio ◽  
Experimental Conditions ◽  
Turn Over ◽  
Isolated Chloroplasts ◽  
Total P

Excitation of isolated chloroplasts in the presence of ferredoxin and NADP by repeated short flashes yields a polyphasic absorption change at 700 nm. Assuming first-order reactions, the signal may be resolved into three distinct components with average relaxation times of approxi­mately 20 μs, 150 μs and 20 ms. Their relative magnitude is dependent on experimental conditions; their spectral characteristics indicate that all three components may be ascribed to P-700. Concurrent measurements of Y-NADPH, the flash yield of NADP reduction with an enzymatic recycling method, allowed Y-NADPH to be compared to the magnitude of each of the three P-700 components and to total P-700. In general, the data show a good correlation of NADP reduction with the sum of the μs-phases but not with the ms-phase or total P-700. Analysis of light intensity curves (blue or far red flashes) with a mathematical model which yields maximum values for all parameters at infinite light intensity shows that in both cases approximately two moles of the microsecond component of P-700 turn over for each mole of NADPH formed. In contrast, the molar ratio of the ms-component to the yield of NADP reduction is approx. 0.2 in blue and approx. 6.3 in far red light. The data suggest that only that portion of the P-700 pool which relaxes in the microsecond range may be involved in the reduction of NADP while the ms-component is funtionally isolated from linear electron transport.

Inhibition of Photochemical Activity of Isolated Chloroplasts by Acylanilides

Weeds ◽  
1963 ◽  
Vol 11 (1) ◽  
pp. 55 ◽  
Author(s):  
D. E. Moreland ◽  
K. L. Hill
Keyword(s):  
Photochemical Activity ◽  
Isolated Chloroplasts
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