scholarly journals Photosynthesis by isolated chloroplasts. Inhibition by dl-glyceraldehyde of carbon dioxide assimilation

1972 ◽  
Vol 128 (5) ◽  
pp. 1147-1157 ◽  
Author(s):  
D. M. Stokes ◽  
D. A. Walker
Keyword(s):  
Carbon Dioxide ◽  
Carbon Assimilation ◽  
Photosynthetic Electron Transport ◽  
O2 Evolution ◽  
Appreciable Effect ◽  
Carbon Dioxide Assimilation ◽  
Photosynthetic Carbon ◽  
Photosynthetic Carbon Assimilation ◽  
Isolated Chloroplasts ◽  
Spinach Leaves

Photosynthetic carbon assimilation and associated CO2-dependent O2 evolution by chloroplasts isolated from pea shoots and spinach leaves is almost completely inhibited by 10mm-dl-glyceraldehyde. The inhibitor is without appreciable effect on photosynthetic electron transport, photophosphorylation, the carboxylation of ribulose 1,5-diphosphate or the reduction of 3-phosphoglycerate, but apparently blocks the conversion of triose phosphate into ribulose 1,5-diphosphate.

Effect of methyl viologen on slow secondary fluorescence kinetics associated with photosynthetic carbon assimilation in intact isolated chloroplasts

1985 ◽  
Vol 226 (1243) ◽  
pp. 237-247 ◽  
Keyword(s):  
Methyl Viologen ◽  
Carbon Assimilation ◽  
Pentose Phosphate ◽  
Induction Phase ◽  
Atp Production ◽  
Gramicidin D ◽  
Photosynthetic Carbon ◽  
Photosynthetic Carbon Assimilation ◽  
Isolated Chloroplasts ◽  
Secondary Fluorescence

Methyl viologen in catalytic amounts induces pronounced secondary kinetics in fluorescence in intact isolated chloroplasts performing photosynthetic carbon assimilation. These transient increases in fluorescence and oscillations were associated with the induction phase of O 2 evolution in a similar manner to the transient ‘shoulder’ detected previously (Z. G. Cerović, M. N. Sivak and D. A. Walker, Proc . R . Soc . Lond . B 220, 327–338 (1984)). Experiments with the addition of antimycin A and gramicidin D demonstrated that methyl viologen induced an increased ATP production linked to pseudocyclic electron transport. The adjustment of ATP and NADPH production to meet the requirements of the reductive pentose phosphate pathway during induction is thought to be the cause of the detected transients and oscillations in fluorescence.

Slow secondary fluorescence kinetics associated with the onset of photosynthetic carbon assimilation in intact isolated chloroplasts

1984 ◽  
Vol 220 (1220) ◽  
pp. 327-338 ◽  
Keyword(s):  
Carbon Assimilation ◽  
Assay Medium ◽  
Exponential Increase ◽  
Photosynthetic Carbon ◽  
Intact Chloroplasts ◽  
Dark Interval ◽  
Photosynthetic Carbon Assimilation ◽  
Isolated Chloroplasts ◽  
Fast Rates ◽  
Secondary Fluorescence

Experiments with carefully isolated, largely intact chloroplasts, capable of fast rates of CO 2 -dependent O 2 evolution, show that the fall in chlorophyll a fluorescence (from the early maxima reached immediately after illumination) is interrupted by a ‘shoulder’ which is associated with the exponential increase in the rate of O 2 evolution. The length of this induction period was increased by storage, by decreased temperature, by increased orthophosphate concentration in the assay medium or by the presence of D, L-glyceraldehyde. It could also be shortened by the addition of 3-phosphoglycerate or dihydroxyacetonephosphate. In each treatment the shoulder in fluorescence shifted so that the association with the period of exponential increase was maintained. When illumination was re-started after a short dark interval, induction was minimal and no shoulder could be discerned, but both the lag in the onset of O 2 evolution and the shoulder were restored when the chloroplasts were resuspended in fresh assay medium during the period of darkness. The relation between chlorophyll a fluorescence and the onset of photosynthetic carbon assimilation is discussed.

Some effects of CO 2 concentration and decreased O 2 concentration on induction fluorescence in leaves

1983 ◽  
Vol 217 (1209) ◽  
pp. 377-392 ◽  
Keyword(s):  
Steady State ◽  
Carbon Assimilation ◽  
Free Air ◽  
Photosynthetic Carbon ◽  
Probable Impact ◽  
Quenching Mechanisms ◽  
Photosynthetic Carbon Assimilation ◽  
Initial Peak ◽  
Secondary Fluorescence ◽  
Spinach Leaves

A procedure is described that permits spinach leaves to display secondary fluorescence kinetics when illuminated in air at 20 °C. The initial peak in chlorophyll a fluorescence is then followed by a fall to a quasi-steady state (S), a rise to a new peak (M) and a final fall to a terminal steady-state value (T). These kinetics can be modified by changing the periods of light and darkness before measurement. The M peak is abolished by exposure to CO 2 -free air and greatly modified by exposure to 5 % CO 2 . In 2% O 2 the period of darkness immediately before illumination needs to be lengthened if secondary kinetics are to be observed. The results are discussed in relation to the probable impact of photosynthetic carbon assimilation on fluorescence-quenching mechanisms.

Sign in / Sign up

Export Citation Format

Share Document