scholarly journals Net photosynthetic O2 evolution and calcium precipitation in Chlamydomonas reinhardtii

2006 ◽  
Author(s):  
Y. Y. Wu ◽  
P. P. Li ◽  
B. L. Wang ◽  
C. Q. Liu
Keyword(s):  
Chlamydomonas Reinhardtii ◽  
O2 Evolution ◽  
Photosynthetic O2 Evolution ◽  
Calcium Precipitation

Photosynthetic O2 evolution and apparent H+ uptake by slices of greening barley and maize leaves in aerobic and anaerobic solutions

1973 ◽  
Vol 51 (10) ◽  
pp. 1953-1957 ◽  
Author(s):  
Ulrich Lüttge
Keyword(s):  
Bundle Sheath ◽  
O2 Evolution ◽  
Strictly Anaerobic ◽  
Ph Change ◽  
Reaction Systems ◽  
Gas Streams ◽  
Maize Leaves ◽  
Photosynthetic O2 Evolution ◽  
Varied Composition ◽  
Aerobic And Anaerobic

Apparent rates of photosynthetic O2 evolution and light-dependent pH change (Δ[H+]) were measured in solutions containing leaf slices and bubbled with gas streams of varied composition. Intracellular recycling of O2 and CO2 between photosynthetic and respiratory reaction systems seems to be possible in green cells in the light. As a result of photosynthetic O2 evolution, the tissue and the solution are never strictly anaerobic even after prolonged bubbling with N2. Internal gas exchange is more pronounced in slices from the leaves of maize (a C-4 plant) having the complex Kranz tissue differentiation of mesophyll and bundle sheath, than in the leaves of barley (a C-3 plant).Light-dependent Δ[H+] is observed under all conditions used, i.e. in air, air – CO2, pure N2, and N2 + CO2. During the early stages of greening of etiolated leaves, Δ[H+] is found to be closely related to photosynthetic O2 evolution. After prolonged greening, Δ[H+] is larger in air – CO2 than in air. In pure N2, Δ[H+] is smaller and apparent O2 evolution is larger than in N2 + CO2. These results are discussed in relation to the hypothesis that part of light-dependent Δ[H+] is independent of concomitant photosynthetic CO2 fixation.

scholarly journals Mechanism for photosynthetic O2 evolution.

1986 ◽  
Vol 83 (13) ◽  
pp. 4586-4588 ◽  
Author(s):  
G. W. Brudvig ◽  
R. H. Crabtree
Keyword(s):  
O2 Evolution ◽  
Photosynthetic O2 Evolution

Submergence of Rice. I. Growth and Photosynthetic Response to CO2 Enrichment of Floodwater

1989 ◽  
Vol 16 (3) ◽  
pp. 251 ◽  
Author(s):  
TL Setter ◽  
I Waters ◽  
I Wallace ◽  
P Bhekasut ◽  
H Greenway
Keyword(s):  
Co2 Enrichment ◽  
Co2 Concentration ◽  
O2 Evolution ◽  
Photosynthetic Response ◽  
Submerged Plants ◽  
High Co2 ◽  
Low Co2 ◽  
O2 Concentration ◽  
Photosynthetic O2 Evolution ◽  
Rice Leaves

Growth and photosynthetic response of lowland rice following complete submergence is related to the concentration of CO2 dissolved in floodwater. Submergence of plants in stagnant solution at low CO2 concentration or solution gassed with air at 0.03 kPa CO2 (equilibrium of 0.01 mol m-3 dissolved CO2) decreased carbohydrates, and little or no growth occurred. Plants submerged in solutions gassed with 3-20 kPa CO2 in air (equilibrium of 0.9-6 mol m-3 CO2) showed at most small decreases in carbohydrates, and growth was up to 100% of the non-submerged plants. At pH 7.5, there was little net photosynthetic O2 evolution by detached submerged leaves even at high HCO3- concentrations, which suggests that these rice leaves could utilise only CO2 and not HCO3-. At pH 6.5, O2 evolution in solutions in equilibrium with 7.4 kPa CO2 was 3-4 fold higher than in solutions in equilibrium with 0.6 kPa CO2. Photorespiration was indicated by a decrease in the rate of net O2 evolution with increasing external O2. In stagnant solutions this reduction of O2 evolution was pronounced; at a CO2 concentration of 0.25 mol m-3 net O2 evolution ceased when the O2 concentration in the water had reached only 0.125 mol m-3. The requirement of photosynthesis for a combination of high CO2 concentrations and low external O2 was presumably due to slow diffusion of these gases in the unstirred layer of solution around the leaves.

Low temperature effects on grapevine photosynthesis: the role of inorganic phosphate

2004 ◽  
Vol 31 (8) ◽  
pp. 789 ◽  
Author(s):  
Luke Hendrickson ◽  
Wah Soon Chow ◽  
Robert T. Furbank
Keyword(s):  
Low Temperature ◽  
Carbon Assimilation ◽  
O2 Evolution ◽  
Vitis Vinifera L ◽  
Regulatory Processes ◽  
Photosynthetic O2 Evolution ◽  
Grapevine Leaves ◽  
Sugar Levels ◽  
Stimulation Of

The photosynthetic response of grapevine leaves (Vitis vinifera L. cv. Riesling) to low temperature was studied to determine the role of end-product limitation and orthophosphate (Pi) recycling to the chloroplast under these conditions. As reported previously, the response of photosynthesis in air to stomatal conductance declined at temperatures below 15°C, suggesting that at low temperatures inhibition of photosynthesis in grapevine has a strong non-stomatal component. Stimulation of carbon assimilation at ambient CO2 by reducing O2 from 21 to 2 kPa, O2 declined to zero below 15°C, a phenomenon often associated with a restriction in photosynthesis due to end-product-synthesis limitation. This stimulation could be restored by feeding Pi. Photosynthesis in leaf disks at both high and low irradiances in non-photorespiratory conditions (1% CO2) was highly sensitive to reductions in temperature. Below 15°C, feeding Pi caused a large stimulation of photosynthetic O2 evolution. Metabolite measurements indicated that despite a decline in Rubisco carbamylation state, ribulose 1,5-bisphosphate (RuBP) levels dropped at low temperature and the ratio of 3-phosphoglycerate (3-PGA) to triose phosphate (TP) remained largely unchanged. These results suggest that grapevine-leaf photosynthesis is severely restricted at low temperature by non-stomatal mechanisms. The return of Pi to the chloroplast plays an important role in this limitation but a coordinated set of regulatory processes maintain a homeostasis of phosphorylated sugar levels.

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