An Analytical Model of Photosynthetic Response of Aquatic Plants to Inorganic Carbon and pH

Ecology ◽  
1981 ◽  
Vol 62 (3) ◽  
pp. 697-705 ◽  
Author(s):  
J. A. Weber ◽  
J. D. Tenhunen ◽  
S. S. Westrin ◽  
C. S. Yocum ◽  
D. M. Gates
Keyword(s):  
Analytical Model ◽  
Aquatic Plants ◽  
Inorganic Carbon ◽  
Photosynthetic Response

scholarly journals Increase of 14C Activity of Dissolved Inorganic Carbon Along a River Course

Radiocarbon ◽  
1986 ◽  
Vol 28 (2A) ◽  
pp. 515-521 ◽  
Author(s):  
Dušan Srdoč ◽  
Ines Krajcar-Bronić ◽  
Nada Horvatinčić ◽  
Bogomil Obelić
Keyword(s):  
Aquatic Plants ◽  
Water Samples ◽  
Organic Material ◽  
Root Respiration ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Stream Water ◽  
Exchange Process ◽  
Karst Spring ◽  
Stream Waters

Results of measurements for 3 years (1981–1983) of 14C activity of dissolved inorganic carbon (DIG) in water samples from the Korana River, as well as that of recent tufa and aquatic plants, showed that 14C concentration increases from karst spring to the estuary. A model describing the increase of 14C activity was developed assuming that the increase is due to the exchange of the dissolved CO2 in stream water with atmospheric CO2 and to dissolution of CO2 from the decay of organic material and root respiration. It is possible to distinguish these two contributions by measuring the δ13C values of DIC in water. As expected, our data show that the exchange process between atmospheric CO2 and DIC dominates at rapids and waterfalls, while biologic contribution is much higher in lakes and along the lowland flow of the Korana River. Agreement between the calculated and the measured activities supports the proposed mechanisms of chemical and isotopic exchanges in stream waters.

THE ACQUISITION OF INORGANIC CARBON IN MARINE MACROPHYTES

1998 ◽  
Vol 46 (2) ◽  
pp. 83-87 ◽  
Author(s):  
Sven Beer
Keyword(s):  
Carbonic Anhydrase ◽  
Aquatic Plants ◽  
Inorganic Carbon ◽  
External Medium ◽  
Uptake Mechanism ◽  
Tropical Regions ◽  
Marine Macrophytes ◽  
Photosynthetic Carbon ◽  
Diffusion Rates ◽  
Carbon Transport

The low diffusion rates of solutes in water call for a separation of photosynthetic carbon acquirement in aquatic plants into carbon transport and the subsequent photosynthetic reduction of CO2. This paper will focus on the transport of inorganic carbon from the external medium to the site of fixation in marine macrophytes. In accord with the much higher concentration of HCO3− than of CO2 in seawater, most marine macrophytes can utilize the ionic carbon form for their photosynthetic needs. The two known ways of HCO, utilization are (a) via extracellular, carbonic anhydrase catalyzed dehydration of HCO3− to form CO2, which then diffuses into the photosynthesizing cells, and (b) by direct uptake via a transporter. While the first way may be sufficient to support low rates of photosynthesis in temperate regions, it is viewed as futile under situations where high temperatures and irradiances would cause a high pH to form close to the uptake site of carbon and where, consequently, the CO2/HCO3− ratio would be very low. Therefore, it may well be that the direct HCO3− uptake mechanism described for Ulva from more tropical regions confers an adaptational advantage under conditions conducive to higher photosynthetic rates.

scholarly journals Carbon Uptake in Aquatic Plants Deduced From Their Natural 13C and 14C Content

Radiocarbon ◽  
1989 ◽  
Vol 31 (03) ◽  
pp. 785-794 ◽  
Author(s):  
Elena Marčenko ◽  
Dušan Srdoč ◽  
Stjepko Golubić ◽  
Jože Pezdič ◽  
M J Head
Keyword(s):  
Carbon Source ◽  
Aquatic Plants ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Natural Habitat ◽  
Terrestrial Plants ◽  
Activity Measurements ◽  
Aquatic Mosses ◽  
Age Correction ◽  
Karst Waters

δ13C and 14C activity measurements were made on terrestrial, marsh and aquatic plants growing in their natural habitat of the Plitvice Lakes in northwest Yugoslavia. δ13C values were ca −47 for aquatic mosses, which indicate that the carbon source was dissolved inorganic carbon (DIC) from alkaline karst waters, following a C3 pathway, and ca −25 for marsh plants, indicating the carbon source was atmospheric CO2. 14C activity of true aquatic plants and submerged parts of helophytes was close to 14C activity of DIC, whereas that of emergent parts of helophytes and terrestrial plants was similar to atmospheric CO2 activity. Aquatic plants which use DIC in freshwater for their photosynthesis are not suitable for 14C dating, unless the initial activity of incorporated carbon is known. δ13C values of plant material also depend on the carbon source and cannot be used for 14C age correction.

Inhibition by Proton Buffers of Photosynthetic Utilization of Bicarbonate in Chara corallina

1985 ◽  
Vol 12 (3) ◽  
pp. 257 ◽  
Author(s):  
G.D Price ◽  
M.R Badger
Keyword(s):  
Experimental Data ◽  
Simple Model ◽  
Inorganic Carbon ◽  
Chara Corallina ◽  
Bulk Phase ◽  
Initial Slope ◽  
Photosynthetic Response ◽  
Acidic Compartment ◽  
Rate Limiting

A simple model was developed to explain the mechanism by which buffers inhibit HCO*3� utilization in Chara corallina. The chief assumption was that an acidic compartment exists in the peiiplasmic space and that exogenous buffer species must cross the apoplast to dissipate this H+ gradient (�pH). Assuming that HCO*3� utilization depends on H+ extrusion, buffer-induced H+ dissipation should result in a reduction in inorganic carbon (C*i) limited photosynthesis. The model predicts that buffers with a pKa midway between the bulk phase pH (pHo) and an assumed periplasmic pH will be most effective in dissipating the periplasmic �pH. Experiments conducted at pHo = 9.3 and with 5 mM concentrations of various buffers show that buffers in the range pKa 7.5-9.0 are most inhibitory to HCO*3� utilization. The initial slope of the photosynthetic response to C*i (i.e. where C*i availability is rate limiting) is more sensitive to buffers than rates at high C*i levels. Buffer inhibition was reversible. Experimental data correspond well with the model and indicate that HCO*3� utilization sites in the periplast are considerably more acidic than the bulk phase during photosynthetic HCO*3� utilization. Results suggest that during buffer inhibition experiments �pH is around 2 or more units when the bulk phase pH is 9.3.

Photosynthetic response of P-deficient Gracilaria tenuistipitata under two different phosphate treatments

1996 ◽  
Vol 96 (4) ◽  
pp. 601-606 ◽  
Author(s):  
Maria J. Garcia-Sanchez ◽  
Jose A. Fernandez ◽  
F. Xavier Niell
Keyword(s):  
Photosynthetic Response ◽  
Gracilaria Tenuistipitata
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