The influence of sugar synthesis and transport rates on bioenergetics and kinetics of higher plant photosynthesis.
We have obtained the theoretical dependences of stromal metabolite steady-state concentrations on external inorganic phosphate (P(i)) concentration. For this purpose, the theoretical model of photosynthesis, earlier described in [Ann. Appl. Biol. 138 (2001) 117], was modified to account for the regulation of starch formation by 3-phosphoglycerate (PGA) to P(i) ratio. When the rate constant of starch synthesis is taken to be independent on PGA/P(i) ratio, the steady-state concentrations of Calvin cycle metabolites and starch were found to change insignificantly as external P(i) concentration increases in wide range. However, as external P(i) range exceeds a critical value, the steady-state concentrations of all metabolites change abruptly. If the rate constant of starch synthesis depends on PGA/P(i) ratio, the steady-state concentrations of stromal metabolites change qualitatively in the same way with the increase of external P(i). However, no abrupt changes of metabolite and starch steady-state levels at high concentration of P(i) are observed. These results testify that the control of starch synthesis by PGA/P(i) ratio makes the photosynthetic system more stable in wide range of external P(i) concentrations.
Tuleshova
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A
Faculty of Physics, Moscow State University, Vorobjevy Gory, 119899 Moscow, Russia. Nastya@bio471b.phys.msu.su
Badretdinov
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D
Kukushkin
A
A
Khuznetsova
S
S
D001692:Biological Transport; D002241:Carbohydrates / Q000096:biosynthesis*; D004734:Energy Metabolism; D007700:Kinetics; D010788:Photosynthesis; D018521:Plant Physiological Phenomena
D002241:Carbohydrates