Effect of Substrate Salinity on the Ability for Protein Synthesis in Pea Roots

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Abstract
The contribution of the reductive pentose phosphate cycle to the photometabolism of carbon dioxide and to carbon metabolism in Rhodospirillum rubrum grown photoheterotrophically with l-malate as the carbon source is nil, unlike autotrophically grown R. rubrum. Glycolic acid appears to be the first stable product of CO2 fixation in R. rubrum cultured photoheterotrophically on l-malate. The results obtained in 14CO2 fixation experiments suggest that the photometabolism of CO2 through glycolate into malate is a major pathway of CO2 fixation in such cells. However, l-malate was a much more efficient precursor of phosphate esters, and of glutamic acid, than was carbon dioxide; l-malate is therefore, in this case, a far more important source of cell carbon than is carbon dioxide.