Carbohydrate metabolism, in plants

The individual pathways of carbohydrate metabolism in plants overlap extensively they share pools of common intermediates, including hexose phosphates, pentose phosphates, and triose phosphates. Transporters in the membranes of chloroplasts, mitochondria, amyloplasts, and peroxisomes mediate the movement of sugar phosphates between organelles. The direction of metabolite flow through the pools changes from day to night. 

Potassium [7440-09-7], K, is the third element in the alkali metal series. The name designation for the element is derived from potash, a potassium mineral the symbol from the German name kalium, which comes from the Arabic qili, a plant. The ashes of these plants (a/ qih) were the historical source of potash for preparing fertilizers (qv) or gun powder. Potassium ions, essential to plants and animals, play a key role in carbohydrate metabolism in plants. In animals, potassium ions promote glycolysis, lipolysis, tissue respiration, and the synthesis of proteins (qv) and acetylcholine. Potassium ions are also believed to function in regulating blood pressure. 

From this brief survey, it is seen that there were few features of carbohydrate metabolism in plants that escaped Hassid s touch, and much that we now know about the role of sugar nucleotides in the interconversion of carbohydrates in plants is a direct result of his persistent effort. From the incorporation of labelled precursors into monosaccharides, to the conversion of the monosaccharides into their glycosyl phosphates, to the action of the pyrophosphorylases in the synthesis of glycosyl esters of nucleoside pyrophosphates, to the interconversion of the resulting sugar nucleotides, to the polymerization of the activated monosaccharides to yield disaccharides and the homopolysaccharides, and, finally, to the modification of the polysaccharides by methylation—in summary, to almost every aspect... 

L21. Loewus, F. A., Finkle, B. J., and Jang, R., L-Ascorbic acid a possible intermediate in carbohydrate metabolism in plants. Biochim. et Biophys. Acta 30, 629-635 (1958). 

Duffus C M and Duffus J H 1984 Carbohydrate Metabolism in Plants, London, Longman. 

Barton, D. and Ollis, W. D. (1979) Comprehensive Organic Chemistry The Synthesis and Reactions of Organic Compounds, Vol. 5, Biological Compounds, E. Haslara (ed.), Pergamon, Oxford Duffus, C. M. and Duffus, J. H. (1984) Carbohydrate Metabolism in Plants, Longman, London... 

CN204 Lai, J. ]., C. V. Kumar, M. V. Suresh, M. Indira, and P. L. Vijayammal. Effect of coconut palm wine (Toddy) on carbohydrate metabolism in pregnant rats and fetuses. Plant Foods Hum Nutr 1997 50(1) 71-79. 

Carbohydrate metabolism in a typical plant cell is more complex in several ways than that in a typical animal cell. The plant cell carries out the same processes that generate energy in animal cells (glycolysis, citric acid cycle, and oxidative phosphorylation) it can generate hexoses from three- or four-carbon compounds by glu-coneogenesis it can oxidize hexose phosphates to pentose phosphates with the generation of NADPH (the ox-... 

SUMMARY 20.5 Integration of Carbohydrate Metabolism in the Plant Cell... 

The neutral and nonspecific FDPases may function in nonphotosynthetic carbohydrate metabolism in higher plants. In the germinating castor bean acetate is utilized for the synthesis of sucrose 107, 108), and the presence of the AMP-sensitive FDPase in plant embryo tissues has been demonstrated by Bianchetti and Satirana 109). The changes in levels of this enzyme in response to changes in physiological conditions 109) support a gluconeogenic role for this enzyme. The role of the nonspecific acid FDPase in plant tissues remains unknown. 

Mbaku, S. B., Fritz, G. J., and Bowes, G. 1978. Photosynthetics and carbohydrate metabolism in isolated leaf cells of Digitaria pentzii. Plant Physiol. 62, 510-515. 

Fernie, A.R. Willmitzer, L. Carbohydrate metabolism. In Handbook of Plant Biotechnology, Christou, P., Klee, H., Eds. John Wiley Sons, Ltd. Chichester, U.K., 2004 525-557. 

B5. Barker, J., and Mapson, L. W., Studies in the respiratory and carbohydrate metabolism of plant tissues. VII. Experimental studies with potato tubers of an inhibition of the respiration and of a block in the tricarboxylic acid cycle induced by oxygen poisoning. Proc. Roy. Soc. B143, 523-549 (1955). 

T6. Turner, E. R., and Quartley, C. E., Studies in the respiratory carbohydrate metabolism of plant tissues. VIII. An inhibition of respiration in peas induced by oxygen poisoning. J. Exptl. Botany 7, 362-371 (1956). 

G. Bianchi, A. Gamba, C. Murelli, F. Salamini, and D. Bartels, Novel carbohydrate metabolism in the resurrection plant Craterostigma plantagineum, The Plant Journal, 1 (1991) 335-339. 

M. Norwood, M. R. Truesdale, A. Richter, and P. Scott, Photosynthetic carbohydrate metabolism in the resurrection plant Craterostigma plantagineum, J. Exp. Botany, 51 (1995) 159-165. 

Cytokinins play a central role in the regulation of fruit set in many multi-fruited species. Because of their primary site of synthesis in the roots, this provides a mechanism for the plant to maintain fruit load consistent with the plant s ability to produce viable seed based on such important soil conditions as fertility and water availability. The complete mechanism by which cytokinins induce development of fertilized ovaries is unknown, but carbohydrate metabolism in the ovary is one process involved. The cytokinins have the ability to promote carbohydrate metabolism and associated sink strength of the ovary by enhancing the level of the regulator F-2,6-bP. How cytokinins cause modulation of F-2,6-bP levels, and what other metabolic or molecular processes are involved are further questions to be answered. In a general sense, cytokinins act as metabolic stimulants of fertilized ovaries which have become quiescent, and, as such, induce their full development into mature seed-bearing fruit. 

Schrader S. and Sauter J.J. 2002. Seasonal changes of sucrose-phosphate synthase and sucrose synthase activities in poplar wood (Populm x Canadensis Moench robusta) and their possible role in carbohydrate metabolism. J Plant Physiol 159 833-843. 

Briggs, D.E. Hormones and carbohydrate metabolism in germinating cereal grains. In Biosynthesis and Its Control in Plants. Milborrow, B.V. (ed.). London Academic Press, 1973, pp. 219-277... 

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