Abstract
Activities of key enzymes of Calvin cycle and C4 metabolism, rate of 14CO2 fixation in light and dark and the initial products of photosynthetic 14CO2 fixation were determined in flag leaf and different ear parts of wheat viz. pericarp, awn and glumes. Compared to the activities of RuBP carboxylase and other Calvin cycle enzymes viz. NADP-glyceraldehyde-3-phosphate dehydrogenase, NAD-glyceraldehyde-3-phosphate dehydrogenase and ribulose-5-phosphate kinase, the levels of PEP carboxylase and other enzymes of C4 metabolism viz. NADP-malate dehydrogenase, NAD-malate dehydrogenase, NADP-malic enzyme, NAD-malic enzyme, glutamate oxaloacetate transaminase genase, NADP-malic enzyme, NAD-malic enzyme, glutamate oxaloacetate transaminase and glutamate pyruvate transaminase, were generally greater in ear parts than in the flag leaf. In contrast to CO2 fixation in light, the various ear parts incorporated CO2 in darkness at much higher rates than flag leaf. In short term assimilation of 14CO2 by illuminated ear parts, most of the 14C was in malate with less in 3-phosphoglyceric acid, whereas flag leaves incorporated most into 3-phosphoglyceric acid. It seems likely that ear parts have the capability of assimilating CO2 by the C4 pathway of photosynthesis and utilise PEP carboxylase for recapturing the respired CO2.
Article PDF
Similar content being viewed by others
Avoid common mistakes on your manuscript.
References
Archbold HK (1942) Physiological studies in plant nutrition. XIII Experiments with barley on defoliation and shading of ear in relation to sugar metabolism. Ann Bot 6: 487–531
Bensen AA, Bassham JA, Calvin M, Goodale TC, Haas VA and Stepka W (1950) The path of carbon in photosynthesis. V Paper chromatography and radioautography of the products. J Amer Chem Soc 72: 1710–1718
Bergmeyer HU (1970) Glutamate oxaloacetate transaminase from pig heart. In Bergmeyer HU, ed. Methods in enzymatic analysis Vol I pp 462–463, Academic Press, New York
Cochrane MP and Duffus CM (1979) Morphology and ultrastructure of immature cereal grains in relation to transport. Ann Bot 44: 67–72
Coombs J and Baldry CW (1972) The C4 pathway in Pennisetum purpureum. Nature 238: 268–270
Duffus CM and Rosie R (1973) Some enzyme activities associated with the chlorophyll containing layers of immature barley pericarp. Planta 114: 219–226
Frey-Wyssling A and Buttrose MS (1959) Photosynthesis in the ear of barley. Nature 184: 2031–2032
Hatch MD (1972) Synthesis of L-malate-4-14C and determination of label in the C-4-carboxyl of L-malate. Anal Biochem 47: 174–183
Hatch MD and Kagawa T (1974) NAD-malic enzyme in the leaves with C4 pathway: Photosynthesis and its role in C4 acid decarboxylation. Arch Biochem Biophys 160: 346–349
Hatch MD and Mau SL (1973) Activity, location and role of aspartate aminotransferase and alanine aminotransferase in leaves with C4 pathway of photosynthesis. Arch Biochem Biophys 156: 195–206
Hatch MD and Slack CR (1966) Photosynthesis by sugarcane leaves: A new carboxylation reaction and the pathway of sugar formation. Biochem J 101: 103–111
Hatch MD and Slack CR (1969) NADP specific malate dehydrogenase and glycerate kinase in leaves and evidence for their location in chloroplasts. Biochim Biophys Res commun 34: 589–593
Johnson HS and Hatch MD (1970) Properties and regulation of leaf NADP-malate dehydrogenase and malic enzyme in plants with the C4 dicarboxylic acid pathway of photosynthesis. Biochem J 119: 273–280
Kriedemann P (1966) Photosynthetic activity of the wheat ear. Ann Bot 30: 349–363
Kumar R and Singh R (1980) The relationship of starch metabolism to grain size in wheat. Photochemistry 19: 2299–2303
Kumar R, Ram H and Singh R (1982) Some of the metabolic activities of immature pericarp in developing wheat grains. Nat Acad Sci Lett (India) 5: 153–155
Latzko E, Gibbs M and Laber LJ (1971) Photosynthetic carbon metabolism in leaves of spinach and maize. In Broda E, Locker A and Springer-Lederer H, eds. First European Biophys Congress. pp 97–107, Vienna, Austria
Lowry OH, Rosebrough NJ, Farr AL and Randall RJ (1951) Protein measurement with Folin-phenol Reagent. J Biol Chem 193: 265–275
Meyer AO, Kelly GJ and Latzko E (1978) Pyruvate orthophosphate dikinase of immature wheat grains. Plant Sci Lett 12: 35–40
Meyer AO, Kelly GJ and Latzko E (1982) Pyruvate orthophosphate dikinase from the immature grains of cereal grasses. Plant Physiol 69: 7–10
Nutbeam AR and Duffus CM (1976) Evidence for C4 photosynthesis in barley pericarp tissue. Biochim Biophys Res commun 70: 1198–1203
Singal HR, Sheoran IS and Singh R (1985) Effect of water stress on photosynthesis and in vitro activities of the PCR cycle enzymes in pigeonpea (Cajanus cajan L.). Photosynthesis Research (in press)
Sinha SK, Balasubramanian V, Khanna-Chopra R and Shantakumar P (1976) Growth analysis and photosynthetic systems in relation to hybrid vigour in maize. Indian J Exp Biol 14: 459–462
Strain HH, Cope BT and Svee WA (1971) Analytical procedures for the isolation, identification, estimation and investigation of the chlorophylls. In Pietro AS, ed. Methods in Enzymology, Vol XXIII, pp 452–476, Academic Press, New York
Wirth E, Kelly GJ, Fischbeck G and Latzko E (1977) Enzyme activities and products of CO2 fixation in various photosynthetic organs of wheat and oat. Z Pflanzenphysiol 82: 78–87
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Singal, H.B., Sheoran, I.S. & Singh, R. In vitro enzyme activities and products of 14CO2 assimilation in flag leaf and ear parts of wheat (Triticum aestivum L.). Photosynth Res 8, 113–122 (1986). https://doi.org/10.1007/BF00035242
Received:
Revised:
Issue Date:
DOI: https://doi.org/10.1007/BF00035242