Abstract
Barley (Hordeum vulgare L.) leaves and intact spinach (Spinacia oleracea L.) chloroplasts were exposed to short-term heating, and the aftereffects of heat treatment on in vitro andin vivo activities of nitrate reductase and noncyclic electron transport associated with nitrite reduction were studied. Heating of leaves at temperatures above 40°C led to a monotonic decrease in nitrate reductase in vitro activity. On the contrary, the in vivo enzyme activity, assayed in intact leaf tissues after 5-min heat treatment, increased 1.5 times upon elevating the pretreatment temperature from 37 to 40°C and gradually decreased at higher temperatures. Noncyclic electron transport related to CO2 fixation in intact chloroplasts decreased gradually after heat exposures above 39°C, unlike the electron transport to nitrite as a terminal acceptor, which was stimulated by heating of intact chloroplast suspensions in the temperature range from 33 to 40°C. The heating at higher temperatures inhibited nitrite photoreduction. It is concluded that the heating of phototrophic cells at sublethal temperatures stimulates the mobilization of inorganic nitrogen and thereby facilitates the repair of thermally induced injuries of proteinaceous cell structures. The stimulation of nitrate reductase activity in vivo at the temperature range 37–40°C provides an evidence for the increase in the availability of reductants in the cytosolic compartment of the leaf cell.
Similar content being viewed by others
REFERENCES
Weis, E., Reversible Heat-Inactivation of the Calvin Cycle: A Possible Mechanism of the Temperature Regulation of Photosynthesis, Planta, 1981, vol. 151, pp. 33–39.
Yamashita, T. and Butler, W.L., Inhibition of Chloroplasts by UV-Irradiation and Heat-Treatment, Plant Physiol., 1968, vol. 43, pp. 2037–2040.
Bukhov, N.G., Samson, G., and Carpentier, R., Nonphotosynthetic Reduction of the Intersystem Electron Transport Chain of Chloroplasts Following Heat Stress. Steady-State Rate, Photochem. Photobiol., 2000, vol. 72, pp. 351–357.
Havaux, M., Short-Term Responses of PSI to Heat Stress. Induction of a PSII-Independed Electron Transport through PSI Fed by Stromal Components, Photosynth. Res., 1996, vol. 47, pp. 85–97.
Egorova, E.A. and Bukhov, N.G., Effect of Elevated Temperatures on the Activity of Alternative Pathways of Photosynthetic Electron Transport in Intact Barley and Maize Leaves, Fiziol. Rast. (Moscow), 2002, vol. 49, pp. 645–654 (Russ. J. Plant Physiol., Engl. Transl.).
Egorova, E.A., Bukhov, N.G., Heber, U., Samson, G., and Carpentier, R., Effect of the Pool Size of Stromal Reductants on the Alternative Pathway of Electron Transfer to Photosystem I in Chloroplasts of Intact Leaves, Fiziol. Rast. (Moscow), 2003, vol. 50, pp. 485–495 (Russ. J. Plant Physiol., Engl. Transl.).
Solomonson, L.P. and Barber, M.J., Assimilatory Nitrate Reductase: Functional Properties and Regulation, Annu. Rev. Plant Physiol. Plant Mol. Biol., 1990, vol. 41, pp. 225–253.
Lillo, C., Light Regulation of Nitrate Reductase in Green Leaves of Higher Plants, Physiol. Plant., 1994, vol. 90, pp. 616–620.
Heber, U., Bukhov, N.G., Neimanis, S., and Kobayashi, Y., Maximum H+/h? PSI Stoichiometry of Proton Transport during Cyclic Electron Flow in Intact Chloroplasts Is at Least Two, but Probably Higher than Two, Plant Cell Physiol., 1995, vol. 36, pp. 1639–1647.
Kaiser, W.M., Kandlbinder, A., Stoimenova, M., and Glaab, J., Discrepancy between Nitrate Reduction Rates in Intact Leaves and Nitrate Reductase Activity in Leaf Extracts: What Limits Nitrate Reduction In Situ? Planta, 2000, vol. 210, pp. 801–807.
Jensen, R.G. and Bassham, J.A., Photosynthesis by Isolated Chloroplasts, Proc. Natl. Acad. Sci. USA, 1966, vol. 56, pp. 1095–1101.
Hageman, R.H. and Hucklesby, D.P., Nitrate Reductase from Higher Plants, Methods Enzymol., 1971, vol. 23, pp. 491–503.
Scholl, R.L., Harper, J.E., and Hageman, R.H., Improvement of the Nitrite Color Development in Assays of Nitrate Reductase by Phenasine Methosulfate and Zinc Acetate, Plant Physiol., 1974, vol. 53, pp. 825–828.
Klepper, L., Flesher, D., and Hageman, R.H., Generation of Reduced Nicotinamidadenine Dinucleotide for Nitrate Reduction in Green Leaves, Plant Physiol., 1971, vol. 48, pp. 580–590.
Naik, M.S., Abrol, Y.P., Nair, T.V.R., and Ramarao, C.S., Nitrate Assimilation-Its Regulation and Relationship to Reduced Nitrogen in Higher Plants, Phytochemistry, 1982, vol. 21, pp. 495–504.
Gounaris, K., Brain, A.R.R., Quinn, P.J., and Williams, W.P., Structural Reorganization of Chloroplast Thylakoid Membranes in Response to Heat Stress, Biochim. Biophys. Acta, 1984, vol. 766, pp. 198–208.
Kobayashi, Y., Neimanis, S., and Heber, U., Coupling Ratios H+/e = 3 versus H+/e = 2 in Chloroplasts and Quantum Requirements of Net Oxygen Exchange during the Reduction of Nitrite, Ferricyanide and Methylviologen, Plant Cell Physiol., 1995, vol. 36, pp. 1613–1620.
Krause, G.H. and Weis, E., Chlorophyll Fluorescence and Photosynthesis: The Basics, Annu. Rev. Plant Physiol. Plant Mol. Biol., 1991, vol. 42, pp. 313–349.
Heber, U. and Walker, D., Concerning a Dual Function of Coupled Cyclic Electron Transport in Leaves, Plant Physiol., 1992, vol. 100, pp. 1621–1626.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Maevskaya, S.N., Egorova, E.A. & Bukhov, N.G. Effect of Elevated Temperature on Nitrite and Nitrate Reduction in Leaves and Intact Chloroplasts. Russian Journal of Plant Physiology 50, 599–603 (2003). https://doi.org/10.1023/A:1025675721136
Issue Date:
DOI: https://doi.org/10.1023/A:1025675721136