Abstract
Illumination of leaves of C3 plants caused cytosolic alkalization and vacuolar acidification in the mesophyll cells. Both phenomena were particularly pronounced when CO2 was absent, were suppressed by CO2, and were related to the activation state of the photosynthetic apparatus. The cytosolic alkalization reaction has at least two major components. Trivalent cytosolic phosphoglycerate must be protonated before it can be transferred into the chloroplasts for reduction. Pumping of protons from the cytosol into the vacuole also contributes to cytosolic alkalization. The dependence of light scattering by chloroplast thylakoids on the energy fluence rate was closely related to that of vacuolar acidification under different conditions for chloroplast energization. This indicates (i) transport of energy from the chloroplasts to the cytosol in the light and (ii) use of this energy for the transport of protons into the vacuoles. The light-dependent vacuolar acidification is interpreted to be caused by the increase in the activity of a proton-translocating enzyme of the tonoplast. The decrease of vacuolar acidification during photosynthetic carbon reduction or photorespiration is indicative of decreased cytosolic energization. In low light, the light-dependent vacuolar acidification was stimulated in the absence of CO2 when photorespiration was inhibited. The data do not support the view that photorespiration is capable of increasing the cytosolic energy state in the light.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Bilger, W., Heber, U., Schreiber, U. (1988) Kinetic relationships between energy-dependent fluorescence quenching, light scattering, chlorophyll luminescence and proton pumping in intact leaves. Z. Naturforsch. 43c, 877–887
Fiolet, J.W., Bakker, E.P., van Dam, K. (1974) The fluorescent properties of acridines in the presence of chloroplasts or liposomes. Biochim. Biophys. Acta 368, 432–445
Gardeström, P. (1987) Adenylate ratios in the cytosol, chloroplasts and mitochondria of barley protoplasts during photosynthesis at different carbon dioxide concentrations. FEBS Lett. 212, 114–118
Heber, U. (1969) Conformational changes of chloroplasts induced by illumination of leaves in vivo. Biochim. Biophys. Acta 180, 302–319
Heber, U., Heldt, H.W. (1981) The chloroplast envelope: structure, function and role in leaf metabolism. Annu. Rev. Plant Physiol. 32, 139–168
Heber, U., Krause, G.H. (1971) Transfer of carbon, phosphate energy and reducing equivalents across the chloroplast envelope. In: Photosynthesis and photorespiration, pp. 218–225, Hatch, M.D., Osmond, C.B., Slatyer, R.O., eds. Wiley, New York
Heber, U., Santarius, K.A. (1970) Direct and indirect transport of ATP and ADP across the chloroplast envelope. Z. Naturforsch. 25b, 718–728
Heber, U., Schreiber, U., Siebke, K., Dietz, K.-J. (1990) Relationship between light-driven electron transport, carbon reduction and carbon oxidation in photosynthesis. In: Perspectives in biochemical and genetic regulation of photosynthesis, pp. 1–37, Zelitch, I., ed. Liss, New York
Heldt, H.W., Werdan, K., Milovancev, M., Geller, G. (1973) Alkalization of the chloroplast stroma caused by light-dependent proton flux into the thylakoid space. Biochim. Biophys. Acta 314, 224–241
Kobayashi, Y., Köster, S., Heber, U. (1982) Light scattering, chlorophyll fluorescence and state of the adenylate system in illuminated spinach leaves. Biochim. Biophys. Acta 682, 44–54
Köster, S., Heber, U. (1982) Light scattering and quenching of 9-aminoacridine fluorescence as indicators of the phosphorylation state of the adenylate system in intact spinach chloroplasts. Biochim. Biophys. Acta 680, 88–94
Laisk, A., Oja, V., Kiirats, O., Raschke, K., Heber, U. (1989) The state of the photosynthetic apparatus in leaves as analyzed by rapid gas exchange and optical methods: The pH of the chloroplast stroma, and activation of enzymes in vivo. Planta 177, 350–358
Oja, V., Laisk, A., Heber, U. (1986) Light-induced alkalization of the chloroplast stroma as estimated from the CO2 capacity of intact sunflower leaves. Biochim. Biophys. Acta 849, 355–365
Pfanz, H., Heber, U. (1986) Buffer capacities of leaves, leaf cells and leaf cell organelles in relation to fluxes of potentially acidic gases. Planta Physiol. 81, 597–602
Stitt, M., Lilley, R.McC., Heldt, H.W. (1982) Adenine nucleotide levels in the cytosol, chloroplasts and mitochondria of wheat leaf protoplasts. Plant Physiol. 70, 971–977
Sze, H. (1985) H2+-translocating ATPases. Advances using membrane vesicles. Annu. Rev. Plant Physiol. 36, 175–208
Wagner, U., Oja, V., Laisk, A., Heber, U. (1990) pH homeostasis of the chloroplast stroma can protect photosynthesis of leaves during the influx of potentially acidic gases. Biochim. Biophys. Acta, 1016, 115–120
Yin, Z.-H., Neimanis, S., Wagner, U., Heber, U. (1990) Light-dependent pH changes in leaves of C3 plants. I. Recording pH changes in various cellular compartments by fluorescence probes. Planta 182, 244–252
Yokota, A., Kitaoka, S. (1985) Correct pK values for dissociation constant of carbonic acid lower the reported Km values of ribulose bisphosphate carboxylase to half. Presentation of a nonograph and an equation for determining the pK values. Biochem. Biophys. Res. Commun. 131, 1075–1079
Author information
Authors and Affiliations
Additional information
This work was supported by the Sonderforschungsbereiche 176 and 251 of the University of Würzburg. Z.-H. Y. acknowledges support by the Leibniz program of the Deutsche Forschungsgemeinschaft and by the Committee for Education of the People's Republic of China.
Rights and permissions
About this article
Cite this article
Yin, ZH., Neimanis, S. & Heber, U. Light-dependent pH changes in leaves of C3 plants. Planta 182, 253–261 (1990). https://doi.org/10.1007/BF00197119
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00197119