Download PDF
Plant Biol (Stuttg) 2005; 7(6): 601-610
DOI: 10.1055/s-2005-872881
Research Paper

Georg Thieme Verlag Stuttgart KG · New York

Contribution of Current Photosynthates to Root Respiration of Non-Nodulated Medicago sativa: Effects of Light and Nitrogen Supply

M. Lötscher1 , S. Gayler2
  • 1Plant Science Department, Technische Universität München, Am Hochanger 1, 85350 Freising-Weihenstephan, Germany
  • 2GSF - Forschungszentrum für Umwelt und Gesundheit, Institut für Bodenökologie, Ingolstädter Landstraße 1, 85764 Neuherberg, Germany
Further Information

Publication History

Received: May 9, 2005

Accepted: August 30, 2005

Publication Date:
08 November 2005 (online)

   Permissions and Reprints

Abstract

The effects of light (PFD) and nitrogen (N) supply on root respiration of new C (currently assimilated carbon, R new) and old C (R old) were analysed in non-nodulated Medicago sativa. Plants were pre-treated with high/low PFD and high/low N supply with a regular 16/8 h light/dark cycle. Five to eight weeks after planting current photosynthates were labelled with 13C and their contribution to root respiration was continuously measured during a 24 h day/night cycle. PFD conditions during labelling were either those of the pre-treatments (control, 25 or 6 mol m-2 d-1) or, for high PFD plants, 6 mol m-2 d-1 by shortening the photoperiod or reducing irradiance. The fraction of new C in the respiratory CO2 increased during the light period, but remained constant in the dark period. In control plants, R new contributed 40 % to the daily root respiration in high PFD/high N conditions. Continuously low PFD increased (50 %) and low N decreased (26 %) the contribution of R new. Exposing plants from high PFD pre-treatments to a short photoperiod or to low PFD stimulated R old, indicating mobilisation of reserve C. This stimulation was more pronounced in plants with high N supply than in those with low N supply. Comparison with other legumes suggested that R new in root respiration was mainly defined by the ratio between the assimilatory capacity of the shoots and the maintenance costs of roots with a short-term capacity of buffering respiratory demand by mobilisation of reserves in situations of fluctuating PFD.

Key words

13C labelling - current photosynthates - light - Medicago sativa - nitrogen - respiration - roots.

References

  • 1 Atkin O. K., Edwards E. J., Loveys B. R.. Response of root respiration to changes in temperature and its relevance to global warming.  New Phytologist. (2000 a);  147 141-154
    CrossrefPubMedSearch in Google Scholar
  • 2 Bingham I. J., Stevenson E. A.. Control of root growth: effects of carbohydrates on the extension, branching and rate of respiration of different fractions of wheat roots.  Physiologia Plantarum. (1993);  88 149-158
    CrossrefPubMedSearch in Google Scholar
  • 3 Bingham I. J., Panico A., Stevenson E. A.. Extension rate and respiratory activity in the growth zone of wheat roots: time-course for adjustments after defoliation.  Physiologia Plantarum. (1996);  98 201-209
    CrossrefPubMedSearch in Google Scholar
  • 4 Bouma T. J., Broekhuysen A. G. M., Veen B. W.. Analysis of root respiration of Solanum tuberosum as related to growth, ion uptake and maintenance of biomass.  Plant Physiology and Biochemistry. (1996);  34 795-806
    PubMedSearch in Google Scholar
  • 5 Bouma T. J., Nielsen K. L., Eissenstat D. M., Lynch J. P.. Estimating respiration of roots in soil: interactions with soil CO2, soil temperature and soil water content.  Plant and Soil. (1997);  195 221-232
    CrossrefPubMedSearch in Google Scholar
  • 6 Cannell M. G. R., Thornley J. H. M.. Modelling the components of plant respiration: some guiding principles.  Annals of Botany. (2000);  85 45-54
    CrossrefPubMedSearch in Google Scholar
  • 7 Dilkes N. B., Jones D. L., Farrar J.. Temporal dynamics of carbon partitioning and rhizodeposition in wheat.  Plant Physiology. (2004);  134 706-715
    CrossrefPubMedSearch in Google Scholar
  • 8 Ekblad A., Högberg P.. Natural abundance of 13C in CO2 respired from forest soils reveals speed of link between tree photosynthesis and root respiration.  Oecologia. (2001);  127 305-308
    CrossrefPubMedSearch in Google Scholar
  • 9 Farquhar G. D., Ehleringer J. R., Hubick K. T.. Carbon isotope discrimination and photosynthesis.  Annual Reviews of Plant Physiology and Molecular Biology. (1989);  40 503-537
    CrossrefPubMedSearch in Google Scholar
  • 10 Hansen G. K.. Diurnal variation of root respiration rates and nitrate uptake as influenced by nitrogen supply.  Physiologia Plantarum. (1980);  48 421-427
    PubMedSearch in Google Scholar
  • 11 Hansen A. P., Yoneyama T., Kouchi H.. Short-term nitrate effects on hydroponically-grown soybean cv. Bragg and its supernodulating mutant. I. Carbon, nitrogen and mineral element distribution, respiration and the effect of nitrate on nitrogenase activity.  Journal of Experimental Botany. (1992 a);  43 1-7
    PubMedSearch in Google Scholar
  • 12 Hansen A. P., Yoneyama T., Kouchi H.. Short-term nitrate effects on hydroponically-grown soybean cv. Bragg and its supernodulating mutant. II. Distribution and respiration of recently-fixed 13C-labelled photosynthate.  Journal of Experimental Botany. (1992 b);  43 9-14
    PubMedSearch in Google Scholar
  • 13 Hansen A. P., Yoneyama T., Kouchi H., Hiraoka K.. Respiration and nitrogen fixation of hydroponically cultured Phaseolus vulgaris L. cv. OAC Rico and a supernodulating mutant. II. Distribution and respiration of recently fixed 13C-labelled photosynthates and the effect of sink removal on carbon partitioning.  Planta. (1993 a);  189 546-556
    PubMedSearch in Google Scholar
  • 14 Hansen A. P., Yoneyama T., Kouchi H., Martin P.. Respiration and nitrogen fixation of hydroponically cultured Phaseolus vulgaris L. cv. OAC Rico and a supernodulating mutant. I. Growth, mineral composition and effect of sink removal.  Planta. (1993 b);  189 538-545
    PubMedSearch in Google Scholar
  • 15 Högberg P., Nordgren A., Buchmann N., Taylor A. F. S., Ekblad A., Högberg M. N., Nyberg G., Ottosson-Löfvenius M., Read D. J.. Large-scale forest girdling shows that current photosynthesis drives soil respiration.  Nature. (2001);  411 789-792
    PubMedSearch in Google Scholar
  • 16 Jeannette E., Rocher J. P., Prioul J. L.. Effect of an increased sink demand on the carbon metabolism and export of a maize source leaf.  Physiologia Plantarum. (1995);  94 319-327
    CrossrefPubMedSearch in Google Scholar
  • 17 Kalengamaliro N. E., Volenec J. J., Cunningham S. M., Joern B. C.. Seedling development and deposition of starch and storage proteins in alfalfa roots.  Crop Science. (1997);  37 1194-1200
    PubMedSearch in Google Scholar
  • 18 Kingston-Smith A. H., Galtier N., Pollock C. J., Foyer C. H.. Soluble acid invertase activity in leaves is independent of species differences in leaf carbohydrates, diurnal sugar profiles and paths of phloem loading.  New Phytologist. (1998);  139 283-292
    CrossrefPubMedSearch in Google Scholar
  • 19 Komor E.. Source physiology and assimilate transport: the interaction of sucrose metabolism, starch storage and phloem export in source leaves and the effects on sugar status in phloem.  Australian Journal of Plant Physiology. (2000);  27 497-505
    PubMedSearch in Google Scholar
  • 20 Kouchi H., Akao S., Yoneyama T.. Respiratory utilization of 13C-labelled photosynthates in nodulated root systems of soybean plants.  Journal of Experimental Botany. (1986);  37 985-993
    PubMedSearch in Google Scholar
  • 21 Lambers H., Scheurwater I., Atkin O. K.. Respiratory pattern in roots in relation to their functioning. Waisel, Y., Eshel, A., and Kafkafi, U., eds. Plant Roots: The Hidden Half. New York; Marcel Dekker Inc. (1996): 323-362
    Search in Google Scholar
  • 22 Le Roux X., Bariac T., Sinoquet H., Genty B., Piel C., Mariotti A., Girardin C., Richard P.. Spatial distribution of leaf water-use efficiency and carbon isotope discrimination within an isolated tree crown.  Plant, Cell and Environment. (2001);  24 1021-1032
    CrossrefPubMedSearch in Google Scholar
  • 23 Lötscher M., Klumpp K., Schnyder H.. Growth and maintenance respiration for individual plants in hierarchically structured canopies of Medicago sativa and Helianthus annuus: the contribution of current and old assimilates.  New Phytologist. (2004);  164 305-316
    CrossrefPubMedSearch in Google Scholar
  • 24 Lötscher M., Stroh K., Schnyder H.. Vertical leaf nitrogen distribution in relation to nitrogen status in grassland plants.  Annals of Botany. (2003);  92 679-688
    CrossrefPubMedSearch in Google Scholar
  • 25 Loveys B. R., Atkinson L. J., Sherlock D. J., Roberts R. L., Fitter A. H., Atkin O. K.. Thermal acclimation of leaf and root respiration: an investigation comparing inherently fast- and slow-growing plant species.  Global Change Biology. (2003);  9 895-910
    CrossrefPubMedSearch in Google Scholar
  • 26 Macduff J. H., Bakken A. K.. Diurnal variation in uptake and xylem contents of inorganic and assimilated N under continuous and interrupted N supply to Phleum pratense and Festuca pratensis.  Journal of Experimental Botany. (2003);  54 431-444
    CrossrefPubMedSearch in Google Scholar
  • 27 Merlo L., Ferretti M., Passera C., Ghisi R.. Effect of decreased irradiance on N and C metabolism in leaves and roots of maize.  Physiologia Plantarum. (1994);  91 72-80
    CrossrefPubMedSearch in Google Scholar
  • 28 Millenaar F. F., Roelofs R., Gonzalez-Meier M. A., Siedow J. N., Wagner A. M., Lambers H.. The alternative oxidase in roots of Poa annua after transfer from high-light to low-light conditions.  The Plant Journal. (2000);  23 623-632
    CrossrefPubMedSearch in Google Scholar
  • 29 Muller B., Stosser M., Tardieu F.. Spatial distribution of tissue expansion and cell division rates are related to irradiance and to sugar content in the growing zone of maize roots.  Plant, Cell and Environment. (1998);  21 149-158
    CrossrefPubMedSearch in Google Scholar
  • 30 Reuveni J., Gale J.. The effect of high levels of carbon dioxide on dark respiration and growth of plants.  Plant, Cell and Environment. (1985);  8 623-628
    PubMedSearch in Google Scholar
  • 31 Rufty  Jr. T. W., MacKown C. T., Volk R. J.. Effects of altered carbohydrate availability on whole-plant assimilation of 15NO3 -1.  Plant Physiology. (1989);  89 457-463
    PubMedSearch in Google Scholar
  • 32 Scheurwater I., Cornelissen C., Dictus F., Welschen R., Lambers H.. Why do fast- and slow-growing grass species differ so little in their rate of root respiration, considering the large differences in rate of growth and ion uptake?.  Plant, Cell and Environment. (1998);  21 995-1005
    CrossrefPubMedSearch in Google Scholar
  • 33 Schnyder H., Schäufele R., Lötscher M., Gebbing T.. Disentangling CO2 fluxes: direct measurements of mesocosm-scale natural abundance 13CO2/12CO2 gas exchange, 13C discrimination, and labelling of CO2 exchange flux components in controlled environments.  Plant, Cell and Environment. (2003);  26 1863-1874
    CrossrefPubMedSearch in Google Scholar
  • 34 Thorpe M. R., Walsh K. B., Minchin P. E. H.. Photoassimilate partitioning in nodulated soybean I. 11C methodology.  Journal of Experimental Botany. (1998);  49 1805-1815
    CrossrefPubMedSearch in Google Scholar
  • 35 Williams J. H. H., Farrar J. F.. Control of barley root respiration.  Physiologia Plantarum. (1990);  79 259-266
    CrossrefPubMedSearch in Google Scholar
  • 36 Zeeman S. C., ap Ress T.. Changes in carbohydrate metabolism and assimilate export in starch-excess mutants of Arabidopsis.  Plant, Cell and Environment. (1999);  22 1445-1453
    CrossrefPubMedSearch in Google Scholar
  • 37 Zimmerman J. K., Ehleringer J. R.. Carbon isotope ratios are correlated with irradiance levels in the Panamanian orchid Catasetum viridiflavum. .  Oecologia. (1990);  83 247-249
    CrossrefPubMedSearch in Google Scholar

M. Lötscher

Lehrstuhl für Grünlandlehre
Technische Universität München

Am Hochanger 1

85350 Freising-Weihenstephan

Germany

Email: loetscher@wzw.tum.de

Guest Editor: R. Matyssek