Cytokinin-induced changes of nitrogen remobilization and chloroplast ultrastructure in wheat (Triticum aestivum)
| Autor: | Atilio J. Barneix, Irma N. Roberts, Carla Caputo, Maria Victoria Criado, María A. Castro |
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| Rok vydání: | 2009 |
| Předmět: |
Chloroplasts
Cytokinins Nitrogen Physiology NITROGEN STARVATION Plant Science Protein degradation TRITICUM AESTIVUM Nitrate reductase Polymerase Chain Reaction chemistry.chemical_compound BENZYLAMINOPURINE Botany Sugar Triticum DNA Primers Base Sequence biology Agricultura fungi RuBisCO CHLOROPLAST food and beverages NITROGEN REMOBILIZATION Chloroplast Microscopy Electron chemistry CIENCIAS AGRÍCOLAS Chlorophyll Cytokinin biology.protein Phloem Agricultura Silvicultura y Pesca Agronomy and Crop Science |
| Zdroj: | Journal of Plant Physiology. 166:1775-1785 |
| ISSN: | 0176-1617 |
| DOI: | 10.1016/j.jplph.2009.05.007 |
| Popis: | Nitrogen (N) remobilization in wheat (Triticum aestivum) plants is crucial because it determines the grain protein concentration and the baking quality of flour. In order to evaluate the influence of cytokinins on N remobilization during N starvation, we analyzed various N remobilization parameters in wheat plants that were watered with 6-benzylaminopurine (BAP) either with or without KNO3. Besides, the effects of BAP on protein synthesis were evaluated, and the size and ultrastructure of chloroplasts of BAP-treated plants were studied. BAP supply inhibited N remobilization of plants independently of N supply as shown by the increase in protein, Rubisco, chlorophyll, sugar and starch concentrations in the older leaves, the decrease in amino acid and sugar export to the phloem, and the decrease in protein, Rubisco and chlorophyll concentrations in the younger leaves. Besides, BAP supply increased nitrate reductase activity and decreased nitrate concentration, thus suggesting an increased assimilatory capacity. The increase in protein concentration could be explained mainly by a significant decrease in protein degradation and, to a lesser extent, by an increase in protein synthesis. Finally, an increase both in the size of the chloroplast and in the plastoglobuli and starch contents in BAP-supplied plants was observed. We propose that cytokinins retain the sink activity of the older leaves by inhibiting amino acid and sugar export to the phloem and stimulating assimilate accumulation in the chloroplasts of the older leaves. Besides, BAP may increase protein concentration of the older leaves both by decreasing protein degradation and maintaining protein synthesis even under stress conditions. © 2009 Elsevier GmbH. All rights reserved. Fil: Criado, Maria Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Invetigaciones Bioquímicas y Fisiologicas; Argentina Fil: Caputo Suarez, Carla Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Invetigaciones Bioquímicas y Fisiologicas; Argentina Fil: Roberts, Irma. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Invetigaciones Bioquímicas y Fisiologicas; Argentina Fil: Castro, Maria A.. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental; Argentina Fil: Barneix, Atilio José. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Invetigaciones Bioquímicas y Fisiologicas; Argentina |
| Databáze: | OpenAIRE |
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