Coordinated nitrogen and carbon remobilization for nitrate assimilation in leaf, sheath and root and associated cytokinin signals during early regrowth of Lolium perenne

0476563 - ÚEB 2018 RIV GB eng J - Článek v odborném periodiku
Roche, J. - Turnbull, M. H. - Guo, Q. - Novák, Ondřej - Späth, J. - Gieseg, S. P. - Jameson, P. E. - Love, J.
Coordinated nitrogen and carbon remobilization for nitrate assimilation in leaf, sheath and root and associated cytokinin signals during early regrowth of Lolium perenne.
Annals of Botany. Roč. 119, č. 8 (2017), s. 1353-1364. ISSN 0305-7364. E-ISSN 1095-8290
Grant CEP: GA MŠMT(CZ) LO1204
Institucionální podpora: RVO:61389030
Klíčová slova: assimilation * cytokinin * defoliation * Lolium perenne * nitrate * Nitrogen * regrowth * water-soluble carbohydrates
Obor OECD: Plant sciences, botany
Impakt faktor: 3.646, rok: 2017

The efficiency of N assimilation in response to defoliation is a critical component of plant regrowth and forage production. The aim of this research was to test the effect of the internal C/N balance on NO- 3 assimilation and to estimate the associated cytokinin signals following defoliation of perennial ryegrass (Lolium perenne L. 'Grasslands Nui') plants. Methods Plants, manipulated to have contrasting internal N content and contrasting availability of water soluble carbohydrates (WSCs), were obtained by exposure to either continuous light or short days (8:16 h light-dark), and watered with modified N-free Hoagland medium containing either high (5 mM) or low (50lM) NO- 3 as sole N source. Half of the plants were defoliated and the root, sheath and leaf tissue were harvested at 8, 24 and 168 h after cutting. The spatiotemporal changes in WSCs, synthesis of amino acids and associated cytokinin content were recorded after cutting. Key Results Leaf regrowth following defoliation involved changes in the low- and high-molecular weight WSCs. The extent of the changes and the partitioning of theWSC following defoliation were dependant on the initialWSC levels and the C and N availability. Cytokinin levels varied in the sheath and root as early as 8 h following defoliation and preceded an overall increase in amino acids at 24 h. Subsequently, negative feedback brought the amino acid response back towards pre-defoliation levels within 168 h after cutting, a response that was under control of the C/N ratio. Conclusions WSC remobilization in the leaf is coordinated with N availability to the root, potentially via a systemic cytokinin signal, leading to efficient N assimilation in the leaf and the sheath tissues and to early leaf regrowth following defoliation.
Trvalý link: http://hdl.handle.net/11104/0273037