Contribution à l'étude de l'allocation des photoassimilats récents dans la plante et la rhizosphère chez une graminée pérenne (Lolium perenne L.)

Abstract : The aim of our work was to study C fluxes in plant and to rhizosphere of Lolium perenne inorder to explain the relation between plant functioning and rhizodeposition. In a first part, we have determined the contribution of recently assimilated carbon to rhizodeposition. We have developed a double long-term labelling of plants shoots (14CO2 and 13COV in order to estimate partitioning of recent C and older assimilated C in plant andrhizosphere compartment. ln contrast to previous results, older C, probably coming fromremobilisation of reserve compounds, contribute significantly to rhizodeposition.ln a second part, we have evaluated, with field trials, the influence of constraint affecting plants shoots on recently assimilated C fluxes to rhizosphere (elevated CO2, defoliation). Soil nitrogen availability is the driving force of plants responses to elevated CO2 or defoliation. ln autumn, a decrease of C rhizodeposition is observed for plants submitted to elevated CO2 Organics compounds released by roots are mineralised faster under elevated CO2 than underambient CO2. Defoliation involved any change in C availability in the rhizosphere, suggesting any significant influence ofthis factor on rhizodeposition. Interactions between environmental and management factors determined plantfunctioning and modulated C fluxes from roots which give rhizodeposition difficult to predict and to model. Net effect of elevated CO2 or defoliation on rhizodeposition are less significant under field conditions than under controlled conditions. More than quantitative contribution ofrhizodeposition to soil C pool, interactions between biochemical composition of rhizodeposits and soil biological activity need to be complete.
Document type :
Theses
Complete list of metadatas

https://hal.univ-lorraine.fr/tel-01749951
Contributor : Thèses Ul <>
Submitted on : Thursday, March 29, 2018 - 12:34:09 PM
Last modification on : Tuesday, April 10, 2018 - 1:28:03 AM
Long-term archiving on : Friday, September 14, 2018 - 10:55:55 AM

File

INPL_T_2005_BAZOT_S.pdf
Files produced by the author(s)

Identifiers

  • HAL Id : tel-01749951, version 1

Collections

Citation

Stéphane Bazot. Contribution à l'étude de l'allocation des photoassimilats récents dans la plante et la rhizosphère chez une graminée pérenne (Lolium perenne L.). Sciences agricoles. Institut National Polytechnique de Lorraine, 2005. Français. ⟨NNT : 2005INPL043N⟩. ⟨tel-01749951⟩

Share

Metrics

Record views

18

Files downloads

19