Effet de la coupe des parties aériennes et du déficit hydrique sur la dynamique racinaire, la biologie et l'histologie des nodosités du trèfle blanc (Trifolium Repens L.)

Abstract : Experiments conducted under controlled conditions on white clover allowed to study the effect of plant defoliation and water stress on the root growth, the morphological and histological aspects of the nodules, and the nitrogen fixation activity. Results of there experimentas showed that : - Under controlled condition, the nodules were still alive after a period of 5 months. – The plant defoliation determined a decrease of the root growth. This treatment affected also the histological and Ultrastructural studies showed that the bacteroids were changed in their form and structure. The change was visible 1 day after plant defoliation. The polysaccharide contents were influenced by these treatment. 7 days after defoliation, the nodule activity is restored according to the formation of the new infected cells by the meristem. – The water stress (water withholding or addition of the osmoticum “PEG”) induced a decreasing of root growth. The potassium supply allowed a better water balance of the root nodules and an increase in nodule biomass. The water deficit determined : - an accumulation of polysaccharide in the bacteroid region and the degeneration of the bacteroid itself. – A digitation of the cell wall in the infected cells. However, after rehydration, the proportions of the different regions of the nodule are similar to those of the control plants. The senescence region seems to be less disorganized than during the stress period. The polysaccharides were again well distributed to all nodule cells. The rehydration promoted the root growth and the formation of new nodules. The results were discussed with the objective to obtain a better knowledge about the underground part of the white clover plant
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http://docnum.univ-lorraine.fr/prive/INPL_T_1991_MULJANTO_D.pdf
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Submitted on : Thursday, March 29, 2018 - 1:33:30 PM
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Djoko Muljanto. Effet de la coupe des parties aériennes et du déficit hydrique sur la dynamique racinaire, la biologie et l'histologie des nodosités du trèfle blanc (Trifolium Repens L.). Autre. Institut National Polytechnique de Lorraine, 1991. Français. ⟨NNT : 1991INPL029N⟩. ⟨tel-01752161⟩

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