Publications des scientifiques de l'IRD

Ranoarisoa M. P., Morel C., Andriamananjara A., Jourdan C., Bernard Laetitia, Becquer Thierry, Rabeharisoa L., Rahajaharilaza K., Plassard C., Blanchart Eric, Trap Jean. (2018). Effects of a bacterivorous nematode on rice P-32 uptake and root architecture in a high P-sorbing ferrallitic soil. Soil Biology and Biochemistry, 122, p. 39-49. ISSN 0038-0717.

Titre du document
Effects of a bacterivorous nematode on rice P-32 uptake and root architecture in a high P-sorbing ferrallitic soil
Année de publication
2018
Type de document
Article référencé dans le Web of Science WOS:000435053800005
Auteurs
Ranoarisoa M. P., Morel C., Andriamananjara A., Jourdan C., Bernard Laetitia, Becquer Thierry, Rabeharisoa L., Rahajaharilaza K., Plassard C., Blanchart Eric, Trap Jean
Source
Soil Biology and Biochemistry, 2018, 122, p. 39-49 ISSN 0038-0717
Soil bacterivorous nematodes are key plant mutualists that increase nutrient availability for plants either by enhancing the mineralization of organic compounds (the "mineralization pathway") or by increasing plant lateral root branching following shifts in internal plant metabolism, and subsequently leading to a higher volume of soil prospected by the roots (the "hormonal pathway"). The effects of these organisms on the nutrition of plants growing in strongly nutrient-deficient ferrallitic soils, especially in soils with limited available inorganic phosphorus (P), are poorly known, as are the pathways involved. In our study, using Oryza saliva (Poaceae) and Acrobeloides sp. (Cephalobidae), we tested the "mineralization" and "hormonal" hypotheses in an acidic P-depleted Ferralsol from the Madagascar highlands. We assessed the effect of nematode inoculation on (i) inorganic P flow from soil to plant using the P-32 labelling technique and (ii) plant root architecture using a rhizobox device. We showed that the ability of Acrobeloides sp. to enhance P uptake in plants is strongly limited in Ferralsols. However, when the soil pH was corrected with dolomite, Acrobeloides sp. increased plant P uptake probably through the "mineralization" pathway (higher microbial turnover). Indeed, the L-value increased by 49% in the presence of nematodes and dolomite, suggesting the production of unlabelled plant-available P, probably through a higher net P mineralization when the nematodes were inoculated. Using the rhizobox technique, we also observed increased root length in the presence of nematodes but the specific root length, the tip number and the root branching density did not increase in the presence of nematodes, suggesting that nematodes did not increase plant P uptake and growth in this soil as proposed by the "hormonal" hypothesis. From an ecological intensification perspective, to promote agro-ecological development in tropical regions, our results suggest that amending ferrallitic soils with P-rich organic matter and correcting soil pH with an appropriate amount of dolomite may constitute suitable agronomic actionable triggers to drive the mutualistic activity of bacterivorous nematodes.
Plan de classement
Pédologie [068] ; Biologie du sol [074] ; Sciences du monde végétal [076]
Description Géographique
MADAGASCAR ; ZONE TROPICALE
Localisation
Fonds IRD [F B010073163]
Identifiant IRD
fdi:010073163
Contact