Abstract

FAGGIOLI, Valeria S.; MARTA, Cabello; MARIANA, Melchiorre N  and  FERNANDA, Covacevich. Contribution of indigenous arbuscular mycorrhizal fungi to phosphorus nutrition and its effect on photoassimilates partitioning of soybean. Cienc. suelo [online]. 2020, vol.38, n.1, pp.81-94. ISSN 1850-2067.

Association strategies between plants and arbuscular mycorrhizal fungi (AMF) could be used to ensure an efficient phosphorus (P) nutrition. However, it is unknown if current long-term practices of soybean crop production depressed potential for indigenous AMF colonization and growth promotion. Our objective was to assess the contribution on growth, P uptake and photo-assimilate partitioning in soybean. A greenhouse trial (60 days) was installed with 4 treatments (with "+" and without "-" AMF indigenous from a long-term soybean crop from Cordoba; with "+" and without "-" P fertilization by weekly application of 15.5 mg P pot^-1). Indigenous AMF colonized soybean roots and favored plants growth even when the P supply was not limiting. The intra and extra-radical presence of AMF as well as the supply of P, favored the growth, the accumulation of P and the content and the partition of sugars in the soybean plants. Plants that grew in the presence of mycorrhizae (+AMF) without P supply (-P) showed increases in dry matter and accumulated P. Although there was no significant increase in the P uptake by mycorrhizae, plants in the +AMF and +P condition showed a positive response to mycorrhizal colonization in their aerial growth. Plants that grew in the -AMF and +P condition did not show higher growth. This highlights the importance of management practices for soybean crop that, in combination with moderate P fertilization aimed for nutrient replenishment; favor the maintenance of indigenous AMF activities.

Keywords : Mycorrhizal symbiosis; carbohydrates; colonization; phosphorus.

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