SYMBIOTIC EFFICIENCY OF INOCULATION WITH NITROGEN-FIXING BACTERIA AND ARBUSCULAR MYCORRHIZAL FUNGI IN Tachigali vulgaris SEEDLINGS

Juliana Müller Freire,Jerri Edson Zilli,Janaína Ribeiro Costa Rouws,Isabel Silveira Camargo,Ederson Da Conceição Jesus,Orivaldo José Saggin Júnior,Sérgio Miana De Faria

doi:10.1590/1806-908820200000024

Juliana Müller Freire, Jerri Edson Zilli + Show 5 more

Open Access

https://doi.org/10.1590/1806-908820200000024

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Abstract

ABSTRACT The present study aimed to evaluate the effect of inoculation with nitrogen-fixing bacteria (NFB) and arbuscular mycorrhizal fungi (AMF) on the development of Tachigali vulgaris seedlings under nursery conditions. The seedlings were produced in 1 kg bags on a substrate of sand and vermiculite (1:1), following a completely randomized experimental design in a 3 (NFB) x 2 (with and without AMF) factorial scheme with 3 additional control treatments consisting of: seedlings inoculated only with AMF (mycorrhizal control), non-inoculated seedlings fertilized with N (nitrogenized control) and without N (absolute control). The following variables were evaluated: height, stem diameter (SD), shoot dry mass (SDM), root dry mass (RDM) and nodule dry mass (NDM), P accumulation in the shoot, and root mycorrhizal colonization (RMC). Efficiency and effectiveness were calculated to evaluate the plant response to double inoculation. The treatments showed a significant effect for all variables, except for mycorrhizal colonization, nodule number, and dry mass, with the nitrogen treatment having the highest growth values. Plants submitted to double inoculation showed a higher accumulation of dry matter, height and SD, reaching a 124% higher RDM regarding the absolute control, 90% more SDM, and 207% more NDM regarding the seedlings inoculated only with rhizobia. The positive effect of double inoculation occurred regardless of the strain used. The results indicate that the joint inoculation of NFB and AMF was beneficial for the species, promoting its growth.

Highlights

Several forest planting methodologies have been adopted to recover degraded areas, among which the use of nitrogenfixing bacteria (NFB) and arbuscular mycorrhizal fungi (AMF) in mutualistic symbiosis with legumes is highlighted (Chaer et al, 2011)
The present study aimed to evaluate the effect of inoculation with nitrogen-fixing bacteria (NFB) and arbuscular mycorrhizal fungi (AMF) on the development of Tachigali vulgaris seedlings under nursery conditions
Plants submitted to double inoculation showed a higher accumulation of dry matter, height and stem diameter (SD), reaching a 124% higher root dry mass (RDM) regarding the absolute control, 90% more shoot dry mass (SDM), and 207% more nodule dry mass (NDM) regarding the seedlings inoculated only with rhizobia

Summary

Introduction

Several forest planting methodologies have been adopted to recover degraded areas, among which the use of nitrogenfixing bacteria (NFB) and arbuscular mycorrhizal fungi (AMF) in mutualistic symbiosis with legumes is highlighted (Chaer et al, 2011). NFB can supply a plant with 60 to 100% of its nitrogen needs when in symbiosis, which can reach up to 600 kg of N ha-1 per year (Peoples et al, 2009; Döbereiner, 1984) Such an association offers economic and ecological advantages when dispensing with the use of nitrogen fertilizers, which imply in large consumption of fossil fuels to reach the necessary temperatures and pressure in order to be industrially produced by the Haber-Bosch process (Travis, 2017). This constitutes a relevant factor in the tropics where low fertility soils predominate (Smith and Smith, 2011)

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