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Modulation of nitrogen metabolism of maize plants inoculated with Azospirillum brasilense and Herbaspirillum seropedicae

da Fonseca Breda, Farley Alexandre, da Silva, Thamires Ferreira Rodrigues, dos Santos, Silvana Gomes, Alves, Gabriela Cavalcanti, Reis, Veronica Massena
Archives of microbiology 2019 v.201 no.4 pp. 547-558
Azospirillum brasilense, Herbaspirillum seropedicae, ammonium, corn, enzyme activity, fertilizer application, hydroponics, leaves, nitrate reductase, nitrates, nitrogen, nitrogen content, nitrogen fertilizers, nitrogen metabolism, nitrogen-fixing bacteria, phosphorus, plant growth, potassium, roots, shoots, sugars
Maize is highly responsive to the application of nitrogen to achieve high productivity. Inoculation with diazotrophic bacteria can improve plant growth with low N fertilization. The objective was to evaluate the inoculation of two species of diazotrophs on N metabolism in maize plants, in the presence of two concentrations of nitrogen in a hydroponic system. A factorial arrangement composed of two N levels (3.0 and 0.3 mM), with the presence of Hs—Herbaspirillum seropedicae, and Ab—Azospirillum brasilense or not. The parameters used were dry mass; N, P, and K accumulation; nitrate reductase activity; soluble fractions in roots and leaves. The inoculation altered the N metabolism and promoted greater development of maize plants, as well as a higher accumulation of P and K in the shoots. A more intensive process of N assimilation was evidenced when the plants were inoculated with H. seropedicae, leading to increased levels of NO₃⁻ and reduced N-amino, sugars, and NH₄⁺ in leaves associated with high N level, opposite of A. brasilense.