Nitrogen source influences the antioxidative system of soybean plants under hypoxia and re-oxygenation

Abstract

In this work, we compared nitrate-supplied plants (non-nodulated) with non-nitratesupplied plants (nodulated) under oxygen privation of root system (hypoxia) and re-oxygenation (post-hypoxia; recovery) in order to verify whether N sources affect the antioxidant system during oxidative stress caused by hypoxia and post-hypoxia conditions. Antioxidant enzymatic activities, ascorbate redox state, and reactive oxygen species (ROS) levels were analyzed in roots and leaves of two soybean genotypes, Fundacep 53 RR and BRS Macota at reproductive stage R2, during hypoxia and post-hypoxia in an experiment carried out in a hydroponic system. The antioxidant system was strongly induced in roots of nitrate-supplied plants of both genotypes, with high activity of superoxide dismutase, ascorbate peroxidase, catalase, glutathione reductase and guayacol peroxidase. It also increased reduced ascorbate and ascorbate redox state and decreased ROS production under hypoxia and recovery, while in leaves of nodulated and non-nodulated plants, a slight increase on antioxidant system was observed. Nitrate may benefit soybean plants under hypoxic conditions and subsequent re-oxygenation by inducing the antioxidant system mainly in roots to cope with ROS production and reduce oxidative damage.

Nitrogen Enhances Salt Tolerance by Modulating the Antioxidant Defense System and Osmoregulation Substance Content in Gossypium hirsutum

“…The elimination of H 2 O 2 might be due to the immediate strengthening of SOD, CAT, and POD activities (Figure 8), and the increased content of free amino acids (Figure 5E,F) by higher nitrogen application. Moreover, in support of the outcomes of the present study, several other scholars reported that co-application of nitrogen significantly boosted the level of antioxidant enzymes in soybean [56], Catharanthus roseus [57], and blueberry [58]. Nitrogen serves as a first line of defense against internal and environmental oxidative stressors [17,21,59,60].…”

Mechanisms of Waterlogging Tolerance in Plants: Research Progress and Prospects

“…Pyruvate accumulated from glycolysis can be used for anaerobic fermentation. Pyruvate fermentation produces energy in two different ways, producing lactic acid either via lactate dehydrogenase (LDH) or via pyruvate decarboxylase (PDC) turning pyruvate into acetaldehyde, which is then reduced to ethanol by alcohol dehydrogenase (ADH) ( Zabalza et al, 2009 ; Caruso et al, 2012 ; Borella et al, 2019 ). ADH and PDC play key roles in the ethanol fermentation pathway, and their activity is usually considered as one of the important indexes reflecting the tolerance of plants to waterlogging.…”

Use of inoculants and nitrogen fertilization related to yield and quality of soybean grains

“…Zuffo et al (2018a) estuda diferença fisiológica entre cultivares num solo com boa fertilidade inicial e debatem que a diferença na qualidade fisiológica dos materiais, se dá a característica genética da cultivar de soja, relacionando se pouco com a aplicação de N, uma vez que o que será consumido pela cultura será através da FBN. Oliveira et al (2019), busca em seu trabalho através da fertilização nitrogenada foliar resultados sobre a produção, uma vez que este é o índice mais importante, no entanto, mesmo na aplicação foliar não há significância no acréscimo de produção. Reafirmando o resultado deste trabalho, que, a inoculação torna a FBN eficaz, e simbiose plantarizóbio agrega o macronutriente N em quantidade suficiente para o bom desenvolvimento da cultura.…”

“…O tratamento com N, porém, em outras circunstancias pode trazer resultado benéfico significativo, como cita Borella et al (2019), que estuda aplicação de N em condições de hipóxia para cultura da soja. Bahry et al (2014), avaliando a soja em estresse hídrico cita que a aplicação N principalmente no período de florada pode resultar em maior número de grãos por vagem e maior massa de mil grãos no seu trabalho.…”