Soybean Plant Metabolism under Water Deficit and Xenobiotic and Antioxidant Agent Application.

Julia Renata Schneider,Mariele Müller,Geraldo Chavarria,Rômulo Pillon Barcelos,Genei Antonio Dalmago,Vilson Antonio Klein,Luciana Grazziotin Rossato-Grando

doi:10.3390/biology9090266

Julia Renata Schneider, Mariele Müller + Show 5 more

Open Access

https://doi.org/10.3390/biology9090266

Copy DOI

Abstract

The aim was to evaluate the interactive effects on biochemistry and physiology of soybean plants exposed to simultaneous xenobiotic and water deficit stresses, and the possible attenuation of plant damage by an antioxidant agent. Soybean plants were submitted to eight different soil water potentials, in two experiments (first experiment: −0.96, −0.38, −0.07, −0.02 MPa, and second experiment: −3.09, −1.38, −0.69, −0.14 MPa), xenobiotic, and antioxidant agent applications. Was observed a reduction in water status, gas exchange, photosynthetic pigments, photosystem II quantum yield, and increased leaf temperature in plants under low water availability. Water deficit also induced oxidative stress by the increased production of reactive oxygen species, cellular and molecular damage, and induction of the antioxidant defense metabolism, reduction of gas exchange, water status, and photosynthetic efficiency. The xenobiotic application also caused changes, with deleterious effects more pronounced in low soil water availability, mainly the reactive oxygen species production, consequently the antioxidant activity, and the oxidative damages. This indicates different responses to the combination of stresses. Antioxidant enzyme activity was reduced by the application of the antioxidant agent. Principal Component Analysis showed a relation with the antioxidant agent and reactive oxygen species, which is probably due to signaling function, and with defense antioxidant system, mainly glutathione, represented by thiols.

Highlights

Plants are constantly exposed to environmental stresses responsible for physiological changes and oxidative stress
These were maintained in a growth chamber under conditions of 14 h of light, 25 ± 2 ◦ C of temperature, and 300 μmol m−2 s−1 of photon flux density
Leaf water potential presented a response with quadratic behavior, and 99% of the variation

Summary

Introduction

Plants are constantly exposed to environmental stresses responsible for physiological changes and oxidative stress. Even under water deficit conditions, it is necessary to apply a fungicide It occurs because most growers have been using the application time following one predetermined calendar schedule, according to the critical development stage of the plant, the first application, or even the Biology 2020, 9, 266; doi:10.3390/biology9090266 www.mdpi.com/journal/biology. Biology 2020, 9, 266 residual period of the products [5] This can lead plants to combined stress factors if the fungicide is a xenobiotic, which causes alterations in plant metabolism [6]. A large amount of research has shown plant responses to isolated stresses, which is incompatible with the reality of field conditions [7], but recent studies have confirmed that plants are exposed to a combination of stresses [7,8], demanding findings in this sense. Plant performance in a water-restricted environment is already consolidated, still needs to elucidate plant to multiple stresses [9,10], such as water deficit stress and fungicide application

Objectives

Methods

Results

Discussion

Conclusion