Reactive oxygen species and antioxidant machinery in abiotic stress tolerance in crop plants

The contamination of soils and water with metals has created a major environmental problem, leading to considerable losses in plant productivity and hazardous health effects. Exposure to toxic metals can intensify the production of reactive oxygen species (ROS), which are continuously produced in both unstressed and stressed plants cells. Some of the ROS species are highly toxic and must be detoxified by cellular stress responses, if the plant is to survive and grow. The aim of this review is to assess the mode of action and role of antioxidants in protecting plants from stress caused by the presence of heavy metals in the environment.

Making the life of heavy metal-stressed plants a little easier

Global climate change and associated adverse abiotic stress conditions, such as drought, salinity, heavy metals, waterlogging, extreme temperatures, oxygen deprivation, etc., greatly influence plant growth and development, ultimately affecting crop yield and quality, as well as agricultural sustainability in general. Plant cells produce oxygen radicals and their derivatives, so-called reactive oxygen species (ROS), during various processes associated with abiotic stress. Moreover, the generation of ROS is a fundamental process in higher plants and employs to transmit cellular signaling information in response to the changing environmental conditions. One of the most crucial consequences of abiotic stress is the disturbance of the equilibrium between the generation of ROS and antioxidant defense systems triggering the excessive accumulation of ROS and inducing oxidative stress in plants. Notably, the equilibrium between the detoxification and generation of ROS is maintained by both enzymatic and nonenzymatic antioxidant defense systems under harsh environmental stresses. Although this field of research has attracted massive interest, it largely remains unexplored, and our understanding of ROS signaling remains poorly understood. In this review, we have documented the recent advancement illustrating the harmful effects of ROS, antioxidant defense system involved in ROS detoxification under different abiotic stresses, and molecular cross-talk with other important signal molecules such as reactive nitrogen, sulfur, and carbonyl species. In addition, state-of-the-art molecular approaches of ROS-mediated improvement in plant antioxidant defense during the acclimation process against abiotic stresses have also been discussed.

Reactive Oxygen Species and Antioxidant Defense in Plants under Abiotic Stress: Revisiting the Crucial Role of a Universal Defense Regulator

Unravelling cadmium toxicity and tolerance in plants: Insight into regulatory mechanisms

https://www.cell.com/trends/biotechnology/pdf/S0167-7799(09)00223-6.pdf

Potential of siderophore-producing bacteria for improving heavy metal phytoextraction

Antioxidant stress responses of plants to cadmium.

Boron (B) nutritional disorders, either deficiency or toxicity, may lead to an increase in reactive oxygen species production, causing damage to cells. Oxidative damage in leaves can be attenuated by supplying silicon (Si). The aim of this study was to assess the effect of increasing foliar B accumulation on cotton plants to determine whether adding Si to the spray solution promotes gains to correct deficiency and toxicity of this micronutrient by decreasing oxidative stress via synthetizing proline and glycine-betaine, thereby raising dry matter production.B deficiency or toxicity increased H2O2 and MDA leaf concentration in cotton plants. H2O2 and MDA leaf concentration declined, with quadratic adjustment, as a function of increased leaf B accumulation. Proline and glycine-betaine leaf concentration increased under B-deficiency and B-toxicity. In addition, production of these nonenzymatic antioxidant compounds was greater in plants under toxicity, in relation to deficient plants. Adding Si to the B spray solution reduced H2O2 and MDA concentration in the plants under nutrient deficiency or toxicity. Si reduced H2O2, primarily in B-deficient plants. Si also increased proline and glycine-betaine concentration, mainly in plants under B toxicity. Dry matter production of B-deficient cotton plants increased up to an application of 1.2 g L- 1 of B. The critical B level in the spray solution for deficiency and toxicity was observed at a concentration of 0.5 and 1.9 g L- 1 of B, respectively, in the presence of Si, and 0.4 and 1.9 g L- 1 of B without it. In addition, the presence of Si in the B solution raised dry matter production in all B concentrations evaluated in this study.Our findings demonstrated that adding Si to a B solution is important in the foliar spraying of cotton plants because it increases proline and glycine-betaine production and reduces H2O2 and MDA concentration, in addition to mitigating the oxidative stress in cotton plants under B deficiency or toxicity. 

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Addition of silicon to boron foliar spray in cotton plants modulates the antioxidative system attenuating boron deficiency and toxicity

This research aimed to evaluate the yield and quality of tomato plants under different managements of salt stress by adopting the partial root-zone saline irrigation (PRSI) system. The experiment was conducted in a greenhouse at the Universidade Federal Rural do SemiÁrido (UFERSA), Mossoró, Rio Grande do Norte (RN), Brazil. The experimental design was completely randomized, with six treatments and four replicates, totaling 24 plots. The treatments consisted of six different irrigation management regimes using low and high saline water (S1–0.5 and S2–5.0 dS·m−1), applied with or without PRSI, such that one side of the root-zone was submitted to saline water whilst the other side was water low salinity irrigated. For treatments T1 (control), T2 (S2 water), and T3 (alternate irrigation system between S1 and S2, with a cycling period of 15 d for each one), the PRSI was not applied; T4 (irrigation with S1 and S2, adopting the PRSI system from phase II to phase IV), T5 (irrigation with S1 and S2 in phase II, alternating in phase III; in phase III the inversion of the remaining water was made until the end of phase IV), and T6 (irrigation with S1 and S2, adopting the PRSI system in phase II, with the water switched between low and high saline water every 15 days, remaining until the end of phase IV) treatments were under the PRSI. The number of fruit per plant, fruit weight, fruit longitudinal and transverse diameter, pulp firmness, soluble solids content, titratable acidity, pH, vitamin C, color relation (a*/b*), lycopene, and β-carotene were determined as parameters for the fruit yield and quality evaluation. Our findings reinforce the importance of the use of PRSI systems followed by irrigation managements without loss of product quality, such as demonstrated by T4 and T5 water managements.

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Influence of Partial Root-zone Saline Irrigation Management on Tomato Yield and Fruit Quality from a Potted-plant Study

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Priscila Lupino Gratão

Papers

Antioxidant stress responses of plants to cadmium.

Addition of silicon to boron foliar spray in cotton plants modulates the antioxidative system attenuating boron deficiency and toxicity

Influence of Partial Root-zone Saline Irrigation Management on Tomato Yield and Fruit Quality from a Potted-plant Study

Addition of silicon to boron foliar spray in cotton plants modulates the antioxidative system attenuating boron deficiency and toxicity

Evaluation of growth and oxidative stress as indicative of salinity tolerance by the invasive tropical aquatic macrophyte tanner grass