Silicon and Salinity: Crosstalk in Crop-Mediated Stress Tolerance Mechanisms

Abstract

Salinity stress hinders the growth potential and productivity of crop plants by influencing photosynthesis, disturbing the osmotic and ionic concentrations, producing excessive oxidants and radicals, regulating endogenous phytohormonal functions, counteracting essential metabolic pathways, and manipulating the patterns of gene expression. In response, plants adopt counter mechanistic cascades of physio-biochemical and molecular signaling to overcome salinity stress; however, continued exposure can overwhelm the defense system, resulting in cell death and the collapse of essential apparatuses. Improving plant vigor and defense responses can thus increase plant stress tolerance and productivity. Alternatively, the quasi-essential element silicon (Si)—the second-most abundant element in the Earth’s crust—is utilized by plants and applied exogenously to combat salinity stress and improve plant growth by enhancing physiological, metabolomic, and molecular responses. In the present review, we elucidate the potential role of Si in ameliorating salinity stress in crops and the possible mechanisms underlying Si-associated stress tolerance in plants. This review also underlines the need for future research to evaluate the role of Si in salinity stress in plants and the identification of gaps in the understanding of this process as a whole at a broader field level.

Silicon Confers Soybean Resistance to Salinity Stress Through Regulation of Reactive Oxygen and Reactive Nitrogen Species

“…Salt stress also causes growth inhibition in all plants because it affects all processes necessary for a plant to survive, such as growth, photosynthesis, energy metabolism, and protein synthesis (Parida and Das, 2005;Jan et al, 2018;Ahmad et al, 2019). Accumulation of Na + and Cl − in the plant cell accelerates programmed cell death due to the lipid peroxidation of cellular membranes caused by an imbalance of ions (Abdel Latef et al, 2017;Abdel Latef et al, 2019b;Khan et al, 2019). Plants are sessile organisms, and so have developed a selfdefense system to cope with abiotic and biotic stress conditions (Zhu, 2016).…”

Role of Silicon in Mediating Phosphorus Imbalance in Plants

“…Si can strengthen plant resistance to abiotic and biotic stresses via physical and physiological biochemical mechanisms. Recently, several authors have systematically reviewed research progress on the elucidation of mechanisms of Si-mediated alleviation of biotic and abiotic stresses in plants [ 2 , 3 , 4 , 5 , 6 , 7 ]. In these reviews, however, the beneficial effects of Si on nutrient imbalance have received relatively little attention.…”

Salt-tolerance induced by leaf spraying with H2O2 in sunflower is related to the ion homeostasis balance and reduction of oxidative damage

“…This increase in the production of ROS (under stress conditions) can lead to an imbalance of redox homeostasis, characterizing oxidative stress, and consequently causing disturbances in cell structure and metabolism ( Khan et al., 2019 ). However, H 2 O 2 priming induces an increase in antioxidant activity by increasing the level of transcripts and expression of antioxidant enzyme genes, such as superoxide dismutase, catalase, ascorbate peroxidase, guaiacol peroxidase and others ( Azevedo Neto et al., 2005 ; Gondim et al., 2012 ; Hossain et al., 2015 ; Savvides et al., 2016 ).…”

“…Under these conditions, both photochemical and biochemical phases of photosynthesis can be negatively affected (Melo et al, 2020). Besides, salinity can increase lipid peroxidation, and consequently reduce the integrity of cell membranes, besides it causes an imbalance between the production and the scavenging of the reactive oxygen species (ROS) (Khan et al, 2019). This imbalance (oxidative stress situations) can cause cell damage, since ROS are very powerful oxidizers and can react with almost all components of living cells, producing severe damage to lipids, proteins and nucleic acids (Khan et al, 2019).…”