Salicylic Acid Stimulates Antioxidant Defense and Osmolyte Metabolism to Alleviate Oxidative Stress in Watermelons under Excess Boron

Abstract

Boron (B) is a microelement required in vascular plants at a high concentration that produces excess boron and toxicity in many crops. B stress occurs widely and limits plant growth and crop productivity worldwide. Salicylic acid (SA) is an essential hormone in plants and is a phenolic compound. The goal of this work is to explore the role of SA in the alleviation of excess B (10 mg L−1) in watermelon plants at a morphological and biochemical level. Excess boron altered the nutrient concentrations and caused a significant reduction in morphological criteria; chlorophyll a, b, and carotenoids; net photosynthetic rate; and the stomatal conductance and transpiration rate of watermelon seedlings, while intercellular carbon dioxide (CO2) was significantly increased compared to the control plants (0.5 mg L−1 B). Furthermore, excess boron accelerated the generation of reactive oxygen species (ROS), such as hydrogen peroxide (H2O2) and induced cellular oxidative injury. The application of exogenous SA significantly increased chlorophyll and carotenoid contents in plants exposed to excess B (10 mg L−1), in line with the role of SA in alleviating chlorosis caused by B stress. Exogenously applied SA promoted photosynthesis and, consequently, biomass production in watermelon seedlings treated with a high level of B (10 mg L−1) by reducing B accumulation, lipid peroxidation, and the generation of H2O2, while significantly increasing levels of the most reactive ROS, OH−. SA also activated antioxidant enzymes, such as superoxide dismutase (SOD), peroxidase (POD), and ascorbate peroxidase (APX) and protected the seedlings from an ROS induced cellular burst. In conclusion, SA can be used to alleviate the adverse effects of excess boron.

Beneficial Features of Biochar and Arbuscular Mycorrhiza for Improving Spinach Plant Growth, Root Morphological Traits, Physiological Properties, and Soil Enzymatic Activities

“…Biochar is the carbon-rich material taken by pyrolysis using various biomasses. Biochar plays an important role in decreasing global warming in the world and reducing atmospheric CO 2 concentrations, as well as improving soil used in agriculture [1][2][3][4][5][6]. Biochar application has been noted to increase the activity of microbes in the soil and improve the physical and chemical properties of the soil [7][8][9][10][11][12][13].Ścisłowska et al [14] observed that biochar treatments improved the quality and productivity of soils.…”

Coupling effects of phosphorus fertilization source and rate on growth and ion accumulation of common bean under salinity stress

“…Besides, Curtin, Steppuhn & Selles (1993) reported that increased Na + and Ca 2+ concentrations in the soil solution can contribute to raised ionic strength in the soil that can improve P retention. The other elements and ions, including sodium (Na + ), chlorine (Cl -), and boron (B) have particularly toxic effects on plants (Moustafa-Farag et al, 2020). The accumulation of sodium causes disturbances of cell membranes permeability, followed by osmotic stress and cell death .…”

Melatonin Counteracts Drought Induced Oxidative Damage and Stimulates Growth, Productivity and Fruit Quality Properties of Tomato Plants

“…Water deficit is thought to be one of the environmental factors that dramatically restrict plant growth, development, and yield [1][2][3][4]. It causes several interconnected responses leading to considerable damages at morphological, physiological, biochemical, and molecular levels [5][6][7][8][9]. Among these effects, water deficit causes altering of leaf water status, hindering stomatal conductance, reducing nutrient uptake, degradation of leaf pigments and photosynthesis depression [9][10][11].…”