The Alleviative Effects of Salicylic Acid on Physiological Indices and Defense Mechanisms of Maize (Zea Mays L. Giza 2) Stressed with Cadmium

Abstract

The present study evaluated the physiological and biochemical mechanisms through which exogenous salicylic acid (SA) mitigates cadmium (Cd) stress in maize. The different concentrations of Cd included 0, 5, 10 µM CdCl 2 .3H 2 O. Half of plants received salicylic acid as a soil drench. Results showed that Cd exposure reduced chlorophyll contents, chlorophyll fluorescence, photosynthetic rate and activity of catalase (CAT). However, Cd stress enhanced nonphotochemical quenching (NPQ), the production of malondialdehyde (MDA) and activities of key antioxidant enzymes superoxide dismutase (SOD), ascorbate peroxidase (APX), guaiacol peroxidase (POD). The increased activities of antioxidant enzymes and concentration of MDA were reduced by exogenous application of SA as a soil drench. Our research proves that SA, as a novel endogenous plant hormone exerts beneficial physiological effects on plants as it has a dual role in scavenging active oxygen species (AOS) and modulating redox balance to enhance photosynthetic performance in cadmium-stressed maize plants. It was concluded that SA improved plant tolerance under Cd contamination and may have alleviated the inhibitory effect of Cd on photosynthesis by protecting maize plants against oxidative damage as indicated by the marked decline in net photosynthetic rates, quantum yield and chlorophyll content as well as alteration of antioxidants activity and accumulation of MDA. Collectively, results of the present study provide an insight into the alleviative role of SA in Cd-stressed maize and propose SA as a potential candidate in mitigating Cd toxicity.

Bacillus pumilus induced tolerance of Maize (Zea mays L.) against Cadmium (Cd) stress

“…Present study depicted an increased SOD and POD activity at higher concentrations suggesting that both of these enzymes act simultaneously to avert the formation of OH ions and remove H 2 O 2 71 , 73 . Therefore, the increased enzymatic (particularly SOD) activity at a higher concentration of Cd is considered a good indication for defensive mechanism stimulation 74 . In addition to this, it was observed in a study that the SOD activity was higher at the lower concentration of Cd in soil (20–25 mg/kg), normal when the concentration ranges between 50 and 75 mg/kg Cd in the soil and start to decrease when the soil Cd toxicity levels reached to 100 mg/kg 71 .…”

Impact of salicylic acid and sodium hydrosulfide applied singly or in combination on drought tolerance and grain yield in wheat plants

“…The influence of SA on chlorophyll levels in drought‐stressed plants may vary based on factors such as the plant species (Abdelaal et al., 2020), the dosage of SA applied, and the method of application (Moustakas et al., 2021). SA enhances plant defense mechanisms by improving photosynthetic efficiency and mitigating the accumulation of free radicals in stressed plants (El Dakak & Hassan, 2020). The adverse impact of DS on wheat plants is evident in the reduction of maximum Fv/Fm and chlorophyll content.…”

Effectiveness of Seed Priming and Soil Drench with Salicylic Acid on Tomato Growth, Physiological and Biochemical Responses to Severe Water Deficit

“…This is because they are cost-effective and easy to use in locally grown varieties. The foliar application of SA has also been shown to be an adequate strategy to mitigate abiotic stresses (El Dakak and Hassan 2020;Liu et al 2021). However, the comparative efficiency of methods SA application has not been well tested yet, even there are contradictory reports on seed priming, root or foliar efficiency of SA application (Souri and Tohidloo 2019).…”