Silicon Induces Heat and Salinity Tolerance in Wheat by Increasing Antioxidant Activities, Photosynthetic Activity, Nutrient Homeostasis, and Osmo-Protectant Synthesis

Abstract

Modern agriculture is facing the challenges of salinity and heat stresses, which pose a serious threat to crop productivity and global food security. Thus, it is necessary to develop the appropriate measures to minimize the impacts of these serious stresses on field crops. Silicon (Si) is the second most abundant element on earth and has been recognized as an important substance to mitigate the adverse effects of abiotic stresses. Thus, the present study determined the role of Si in mitigating adverse impacts of salinity stress (SS) and heat stress (HS) on wheat crop. This study examined response of different wheat genotypes, namely Akbar-2019, Subhani-2021, and Faisalabad-2008, under different treatments: control, SS (8 dSm−1), HS, SS + HS, control + Si, SS + Si, HS+ Si, and SS + HS+ Si. This study’s findings reveal that HS and SS caused a significant decrease in the growth and yield of wheat by increasing electrolyte leakage (EL), malondialdehyde (MDA), and hydrogen peroxide (H2O2) production; sodium (Na+) and chloride (Cl−) accumulation; and decreasing relative water content (RWC), chlorophyll and carotenoid content, total soluble proteins (TSP), and free amino acids (FAA), as well as nutrient uptake (potassium, K; calcium, Ca; and magnesium, Mg). However, Si application offsets the negative effects of both salinity and HS and improved the growth and yield of wheat by increasing chlorophyll and carotenoid contents, RWC, antioxidant activity, TSP, FAA accumulation, and nutrient uptake (Ca, K, and Mg); decreasing EL, electrolyte leakage, MDA, and H2O2; and restricting the uptake of Na+ and Cl−. Thus, the application of Si could be an important approach to improve wheat growth and yield under normal and combined saline and HS conditions by improving plant physiological functioning, antioxidant activities, nutrient homeostasis, and osmolyte accumulation.

Mitigation of Salinity Stress and Lead Toxicity in Maize by Exogenous Application of the Sorghum Water Extract

“…Lead stress induces phytotoxicity in leaves by degrading chlorophyll contents, and it also damages the photosynthetic apparatus, therefore leading to a reduction in chlorophyll synthesis . Salinity stress also reduced the synthesis of photosynthetic pigments, which could be attributed to increased ROS production (Table ) that damages the photosynthetic apparatus and degrades chlorophyll, resulting in a reduction in chlorophyll synthesis. , The exogenous supply of SWE improved the synthesis of photosynthetic pigments under both stresses, which is consistent with the findings of Tahira et al They found that the application of allelochemicals improves chlorophyll synthesis by reducing ROS production and decreasing the activity of chlorophyll degrading enzymes.…”

“…This reduction in growth was linked with increased EL, MDA, and H 2 O 2 production and disturbed nutrient homeostasis and antioxidant activities (Figures and ). Lead is a serious toxic that disturbs the soil microbial activity and plant functioning, resulting in a reduction in plant growth. , Salinity stress also induced ionic toxicity and increased ROS production (Table ), which caused a marked reduction by decreasing nutrient and water uptake . The foliar application of SWE appreciably improved the root and shoot growth of maize plants growing under Pb and salinity stress (Figures and ).…”

“…Lead and salinity stress increased EL due to an increase in the levels of MDA and H 2 O 2 production. Abiotic stresses induce oxidative stress and result in increases in EL owing to an increase in MDA and H 2 O 2 production . Nonetheless, foliar-applied SWE ameliorated Pb and salinity-induced oxidative damages and reduced the EL by decreasing MDA and H 2 O 2 production .…”

“…Abiotic stresses induce oxidative stress result in increases in EL owing to an increase in MDA and H 2 O 2 production. 53 Nonetheless, foliar-applied SWE ameliorated Pb and salinity-induced Data are the mean values of three replications (n = 3) along with standard errors (SE). The lowercase letters indicate the significant differences among means (LSD test).…”

Effects of exogenous brassinolide and AM fungi on growth, photosynthetic characteristics and antioxidant enzyme system of Leymus chinensis under salt and alkali stress

“…This study reported that contents of chlorophyll a+b in L. chinensis was significantly decreased under salt-alkali stress. At the same time inoculated AM fungus inoculation significantly increased the synthesis of both chlorophyll contents possibly by increasing the uptake of important nutrients (iron and magnesium) that are considered to play a fundamental role in chlorophyll synthesis (Cao et al, 2021;Aouz et al, 2023;Khan et al, 2023b). This study further showed that under saline-alkali stress, gas exchange parameters (Pn, Gs, Tr) and chlorophyll fluorescence parameters (Fv/Fm, ΦPSⅡ, qP), were significantly decreased.…”