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Soil salinization has increased over recent years and is negatively affecting crop productivity. Nutrient application is an effective strategy to improve abiotic stress tolerance in crops. The application of coated fertilizers has emerged as an excellent approach to mitigate the adverse impacts of soil salinity. Therefore, the present study was conducted to determine the effects of zinc and sulfur coated urea on the performance of wheat growing under saline conditions. The study comprised of diverse salinity stress levels; 0, 6 and 12 dS m-1, cross combined with normal urea (NU), zinc coated urea (ZCU) and sulfur coated urea (SCU). Salinity stress reduced wheat yield by impairing leaf water status, reducing photosynthetic pigments, osmolytes accumulation, potassium (K) and nitrogen (N) uptake while increasing sodium (Na) and chloride (Cl) uptake and hydrogen peroxide (H2O2), malondialdehyde (MDA) and electrolyte leakage (EL) accumulation. The application of ZCU increased the wheat yield by enhancing photosynthetic pigments, leaf water status, antioxidant activities, osmolytes accumulation, and reducing H2O2, MDA and EL accumulation. Furthermore, the significant increase in growth and yield of wheat with ZCU and SCU was also linked with improved K and N uptake, higher nitrogen use efficiency (NUE) and reduced Na and Cl concentration. Thus, the application of ZCU could be an effective approach to improve wheat productivity under saline conditions.

Salinity stress (SS) is a major and increasing abiotic stress adversely affecting plant growth and productivity across the globe. The application of organic amendments (OA) is considered to be an important practice to mitigate the adverse impacts of SS. Therefore, this study was performed to assess the impact of different OA on growth, physiology and anti-oxidant activities of maize plants grown under SS. The study was comprised of diverse SS levels; 0, 6 and 12 dS m-1, and different OA; control, cow manure (CM: 5%), sugarcane pressmud (SPM: 5%) and combination of CM (2.5%) + SPM (2.5%). The study was conducted in a completely randomized design with factorial arrangement having three replications. The results indicated that SS reduced the growth and biomass production, relative water contents (RWC), chlorophyll contents, free amino acids (FAA), total soluble proteins (TSP) and increased the electrolyte leakage (EL: 40.92%), hydrogen peroxide (H2O2: 68.49%), malondialdehyde (MDA: 42.13%), and catalase (CAT: 34.24%) and ascorbate peroxide (APX: 25.70%). The application of OA significantly improved the maize growth under SS. However, the application of SPM (5%) significantly increased growth and biomass production by decreasing EL, MDA and H2O2 accumulation and increasing RWC, chlorophyll, CAT, POD, and anthocyanin, TSP and FAA. These findings suggest that application of SPM improved the growth and biomass production of maize by improving anti-oxidant activities, photosynthetic pigments, TSP, FAA reducing lipid peroxidation and EL.

Background Climatic changes are the most important abiotic factor affecting plant growth, crop quality and nutritional value. Plants exposed to thermal stress respond by accumulation of secondary metabolites/molecules (SMs). Tomato (Solanum lycopersicum) is a cosmopolitan crop, eaten by most of the world’s people because it is highly nutritious plant. It is cultivated in more than 16 thousand hectares in Saudi Arabia and thus is influenced by extreme climatic changes. Objective In the current study, the phytochemical effect of thermal stress was investigated in seedlings of S. lycopersicum. Such information will be very helpful in developing more tolerant tomato cultivars in a climate change scenario. Methods Seedlings of S. lycopersicum were subjected to heat shock; HS1 and HS2 (45 and 50 °C) and cold shock; CS (4 °C) in comparison to control; Con (25 °C). Phenolic compounds, flavonoids, total phenolic content (TPC), total flavonoid content (TFC) and antioxidant activity were estimated under the four temperature treatments. Results Using 23 standards (17 phenolic and six flavonoids), HPLC resulted in the estimation of 16, 20, 15 and 18 compounds for Con, CS, HS1 and HS2, respectively. Differences in the amounts of total phenolics, and total flavonoids were strongly correlated to thermal stress. CS plants exhibited the highest number of signals and the highest absolute quantities of total phenolics, flavonoids and sum of both. The major peaks of phenolics were (Chlorogenic acid, Resvertol), (Vanillic acid, Benzoic acid, Quinol), (Vanillic acid, Benzoic acid) and (Vanillic acid, Benzoic acid) for Con, CS, HS1 and HS2, respectively. The major peaks of flavonoids were (Quercetin, Myricetin), (Quercetin, Rutin), (Quercetin, Rutin, Catechin) and (Quercetin) for Con, CS, HS1 and HS2, respectively. CS plants contain the highest amounts of Benzoic acid (8010.37 mg/kg FW) and Quercetin (2319.48 mg/kg FW). The highest TPC (131 mg GAE/100 g FW) and TFC (61 mg QE/100 g FW) were determined in the case of CS plants. In terms of IC50s, the CS plants showed the highest antioxidant activities (lowest values) in both of DPPH (467.73 µM TE/100 g FW) and ABTS (8.97 µM TE/100 g FW) assays. Conclusions Our findings supported that the complexity and quantity of phenolics and flavonoids in tomato’s extract are strongly related to thermal stress. Additionally, the CS plants demonstrated more desirable phytochemical profile over the other treatments. CS plants exhibited higher number, absolute amounts of SMs, higher TPC and TFC than those of Con, HS1 and HS2 plants. Additionally, CS plants showed higher antioxidant activity than that of both HS1 and HS2 plants. Such results are very useful in justifying mechanism of tolerance in tomato plant to thermal stress in the context of climate change. Additional research has turned on to reveal molecular response of tomato to such thermal stress.