Hesham F. Alharby

Seed priming mitigates the negative effects of seed deterioration and abiotic stresses by increasing vigor with enhanced germination rate and percentage, as well as seedling growth. This study aimed to enhance the post-storage vitality of sesame by seed priming techniques and alleviate the detrimental effects of salinity, drought, and temperature stresses during germination and seedling growth stages. Seed priming techniques employed were halopriming (KCl 1.5%, CaCl ₂ 2%) _, hormopriming (GA ₃ 50 mg kg ⁻¹ ), priming with MLE (3%), and hydropriming in comparison to untreated dry seed as a control. Primed and control sesame seeds were exposed to different salinity (0, 2.5, 5 dS m ⁻¹ ), water potential (0, −0.2, −0.4 MPa), and temperature (10, 20, 30, 40 °C) stresses during germination and seedling growth stages. Outcomes showed that incremental drought and salinity reduced the germination and seedling growth of post-storage sesame seeds. No germination occurred at 10°C, while maximum germination and seedling growth was found at 30°C with a simultaneous decrease at 40°C. Halopriming (KCl or CaCl ₂ ) and hormopriming (GA ₃ ) enhanced post-storage vigor of sesame seeds was attributed to increase in final germination and its rate, germination energy, and its index. The enhanced vigor also decreased the time to 50% germination (T ₅₀ ) and mean germination time (MGT) under stress conditions. The post-priming improved vigor of sesame seeds was attributed to better membrane repairs owing to a decrease in seed leachates, MDA, and H ₂ O ₂ contents, as well as increased seedling fresh and dry weights under each stress type. A positive association of seed vigor with germination and seedling growth attributes was also found. In conclusion, halopriming (CaCl ₂ or KCl) and hormopriming (GA ₃ ) enhanced the post-storage vitality of sesame seeds and mitigated the detrimental effects of abiotic stresses during germination and seedling stages.

The bioavailability of heavy metals in soil is a crucial factor in determining their potential uptake by plants and their subsequent entry into the food chain. Various methods, including traditional chemical extractants and the diffusive gradients in thin films (DGT) technique, are employed to assess this bioavailability. The bioavailability of heavy metals, particularly cadmium (Cd) and lead (Pb), is also influenced by soil texture and their concentrations in the soil solution. The primary objectives of this experiment were to compare and correlate the assessment of the Cd and Pb bioavailability using the DGT technique and traditional extractants across two soil textural classes: sandy clay loam (SCL) and clay loam (CL) at two contamination levels: aged contaminated (NC) and artificially contaminated (AC). The specific objectives included assessing the bioavailability of Cd and Pb at different growth stages of the wheat plant and correlating the DGT-based bioassessments of Cd and Pb with their concentrations in various plant parts at different growth stages. This study also compared the effectiveness of the DGT method and traditional extraction techniques in assessing the bioavailable fractions of Cd and Pb in soil. The regression analysis demonstrated strong positive correlations between the DGT method and various extraction methods. The results showed that the wheat plants grown in the AC soils exhibited lower root, shoot, and grain weights compared to those grown in the NC soils, indicating that metal contamination negatively impacts plant performance. The concentrations of Cd and Pb in the wheat tissues varied across different growth stages, with the highest levels observed during the grain filling (S3) and maturity (S4) stages. It is concluded that the in situ assessment of Cd and Pb though DGT was strongly and positively correlated with the Cd and Pb concentration in wheat plant parts at the maturity stage. A correlation and regression analysis of the DGT assessment and traditional extractants showed that the DGT method provides a reliable tool for assessing the bioavailability of Cd and Pb in soils and helped in developing sustainable soil management strategies to ensure the safety of agricultural products for human consumption.

Groundwater, a primary source of freshwater on Earth, is rapidly declining due to natural and anthropogenic activities. This study aimed to investigate the spatial distribution of dissolved organic matter (DOM) and heavy metals (HMs) in two municipal groundwater networks (A and B) from tube wells to taps in an industrial city, Faisalabad. The results showed that parameters such as color, turbidity, pH, EC, TDS, Ca²⁺, Mg²⁺, CO₃²⁻, HCO₃⁻, Cl⁻, CaCO₃, Na+, and NO₃⁻ were within the permissible limits set by the World Health Organization (WHO) and Pakistan Environmental Quality Standards (PEQSs). However, parameters like DO and COD exceeded standard values along the routes. Odor, taste, temperature, BOD, NH₄⁺, T. coli, and F. coli surpassed acceptable levels at the tap end of both networks. Fluorescence EEM-PARAFAC spectra were analyzed at an excitation wavelength of 220–500 nm and emission wavelength of 240–550 nm, revealing UVA-humic-like (C1–C2) and UVC-humic-like (C3) components in the DOM. Based on fluorescence intensity, DOM was dominated by C2 > C1 > C3 compounds in both networks. The mean concentrations of HMs, including Cu, Zn, and Fe, fell below the prescribed limits in both networks. However, concentrations of Pb (A: 0.015–0.028 mg/L), (B: 0.013–0.027 mg/L), and Cd (A: 0.004–0.006 mg/L), (B: 0.005–0.008 mg/L) exceeded permissible limits from tube wells to taps. Moreover, C1 demonstrated a significant positive correlation with Cd and Cu in networks A and B, respectively. Furthermore, C2 displayed a significant positive correlation with Cd in network A. This study concludes that the groundwater in both networks (A and B) is contaminated by agricultural runoff, industrial and sewage water, plumbing materials, and eroded pipelines. As a result, the water is unsafe for cooking and drinking, posing risks of kidney, lung, and bladder cancers. Therefore, this study urgently recommends pipeline reconstruction and the implementation of proper groundwater remediation approaches before these sources are used for drinking.

Background: Potassium (K) is an essential macronutrient, improves rice yield and contributes to salt stress tolerance. This study determined the best potassium (K) application level on yield formation and the saline resistance capability of rice under salinity field conditions of central Vietnam. Methods: Experiments were comprised of five K fertilizer application rates (0, 25, 50, 75 and 100 kg K2O/ha) and two rice varieties, viz, OM8104 and MNR3 for two growing seasons of 2021 and 2022. All treatments were arranged in a split-plot design with 3 replicates in Duy Vinh commune, Duy Xuyen district, Quang Nam province. Result: Potassium application affected the number of panicles per unit area, filled grain per panicle and actual grain yield of both rice varieties in both seasons under saline condition. Application of 50 kg K2O/ha reduced the soil salinity over the monitoring periods compared to the other K rates. EC values of soil were significantly higher during the hot season than the wet season showing high temperature effects. Application of 50 kg K2O/ha also accumulated maximum dry matter at different crop stages and produced the highest rice yield with 7.57 and 5.25 tons/ha for OM8104 and 7.35 and 5.18 tons/ha for MNR3 in both wet and hot seasons respectively. The harvest index could not affect significantly by K application irrespective of seasons and varieties. These increases in actual grain yields using 50 kg K2O/ha were attributed to increased filled grains per panicle, accumulation of high K+ content and K+/Na+ ratios in rice varieties in both seasons under saline field condition.

Salinity and cadmium (Cd) contamination of soil are serious environmental issues threatening food security. This study investigated the role of salicylic acid (SA) and potassium (K) in enhancing the resilience of quinoa against the combined stress of salinity and Cd. Quinoa plants were grown under NaCl (0, 200 mM) and Cd (0, 100 µM) stress, with the addition of 0.1 mM SA and 10 mM K, separately or in combination. The joint stress of Cd and NaCl caused >50% decrease in plant growth, chlorophyll contents, and stomatal conductance compared to the control plants. The higher accumulation of Na and Cd reduced the uptake of K in quinoa tissues. The joint stress of salinity and Cd caused an 11-fold increase in hydrogen peroxide and 13-fold increase in thiobarbituric acid reactive substances contents, and caused a 61% decrease in membrane stability. An external supply of 0.1 mM SA and 10 mM K helped plants to better adapt to salinity and Cd stress with less of a reduction in plant biomass (shoot 19% and root 24%) and less accumulation of Na and Cd in plant tissues. The activities of superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), and ascorbate peroxidase (APX) were enhanced by 11-fold, 10-fold, 7.7-fold, and 7-fold, respectively, when SA and K were applied together to the plants subjected to the joint stress of Cd and salinity. Based on the values of the bioconcentration factor (>1), the translocation factor (<1), and the higher tolerance index, it was clear that Cd-contaminated, salty soils could be stabilized with quinoa under the combined supply of SA and K.