How nitrogen (N) levels affect agronomic performance and the nutrient utilization process in wheat grown in rainfed coastal saline soils remains largely unknown. This study investigated the influence of three N supply treatments (0, 100, and 200 kg/ha) on the growth and accumulation of P, Ca, Mg, K, Na, Zn, Fe, and Se of eight wheat genotypes across two consecutive seasons (2020–2021, 2021–2022) in a rainfed coastal field. Both agronomic performance and nutrient accumulation were significantly affected by N supply and genotypic effects. The increased total accumulation of nutrients was mainly due to enhanced agronomic performance by N supply. Grain Zn and Fe concentrations increased, while the grain Se concentration decreased with the N supply increasing. Genotype “Jimai 775” exhibited both a higher grain yield and a higher nitrogen agronomic efficiency among the tested genotypes. The association among agronomic traits and nutrient accumulation was obviously modified by the N supply, as revealed by principal component analysis, correlation analysis, and stepwise multiple regression models. These findings suggest that both the N supply level and genotypic differences should be taken into consideration to enhance nutrient utilization in wheat cultivated in coastal saline soils.

Petroleum hydrocarbons (PHC) are organic pollutants that pose serious health risks to humans and the environment. Treating soils contaminated with these persistent pollutants is a global concern that is challenging to implement effectively. Synergistic remediation strategies, particularly those involving plants and functional endophytic bacteria, offer ecologically sustainable approaches for remediating PHC-contaminated soil and thus hold broad application prospects. This review collected the literature from databases including Elsevier, Web of Science, PubMed, and CNKI, using keywords such as endophytic bacteria, petroleum hydrocarbons, plants, microorganisms, polycyclic aromatic hydrocarbons, and alkanes. After screening the titles, abstracts, and secondary headings, 123 articles were selected for narrative synthesis. It systematically elaborates on the types, functions, sources, and distribution characteristics within plants of hydrocarbon-degrading endophytic bacteria. It comprehensively summarizes the key molecular pathways involved in the bacterial degradation of alkanes and polycyclic aromatic hydrocarbons (PAHs). Furthermore, from four dimensions—PHC metabolism modes, plant growth promotion (PGP), production of biosurfactants (PBS), and horizontal gene transfer—this article innovatively analyzes the mechanisms underlying the synergistic remediation of petroleum hydrocarbon-contaminated soil through functional bacterium–plant interactions. Finally, the review outlines future research directions in the field, providing a theoretical foundation and practical pathways for advancing green remediation strategies for PHC-polluted soil.

Soil salinization is one of the most important factors limiting the sustainable development of global agriculture. As the core driving force of the soil carbon cycle, soil-carbon-metabolism-related enzyme activity is very important for soil ecological balance and fertility enhancement. To explore the spatial and temporal variation characteristics and coupling mechanisms of soil water, salt, nutrients and enzyme activities in different salinized wheat fields in the Yellow River Delta, field experiments were conducted in Dongying City, Shandong Province. The results showed that the soil moisture content of the low-salt wheat field was higher and that the salt content of three wheat fields was concentrated in the 0–20 cm and 80–100 cm soil layers. Here, soil nutrients and enzyme activities are concentrated in the 0–20 cm topsoil, with significant differences in different degrees among salinized wheat fields at the different growth stages of wheat. Overall, invertase activity (S-SC) and amylase activity (S-AL) presented a trend of low salt > high salt > medium salt, while cellulase activity (S-CL) presented a trend of medium salt > low salt > high salt. Redundancy analysis showed that available potassium (AK) (67.6%) and electric conductivity (EC) (21.2%) in the low-salinity wheat field, total nitrogen (TN) (48.6%) and AK (28.8%) in the medium-salinity wheat field, and EC (67%) and soil organic matter (SOM) (19%) in the high-salinity wheat field contributed the most to soil enzyme activity. This study provides a theoretical basis for the management and sustainable development of different salinized wheat fields in the Yellow River Delta.

Magnesium (Mg) release (MGR) proteins play a crucial role in maintaining Mg²⁺ homeostasis in plant cells. However, MGR family genes have not yet been explored in crops. This study identified the wheat MGR (TaMGR) family members via BlastP alignment. A total of 15 MGR genes were mapped to 12 chromosomes. Cis-element prediction in the promoter region revealed that the ABA-responsive element (ABRE) was 100% conserved among all family members. Collinearity analysis indicates that MGR genes in monocot plants may have higher conservation compared to dicot plants. Expression profiling analyses uncovered the expression patterns of TaMGR genes across diverse tissues and under various stresses. Our results demonstrated that TaMGR5D and TaMGR5A.2 were significantly induced by both powdery mildew and stripe rust pathogen infections, whereas TaMGR4A transcript levels were upregulated in response to drought, heat and their combined stress. These findings indicate that TaMGRs may contribute coordinately to the regulation of wheat growth and development as well as adaptive responses to adverse conditions through member-specific expression patterns. This study systematically identified and analyzed the evolution and expression regulation characteristics of TaMGRs, providing a theoretical basis for in-depth research on the functional mechanisms of the TaMGRs and for improving the Mg use efficiency and stress adaptability of wheat via molecular approaches.

Oilfield-wetland zones are ecologically fragile landscapes where petroleum extraction, traffic, and agricultural activities may jointly affect soil metal accumulation. In this study, surface soils from oilfield-wetland patches in the Yellow River Delta were analyzed for Cr, Co, Ni, Cu, Zn, Cd, and Pb, together with selected soil properties. The concentrations of Cr, Co, Ni, Cu, Zn, Cd, and Pb ranged from 47.11 to 106.72, 11.01 to 23.53, 27.61 to 64.28, 6.41 to 60.45, 10.41 to 190.95, ND to 0.37, and 16.53 to 104.58 mg/kg, respectively, and were below the Chinese agricultural soil risk-screening values. Ni exceeded the local background value in all samples, while Pb, Co, Cr, and Cu showed frequent background exceedance, indicating limited enrichment rather than regulatory risk. Spatial differences were element-specific, with Cu differing significantly between Gudao and Xianhe towns and Zn tending to be higher away from oil wells and in vegetated zones. Correlation and PCA results suggested possible influences from both natural processes and anthropogenic activities. Pollution and ecological risk indices indicated low overall risk, but Pb enrichment, consistent Ni background exceedance, and localized Cd-related ecological risk require continued monitoring.