The Yangtze River Basin serves as the primary rapeseed-producing region in China, accounting for over 80% of the national output, yet it is severely impacted by waterlogging, resulting in yield reductions of 17–42.4%. This study investigated the effects of pelleting treatments on growth and waterlogging resistance in Brassica napus varieties Xiangzayou 787 and Fanmingyoutai. Conventional pelleting agents were augmented with waterlogging resistance agents, surfactants, and amino acids as growth-promoting reagents. The results demonstrated that melatonin at $5.0\times {10}^{-5}$ mol/L significantly enhanced rapeseed growth and stress resistance. Specifically, for Xiangzayou 787, root fresh weight increased by 16.9% and stem diameter by 30.6%; for Fanmingyoutai, stem diameter increased by 16.9% and leaf length by 12.3%. The freezing injury index decreased by 90.9% for Xiangzayou 787 and 50% for Fanmingyoutai. The waterlogging injury index was reduced by 43.5% for Xiangzayou 787 and 30.4% for Fanmingyoutai, with stem diameter increasing by 30.6% and 16.5% in the respective varieties. The disease index decreased by 63.2% for Xiangzayou 787 (incidence reduced to 20.5%) and up to 57.1% for Fanmingyoutai (incidence reduced to 23.3%). Under this treatment, soluble protein content in Fanmingyoutai reached 20.37%, representing a 20.37% increase relative to the control. Peroxidase (POD) and superoxide dismutase (SOD) activities exceeded control levels, exhibiting an initial rise followed by a decline; malondialdehyde (MDA) content gradually increased; catalase (CAT) activity and soluble protein content showed an initial increase then decrease. The increase in relative electrical conductivity was reduced by 20.8% for Xiangzayou 787 and 17.3% for Fanmingyoutai. Yield per plant increased by 10.2% for Xiangzayou 787 and 35.6% for Fanmingyoutai. The newly developed pelleting formulation integrates waterlogging resistance agents, surfactants, and amino acids, unlike traditional agents, and proves effective for both hybrid and conventional rapeseed varieties. It enhances waterlogging resistance, promotes growth, improves disease resistance, and elevates seed quality while being cost-effective and simple for production and field application. This approach significantly boosts yield and supports productivity enhancement in southern rice fields, thereby improving rapeseed output and oil supply.

The effects of biochar on soil N₂O emissions remain contentious, and the microbiological processes involved are not yet fully understood. Arbuscular mycorrhizal (AM) fungi, key players in soil nitrogen (N) cycling, may mediate the impact of biochar on plant N uptake and N₂O emissions, but this interaction remains unclear. This study involved a two-year field experiment to examine how varying biochar application rates affect soil microbial communities, particularly AM fungi at rainfed maize (Zea mays L.) farmland, and to assess how AM fungi influence soil N₂O emissions and maize growth under biochar addition with two AM fungi treatments (with and without suppression of native AM fungi). The results revealed that biochar significantly enhanced soil microbial diversity, especially the variety and richness of AM fungi. Biochar addition improved soil physicochemical parameters, including soil water content, bulk density, and inorganic N availability. Biochar also decreased AOA and AOB gene abundances, increased AM fungal gene abundances, lowered (nirK + nirS)/nosZ ratio, and reduced soil N₂O emissions. Suppression of native AM fungi increased N₂O emissions throughout the rainfed maize growing period, accompanied by a higher (nirK + nirS)/nosZ ratio. Biochar addition combined with non-suppressed AM fungi promoted maize growth, with the highest yield observed at 20 t ha⁻¹ biochar. Overall, biochar decreased N₂O emissions and strengthened the performance of AM fungi in rainfed maize farmland, highlighting the vital role of AM fungi s in soil N cycling under biochar addition. This study offers a scientific basis for using biochar in reducing N₂O emissions and increasing crop yield in dry farmland.

Rapeseed is the largest self-produced oil crop in China which plays an important role in ensuring the safety of edible oil. However, its current per unit yield is far below Canada and Europe. In this study, selenium fertilizer and other micro fertilizers were sprayed on Xiangzayou 787 at the seedling stage. The results showed that the yield per plant increased 24.3% with sprayed selenium compared to the control (CK). Compared with the CK, the chlorophyll content in leaves at the flowering stage was significantly increased by 20.8%, and the soluble sugar content in the silique wall and seeds at the maturity stage was significantly increased and increased by 62.1% during the budding stage. The functional leaves of Xiangzayou 787 with the sprayed selenium fertilizer and the CK were used as raw materials for absolute quantitative transcriptome sequencing analysis. Accompanied with bioinformatics analysis, six differential genes which affect growth were discovered. The expression level of the protein phosphatase 2C gene in the silique wall was significantly higher than that of the CK. The PP2C78 gene was significantly positively correlated with the chlorophyll and soluble sugar content in leaves and the correlation coefficients were 0.539 and 0.547. According to gene expression levels, yield, and physiological indicators, PP2C78 may be a key functional gene affecting rapeseed yield. In this study, selenium fertilizer was found to be an excellent foliar fertilizer for rapeseed; the PP2C78 gene may be helpful for analyzing the yield increasing mechanism and used as a reference for screening new foliar fertilizers.

The accumulation of polylactic acid nano-plastics (PLA-NPs) in saline–alkali soils poses a potential threat to crop growth; however, the underlying toxicological mechanisms remain poorly understood. We conducted a hydroponic experiment to investigate the effects of polylactic acid (PLA) NPs (100 and 500 mg L⁻¹) under conditions both in the presence (50 mmol L⁻¹ NaCl) and absence of salt stress on maize seed germination, seedling growth, physiological characteristics, and transcriptomic responses. The results showed that exposure to PLA-NPs, particularly at a high concentration (500 mg L⁻¹), significantly inhibited seed germination and seedling growth. Compared to the low concentration (100 mg L⁻¹) of PLA-NPs, the high concentrations (500 mg L⁻¹) reduced the germination percentage by 25.0% and fresh weight by 25.8% and increased root MDA (6.7%), SOD (30.0%), POD (6.3%), ASA (13.4%), and GSH (13.1%). Under the same concentration of the PLA, PLA + NaCl treatments exerted stronger inhibitory effects than PLA-NPs alone, with the seed germination percentage and fresh weight reduced by an average of 52.7% and 6.6%, respectively. Notably, the inhibitory effects and integrated biomarker response (IBR) index of the PLA 500 + NaCl treatment were the highest. The presence of PLA-NPs in roots was confirmed using confocal laser scanning microscopy. GO enrichment analysis showed that pathways related to nutrient reservoir activity, oxidoreductase activity, hydrogen peroxide catabolic process, and hydrogen peroxide metabolic process were enriched under PLA-NP and PLA + NaCl treatments. KEGG analysis further indicated enrichment in phenylpropanoid biosynthesis, ABC transporters, and alpha-linolenic acid metabolism. The PLA-NP and PLA + NaCl treatments upregulated genes associated with oxidoreductase activity (Zm00001eb238800, Zm00001eb128620, and Zm00001eb020790). These findings suggest that synergistic toxicity of PLA-NPs and salinity stress in maize is primarily driven by the internalization of PLA-NPs and Na⁺ within maize roots, which negatively impacts maize seed germination and seedling growth by disrupting redox homeostasis and metabolic balance, thereby forcing plants to reallocate resources from growth toward oxidative stress defense. This study provides critical insights into the environmental risks of biodegradable nano-plastics in saline–alkali soil environments.