Current colorimetric methods for quantitative determination of seed viability (SV) with 2,3,5-triphenyl tetrazolium chloride (TTC) have been plagued by issues of being cumbersome and time-consuming during the experimental process, slow in extraction and staining, and exhibiting inconsistent results. In this work, we introduced a new approach that combines TTC-staining with high-temperature extraction using dimethyl sulfoxide (DMSO). The optimization of the germination stage, TTC-staining method, and 1,3,5-triphenylformazan (TTF) extraction method were meticulously carried out as follows: When the majority of wheat seeds had grown the radicle, and the length of radicles was approximately equal to the seed length (24 h-germination), 2 g germinating seeds were placed into a beaker (20 mL) containing 5 mL 10 g·L⁻¹ TTC solution. The seeds were stained with TTC in the dark at 25 °C for 1 h. Following the staining, 1 mL 1 mol·L⁻¹ H₂SO₄ was added to stop the reaction for 5 min. The H₂SO₄ solution was then removed, and the seeds were gently rinsed with deionized water. Subsequently, the TTF produced in the seeds was extracted directly with 5 mL DMSO solution at 55 °C for 1 h. The absorbance of the extract was measured at 483 nm, and the index of SV was calculated according to a predetermined TTC calibration curve and expressed by mg TTC·g⁻¹ (seed)·h⁻¹. The new method has been demonstrated to be rapid, stable, and highly sensitive, as evidenced by the accurate measurement of seed viability with different aging degrees.

Introduction: The soil bacteria promote the circulation conversion of lake nutrients and play an important role in maintaining the balance of the lake ecosystem. Few studies have investigated the association of seasonal variation in bacteria and environmental factors in inland freshwater lake wetlands. Nansi Lake is a large shallow freshwater lake in northern China. It is an important hub of the eastern route of the South-to-North Water Diversion Project.Methods: In this study, bacterial 16S rRNA genes were used to analyze the variation of soil bacterial community diversity in Nansi Lake Wetland and its influencing factors in different seasons.Results: It is showed that the phylum, family, and genus with the largest relative abundance in the soil of Nansi Lake Wetland are Proteobacteria, Nitrosomonadaceae, and MND1, respectively. There were significant seasonal differences in soil bacterial diversity in Nansi Lake Wetland, which was significantly higher in summer than in winter. Seasonal variation in environmental factors was significantly correlated with the variation in bacterial communities. Temperature and the content of available phosphorus may be the key factors influencing seasonal variation in bacterial diversity.Discussion: The results of this study further enhance our understanding of the relationship between bacterial community diversity and environmental factors in the lake wetland ecosystem, which can provide scientific data for the conservation of Nansi Lake Wetland.

Quercus variabilis is a key species for reforestation in East Asia, yet the mechanisms by which arbuscular mycorrhizal fungi (AMF) influence seedling growth and responses to soil-borne fungal challenge remain incompletely understood. This study combined physiological and metagenomic approaches to address this gap. Among seven rhizosphere fungal isolates, Fusarium tricinctum (F15) exerted the strongest growth-inhibitory effect on Q. variabilis seedlings and was therefore selected for subsequent experiments. Inoculation with the AMF Rhizophagus intraradices significantly promoted seedling growth (p < 0.05), increasing root length by 4.94% relative to the uninoculated control and increasing ground diameter and aboveground fresh weight by 28.57% and 117.07%, respectively, relative to F15-treated seedlings. AMF inoculation also significantly altered substrate nutrient status (p < 0.05), particularly nitrogen, phosphorus, and potassium, and enhanced the activity of antioxidant enzymes, including peroxidase and catalase (p < 0.05). Metagenomic analysis revealed that AMF significantly reshaped rhizosphere microbial community composition and bacterial α-diversity (p < 0.05), enriching beneficial taxa such as Mesorhizobium. Functional profiling showed differences in predicted microbial functional profiles between AMF-inoculated and F15-treated groups. Together, these results indicate that AMF enhances seedling growth and mitigates the negative effects associated with F15 challenge, potentially through altered substrate nutrient dynamics, enhanced antioxidant capacity, and modulation of the rhizosphere microbial community.