Effects of nanoscale zinc oxide treatment on growth, rhizosphere microbiota, and metabolism of Aconitum carmichaelii.

Trace elements play a crucial role in the growth and bioactive substance content of medicinal plants, but their utilization efficiency in soil is often low. In this study, soil and Aconitum carmichaelii samples were collected and measured from 22 different locations, followed by an analysis of the relationship between trace elements and the yield and alkaloid content of the plants. The results indicated a significant positive correlation between zinc, trace elements in the soil, and the yield and alkaloid content of A. carmichaelii. Subsequent treatment of A. carmichaelii with both bulk zinc oxide (ZnO) and zinc oxide nanoparticles (ZnO NPs) demonstrated that the use of ZnO NPs significantly enhanced plant growth and monoester-type alkaloid content. To elucidate the underlying mechanisms responsible for these effects, metabolomic analysis was performed, resulting in the identification of 38 differentially expressed metabolites in eight metabolic pathways between the two treatments. Additionally, significant differences were observed in the rhizosphere bacterial communities, with Bacteroidota and Actinobacteriota identified as valuable biomarkers for ZnO NP treatment. Covariation analysis further revealed significant correlations between specific microbial communities and metabolite expression levels. These findings provide compelling evidence that nanoscale zinc exhibits much higher utilization efficiency compared to traditional zinc fertilizer.

Antimicrobial activity, chemical composition and mechanism of action of Chinese chive (Allium tuberosum Rottler) extracts.

Chinese chive (Allium tuberosum Rottler) is a popular food from Allium species in East and Southeast Asia. Most Allium species possess characteristic aromas and have antimicrobial activity. In this study, the antimicrobial activities of root, leaf, and scape extracts of Chinese chive at different pH levels (3.0, 5.0, 7.0, 9.0, and 10.7) were compared. The most pronounced activity was produced by the scape extract, and the greatest activity was obtained at pH 5.0. HPLC and GC-MS analysis showed that the major active ingredient was 2-amino-5-methylbenzoic acid. The mechanism of action of Chinese chive scape extracts may involve the depression or disruption of cell membrane integrity, according to our results of the leakage of electrolytes and protein, as well as scanning electron microscopy and transmission electron microscopy observations.