First detected in environmental matrices in the early 2010s, UV-328 has aroused widespread concern due to its toxic risks to terrestrial vascular plants. However, its impacts on photosynthetic performance of bryophytes remain unclear. In this study, we exposed the moss Niphotrichum japonicum to a range of UV-328 concentrations and examined its morphological changes, oxidative stress, photosynthetic pigments, chlorophyll fluorescence kinetics, and energy allocation. Our results show that UV-328 caused dose-dependent leaf yellowing, surface shrinkage, and papillae collapse. It degraded photosynthetic pigments, disrupted chlorophyll a/b balance, and induced excess reactive oxygen accumulation. Chlorophyll fluorescence data indicated that UV-328 noticeably lowered Fv/Fm, Y(II), and qP. OJIP kinetics confirmed multi-target damage to the photosynthetic chain, including disruption of the oxygen evolving complex, decline of PSII energetic grouping, blockage of electron transfer from QA- to QB, inhibition of plastoquinone pool turnover, and PSI terminal electron transport. Energy flux parameters pointed to fewer active PSII reaction centers and a higher light-harvesting load on each remaining center, which uncoupled light capture from electron transfer. The concentration that caused clear photosynthetic damage fell between 100 and 150 μM. In conclusion, UV-328 impacts moss photosynthesis through oxidative stress, structural damage, blocked electron transport, and energy imbalance.
The comparative UHPLC-MS/MS analysis of the underground and aerial parts of Primula veris subsp. columnae (Ten.) Lȕdi revealed a diverse range of secondary metabolites, including flavonoids and phenolic compounds and their glycosides, bisbibenzyl compounds and triterpene saponins. Phytochemical study of the aerial parts led to the isolation of 13 surface flavonoids and 6 flavonoid glycosides, of which 8,2'-dimethoxy-5-hydroxyflavone and 8,3'-dimethoxy-5-hydroxyflavone are new natural compounds. From the underground parts, a new triterpene saponin, primulasaponin VI, was isolated together with the known primulasaponins I, III and V; priverosaponin B 22-acetate; primulaverin; primverin; gaultherin; and 3-methoxy-4-primeverosylacetophenone. The structures of the new compounds were elucidated by NMR and HR-ESI-MS. The acetone extract obtained from the aerial parts and methanol extracts obtained from both aerial and underground parts were evaluated for their antibiofilm activity against Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus. The methanol extract obtained from underground parts possessed the strongest overall antibiofilm activity, particularly against E. coli and S. aureus. While the acetone extract inhibited the biofilm formation by E. coli and S. aureus, it promoted biofilm formation by P. aeruginosa. All tested extracts exhibited low cytotoxicity toward human keratinocytes and melanoma cells.
Developing effective rhizobial inoculants for high-latitude soybean production requires strains that are both well-adapted to local soil conditions and capable of sustaining symbiotic nitrogen fixation under abiotic stress. In this study, 66 indigenous rhizobial strains isolated from four ecological regions of Heilongjiang Province, China, i.e., the Songnen Plain, Sanjiang Plain, Northwest Arid Sandy Region, and Daxing'anling-Xiaoxing'anling mountainous area, were characterized for phenotypic diversity, abiotic stress tolerance, symbiotic nitrogen fixation capacity, and plant growth-promoting (PGPR) traits. Carbon and nitrogen source utilization, physiological and biochemical properties, and tolerance to salinity, pH extremes, temperature, and drought were assessed and analyzed by hierarchical cluster analysis. The strains showed habitat-associated phenotypic differentiation, with stress-tolerance traits accounting for the greatest proportion of variation. Isolates from the Northwest Arid Sandy Region displayed the broadest stress tolerance, while Sanjiang Plain isolates showed more conservative phenotypic profiles. Eight representative strains were subsequently evaluated for symbiotic performance and PGPR activity. Nodule dry weight, nitrogenase activity, and total plant nitrogen content were strongly intercorrelated and appeared more reliable indicators of nitrogen-fixation efficiency than nodule number alone. Songnen Plain strains SN1 and SN8 showed the highest symbiotic performance, while Northwest Arid Sandy Region strain FS1 exhibited the greatest ACC deaminase activity. A two-dimensional ranking framework integrating symbiotic and non-symbiotic traits ordered the strains as SN1 > SN8 > SJ1 > SJ11 > DX5 > DX1 > FS7 > FS1, identifying SN1 and SN8 as the most promising candidates requiring field validation for inoculant applications. These findings suggest that multi-trait evaluation frameworks may offer a practical and reproducible approach to screening indigenous rhizobia for region-specific biofertilizer applications in cold-region soybean agriculture.
Herbaceous and subshrub species of the genus Ajuga are recognized as valuable sources of bioactive metabolites with diverse pharmacological properties. This study comparatively evaluated the phytochemical composition and the in vitro biological activities of Ajuga chamaepitys, A. genevensis, A. laxmannii, and A. reptans collected from different localities in Serbia. UHPLC-MS/MS profiling identified p-hydroxybenzoic acid and ferulic acid as the predominant phenolic compounds. A. reptans exhibited the highest total phenolic content (120.52 mg GAE/g dw), along with the strongest antioxidant activity in DPPH, ABTS, β-carotene bleaching, and FRAP assays, as well as the highest antibacterial activity. A. laxmannii contained the highest flavonoid content (48.95 mg QuE/g dw) and showed the strongest antifungal activity, whereas A. genevensis demonstrated the most potent tyrosinase inhibitory activity. Notably, A. genevensis extracts exhibited pronounced anti-pyocyanin activity, approximately twofold stronger than ampicillin. These findings demonstrate significant species- and locality-dependent variation in the phytochemical composition and biological activity and identify Serbian Ajuga species as promising natural sources of antioxidant, antimicrobial, and antivirulence compounds with potential pharmaceutical and food applications.
Accurate identification and effective prediction of the maize tasseling stage are of great significance for guiding precision field management and ensuring stable crop yields. Conventional manual observation methods suffer from high labor intensity, poor timeliness, and strong subjectivity. In this study, based on an unmanned aerial vehicle (UAV) remote sensing platform, LiDAR point cloud data and RGB imagery were simultaneously acquired to construct digital surface models (DSMs) and digital terrain models (DTMs). Multi-dimensional statistical features were extracted to establish a high-precision plant height estimation method applicable to the entire growth cycle of maize. On this basis, the Logistic growth curve function was introduced to fit the dynamic changes in plant height, enabling the identification and early prediction of the maize tasseling stage based on the plant height growth curve. The research results indicate the following: (1) For maize plant height estimation, the LiDAR sensor outperforms RGB. The optimal accuracy is achieved by combining the 99th percentile of DSM with the minimum DTM, yielding a root mean square error (RMSE) of 0.17 m. (2) Based on the high-accuracy plant height time series, the point of inflection (POI) achieves the highest accuracy in tasseling stage identification, with an RMSE of 2.586 d under the reconstructed time series. (3) Prediction accuracy of the tasseling stage improves with increasing plant height threshold, and optimal performance is observed when the threshold is ≥1.6 m with a growth rate between 0.11 and 0.13. This study establishes a technical framework of "time-series perception-dynamic simulation-feature identification-early prediction", providing a scientific basis for automated monitoring and precision management of the maize tasseling stage. It holds significant theoretical and practical value for the advancement of smart agriculture and crop phenotyping research.
