Search

The spatial and temporal dynamics of crop canopy structure are influenced by cultivar, environment, and crop management practices. However, continuous and automatic monitoring of crop canopy structure is still challenging. A three-dimensional (3D) time-series phenotyping study of maize canopy was conducted using a rail-driven high-throughput plant phenotyping platform (HTPPP) in field conditions. An adaptive sliding window segmentation algorithm was proposed to obtain plots and rows from canopy point clouds. Maximum height (Hmax), mean height (Hmean), and canopy cover (CC) of each plot were extracted, and quantification of plot canopy height uniformity (CHU) and marginal effect (MEH) was achieved. The results showed that the average mIoU, mP, mR, and mF1 of canopy–plot segmentation were 0.8118, 0.9587, 0.9969, and 0.9771, respectively, and the average mIoU, mP, mR, and mF1 of plot–row segmentation were 0.7566, 0.8764, 0.9292, and 0.8974, respectively. The average RMSE of plant height across the 10 growth stages was 0.08 m. The extracted time-series phenotypes show that CHU tended to vary from uniformity to nonuniformity and continued to fluctuate during the whole growth stages, and the MEH of the canopy tended to increase negatively over time. This study provides automated and practical means for 3D time-series phenotype monitoring of plant canopies with the HTPPP.

The binary structure of the floodplain in the reaches of the Yangtze River is obvious and has unique hydrogeological features. In this paper, the hydrogeological survey of the floodplain area is carried out. It is found that the permeability coefficient of the floodplain area is gradually increasing from top to down, and is larger than that of the similar layer in other areas. The horizontal and vertical permeability coefficients are not much different. This hydrological survey results of this paper provide a certain reference for similar dewatering projects in the floodplain area of the lower reaches of the Yangtze River.

Rationale: The Maillard reaction plays an important role in food, physiology and traditional Chinese medicine, and its primary reaction products are formed through Amadori rearrangement by reducing sugars and amino acids. The analysis of the characteristic fragmentation and of the glycosidic bond configuration of Amadori compounds will promote their fast discovery and identification by mass spectrometry. Methods: Four Amadori compounds that reduce disaccharides and proline/tryptophan were used to investigate the fragmentation mechanisms via tandem mass spectrometry (MS/MS) with different alkali metal ion adducts. Cu2+could be used to distinguish glycosidic bond configurations of the reducing disaccharides in the full-scan mass spectra. Quantum calculations were also conducted for a single Amadori compound with Cu2+ for analysis of the most optimized configurations and binding energies of metal complexes. Results: MS/MS analysis of Amadori-alkali metal complexes revealed that the radius of the alkali metal ions had profound effects on the degree of fragmentation of such compounds, among which lithium-cationized ions produced the most extensive fragmentation. Amadori compounds with different glycosidic bonds formed differently proportioned metal complexes with Cu2+, and the complexity of the copper complexes containing tryptophan moieties was higher than that of those containing proline moieties in the mass spectra. Quantum calculations showed that Amadori compounds with β-configurations can form more binding sites with Cu2+than those with α-configurations, thus making the metal complex with a single ligand more stable. In addition, the chelation of tryptophan with copper ions increased the coordination binding energy, which showed that α-configured Amadori compounds were readily able to form multi-ligand copper complexes. Conclusions: Metal-ion-assisted analysis provides crucial information for structural and anomeric analysis of Amadori compounds by electrospray ionization mass spectrometry. Elucidation of binding sites and binding energies by quantum calculations has significantly improved the knowledge of metal complexes in the gas phase and provides background information for determining the glycosidic configuration of Amadori isomers. [ABSTRACT FROM AUTHOR]