Spatiotemporal evolution of dissolved organic matter (DOM) and its response to environmental factors and human activities.

The South-to-North Water Diversion East Project (SNWDP-E) is an effective way to realize the optimal allocation of water resources in China. The North Dasha River (NDR) is the reverse recharge section that receives water from the Yufu River to the Wohushan Reservoir transfer project line in the SNWDP. However, the dissolved organic matter (DOM) evolution mechanism of seasonal water transfer projects on tributary waters has not been fully elucidated. In this paper, the NDR is the main object, and the changes in the composition and distribution of spectral characteristics during the winter water transfer period (WT) as well as during the summer non-water transfer period (NWT) are investigated by parallel factor analysis (PARAFAC). The results showed that the water connectivity caused by water transfer reduces the environmental heterogeneity of waters in the basin, as evidenced by the ammonia nitrogen (NH4+-N) and total phosphorus (TP) in the water body were significantly lower (p<0.05, p<0.01) during the water transfer period than the non-water transfer period. In addition, the fluorescence intensity of DOM was significantly lower in the WT than the NWT (p<0.05) and was mainly composed of humic substances generated from endogenous sources with high stability. While the NWT was disturbed by anthropogenic activities leading to significant differences in DOM composition in different functional areas. Based on the redundancy analysis (RDA) and multiple regression analysis, it was found that the evolution of the protein-like components is dominated by chemical oxygen demand (COD) and NH4+-N factors during the WT. While the NWT is mainly dominated by total nitrogen (TN) and TP factors for the evolution of the humic-like components. This study helps to elucidate the impact of water transfer projects on the trunk basin and contribute to the regulation and management of inter-basin water transfer projects.

The complete chloroplast genome of Sophora davidii (Fabaceae) and its phylogenetic implications.

Sophora davidii (Franch.) Pavol. is a deciduous or evergreen shrubs belonging to the genus Sophora, Fabaceae. The roots of S. davidii have been traditionally used as a medicinal herb in China to clear internal heat, relieve sore throat, and reduce swelling. Here we sequenced the whole genome of the chloroplast of S. davidii. The complete length of the chloroplast genome in S. davidii is 153,584 bp, containing a large single-copy region of 83,930 bp, a small single-copy region of 15,008 bp, and a pair of inverted repeats regions of 25,823 bp. The total guanine-cytosine (GC) percentage of the chloroplast genome was 36.7%. A total of 131 genes were annotated from the chloroplast genome of S. davidii, including 85 protein-coding genes, 8 rRNA genes and 38 tRNA genes. The phylogenetic analysis showed that S. davidii is closely related to the other three species of genus Sophora.