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The results of phosphorus fractionation in the sediments from a contaminated river containing different aquatic plants, analyzed by solution 31P-NMR for Organic Phosphorus, showed that the concentration of Inorganic Phosphorus dominated in all species and Organic Phosphorus accounted for over 20% of Total Phosphorus. In general, orthophosphate was dominant in all the sampling sites. The proportion of Organic Phosphorus accounting for the Total Phosphorus in the sediments with different plant decreased in the following order: Paspalum distichum>Typha orientalis>Hydrilla verticillata. Phosphorus-accumulation ability of Paspalum distichum was obviously stronger than Typha orientalis and Hydrilla verticillata. The Organic Phosphorus was in aquatic plants dominated by humic-associated P (Hu-P), which converted to Inorganic Ohosphorus more significantly in submerged plants than in emerged plants. The sediment dominated by Paspalum distichum abundantly accumulated Organic Phosphorus in the orthophosphate monoester fraction. The degradation and mineralization of orthophosphate monoester was the important source of high Inorganic Phosphorus concentration and net primary productivity in Suoxu River. The Organic Phosphorus derived from Typha orientalis and Hydrilla verticillata was dramatically converted to Inorganic Phosphorus when the environmental factors varied.

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In this paper, l‐lysine (Lys), l‐glutamate (Glu), and l‐glutamine (Gln) grafted‐chitosan (CS) polymers (AA‐g‐CS) are prepared by the one‐pot method using EDC/NHS as coupling agents. The introduction of AA into the backbone structure of CS improves its solubility in the pH range of 6.0–7.0. Moreover, AA‐g‐CS/glycerophosphate hydrogel (AA‐g‐CS/GP hydrogel) prepared by physical cross‐linking has better thermosensitivity and can achieve the sol–gel transition in very short order. AA‐g‐CS/GP hydrogel has a dense three‐dimensional network structure, conducing to the loading of the hydrophobic drugs, and its pore size and pore wall are affected by Lys, Glu, and Gln. Berberine hydrochloride (BBH) is encapsulated within the three‐dimensional mesh of the hydrogel. And the addition of BBH has no significant effect on the structure of AA‐g‐CS/GP hydrogel. The optimal parameters for AA‐g‐CS/GP hydrogel loaded BBH (BBH@AA‐g‐CS/GP hydrogel) are the concentration of AA‐g‐CS is 4.5% and the volume ratio of AA‐g‐CS/GP is 1.4/0.6. It is shown that BBH@Lys‐g‐CS/GP hydrogel, BBH@Glu‐g‐CS/GP hydrogel, and BBH@Gln‐g‐CS/GP hydrogel have better‐sustained release effect. Moreover, the sustained release of BBH@Lys‐g‐CS/GP hydrogel is the best, and the cumulative release rate is about 56% in 24 h. Therefore, AA‐g‐CS/GP thermosensitive hydrogel is expected to be an excellent vehicle for sustained release of drugs.