Interspecific root interaction enhances cadmium accumulation in Oryza sativa when intercropping with cadmium accumulator Artemisia argyi.

The contamination of arable land with heavy metals, such as Cd, is a serious concern worldwide. Intercropping with Cd accumulators can be used for efficient safe crop production and phytoremediation of Cd-contaminated soil. However, the effect of intercropping on Cd uptake by main crops and accumulators varies among plant combinations. Rhizosphere interaction may mediate Cd uptake by intercropped plants, but the mechanism is unclear. Thus, in the present study, we aimed to examine the effect of rhizosphere interaction on Cd uptake by intercropping rice (Oryza sativa L.) with mugwort (Artemisia argyi Levl. et Vant.) in Cd-contaminated paddy soil. We grew O. sativa and A. argyi in pots designed to allow different levels of interaction: complete root interaction (no barrier), partial root interaction (nylon mesh barrier), and no root interaction (plastic film barrier). Our results indicated that both complete and partial root interaction increased the shoot and root mass of A. argyi, but did not decrease the shoot, root, and grain mass of O. sativa. Interspecific root interaction significantly increased the Cd content in the shoots, roots, and grains of O. sativa and the shoots of A. argyi. Increased content of total organic acids in the rhizosphere, which increased the content of available Cd, was a possible mechanism of increased Cd uptake in both plants under interspecific root interaction. Our findings demonstrate that an intercropping system can extract more Cd from contaminated soil than a monocropping system of either A. argyi or O. sativa. However, the intercropping system did not facilitate safe crop production because it substantially increased grain Cd content in O. sativa.

Thymopentin-loaded phospholipid-based phase separation gel with long-lasting immunomodulatory effects: in vitro and in vivo studies.

Thymopentin (TP5) is an effective immunomodulatory agent for autoimmune disease that has been used clinically for decades. However, its application is greatly limited by its extremely short half-life in vivo, poor membrane permeability and extensive metabolism in gastrointestinal tract, resulting in repeated injection and poor patient compliance. In the present study, we developed a TP5-loaded, phospholipid-based phase separation gel (PPSG) to achieve sustained drug release profile and long-lasting therapeutic effects. We firstly demonstrated the physiochemical characteristics of PPSG before and after phase transition by examining the viscosity and morphology change caused by the phase transition. Moreover, the PPSG exerted a low cytotoxicity in L929 cells and HUVECs, suggesting the biocompatibility of PPSG. A month-long drug release profile of TP5 PPSG was observed both in vitro and in vivo, revealing its sustained and controlled drug release property. Most importantly, in cyclophosphamide-induced immunosuppressive rats, a single dose of TP5 PPSG (15 mg/kg, sc) injected could normalize their T-SOD levels and CD4+/CD8+ ratio; such an immunoregulatory effect was comparable to that produced by repeated injection of TP5 solution (0.6 mg/kg per day, sc) for 14 consecutive days. Thus, TP5 PPSG has a great potential for sustained delivery of TP5 in clinical use because of its simple manufacture process, good biocompatibility and long-lasting immunomodulatory efficacy, which could greatly improve patient compliance.

[Hydrochemical Characteristics and Its Origin of Surface Water and Groundwater in Dianbu River Basin].

Chaohu lake is a key water body for water pollution prevention and treatment in our country. However， it has been at a higher eutrophication level recently. Here， the surface water and groundwater in the Dianbu River Basin， a secondary tributary of Chaohu Lake， were taken as the research object. In order to test the hydrochemical composition and hydrogen and oxygen isotope values of different water bodies， 30 groups of surface water samples， 36 groups of groundwater samples， 16 groups of hydrogen and oxygen stable isotope samples， and 18 groups of groundwater hydrogen and oxygen stable isotope samples were collected in August 2021 （wet season）， November 2021 （normal season）， and February 2022 （dry season）. The seasonal and spatial variation characteristics were analyzed to explore the hydrochemical characteristics and formation mechanism of water bodies by means of mathematical statistics， Piper triangular diagram， Gibbs figures， and ion ratios. The following results were obtained： ① precipitation was the main source of surface water and groundwater in Dianbu River Basin， and the evaporation fractionation effect of surface water was more significant than that of groundwater. At different periods， the surface water was more enriched with stable isotopes of hydrogen and oxygen than groundwater. The stable isotopes of hydrogen and oxygen in water showed seasonal variation， relative enrichment in the wet season， and depletion in the dry season. ② Both surface water and groundwater in the Dianbu River Basin were weakly alkaline， and the concentration of ions in surface water was significantly lower than that in groundwater. Ca2+ and Na+ were the main cations in surface water， Ca2+ was the main cation in groundwater， and the dominant anion in all water was HCO3-. The hydrochemical typology of surface water was mainly HCO3·Cl-Na·Ca， and that of groundwater was mainly HCO3-Na·Ca. ③ The concentrations of the main hydrochemical indexes of surface water and groundwater showed certain seasonal and spatial differences. From the wet season to the dry season， the concentrations of TDS， K+， Na+， Ca2+， Mg2+， Cl-， and SO42- in surface water showed an increasing trend on the whole. The concentrations of Na+， Ca2+， and Mg2+ in groundwater showed little change but increased slightly， whereas the concentrations of Cl-， SO42-， and NO3- showed an increasing trend on the whole. The concentrations of Cl-， SO42-， and NO3- in the water showed relatively large seasonal fluctuations. From upstream to downstream， the concentrations of the main hydrochemical indexes in surface water first decreased and then increased， among which the concentration of NO3- increased the most. The concentrations of the main hydrochemical indexes of groundwater in the direction of runoff changed little overall， but the concentration in the discharge area was higher than that in the recharge area. ④ The formation of hydrochemical characteristics of the water was mainly controlled by water-rock interaction but was also influenced by human factors. The water-rock action was mainly the weathering dissolution of silicate rock， salt rock， and carbonate rock. Man-made pollutants such as sewage from a sewage treatment plant， domestic sewage， and feces had obviously changed the hydrochemical characteristics of the local water. ⑤ Compared with that in 2016， the concentration of NO3- in surface water showed a certain degree of reduction. The nitrogen pollution control work carried out by the local government had achieved certain results， but it was still necessary to strengthen the pollution prevention and control of sewage and feces in the downstream of the Dianbu River， some tributaries （such as the Dingguang River and Maqiao River）， and some residential areas.

Potential risk of eutrophication in the deepest lake of Southwest China: Insights from phosphorus enrichment in bottom water.

Large deep lakes in plateau regions provide crucial ecosystem services but are susceptible to eutrophication due to their long water residence time. To date, the water quality of deep lakes has not received as much attention as that of shallow lakes owing to logistical challenges. This study investigated the seasonal variation and vertical distribution of phosphorus and related environmental variables in a large deep lake in the Yunnan Plateau, China (Fuxian Lake). Generally, the concentrations of total phosphorus (TP, R2 = 0.862), total dissolved phosphorus (TDP, R2 = 0.922), and dissolved inorganic phosphorus (DIP, R2 = 0.889) exhibited a linear increase with the greater water depth, whereas the pH and dissolved oxygen (DO) showed decreasing trends. The TP, TDP, and DIP values were 0.012, 0.006, and 0.004 mg/L, respectively, in surface waters (0.5 m depth), and increased to 0.074, 0.065, and 0.062 mg/L, respectively, at 140.0 m depth. The averaged over ordering method demonstrated that DO and air temperature accounted for a higher proportion of the explained variance of TP, TDP, and DIP in the shallow water layer (0.5-20.0 m). In contrast, DO and pH accounted for a higher proportion of the explained variance of TP, TDP, and DIP in deeper water layers (40.0-150.0 m). As a warm monomictic lake, the higher observed phosphorus concentrations in deeper water and sediment potentially pose a risk of future eutrophication in the Fuxian Lake. Our findings demonstrate that more efficient technical and management measures should be taken to reduce the external phosphorus load to Fuxian Lake, so that the load to and from the sediment will decrease eventually.

[Preliminary survey on aquatic vegetations in Baiyangdian Lake].

A field survey was conducted on the species composition, community type, distribution pattern, and biomass of aquatic vegetations in the Baiyangdian Lake of Hebei Province. A total of 39 species were observed, including 16 emergent species, 14 submerged species, 6 floating-leaved species, and 3 floating species, belonging to 21 families and 32 genera. Compared with those about 15 years ago, 9 species were disappeared, community types were decreased from 16 to 13, and some predominant communities with large distribution area, such as Hydrilla verticillata and Najas major, were not found in the present survey. Meanwhile, the distribution pattern of aquatic vegetations was greatly changed. The biomass of aquatic vegetations decreased dramatically, compared to the survey in 1980. Human cultivation, random discharge of pollutants, and tremendous change of water level could be the main reasons for the degradation of aquatic vegetations and the great change of their distribution pattern in the Lake.