Ecological adaptability and population growth tolerance characteristics of Carex cinerascens in response to water level changes in Poyang Lake, China.

Water level conditions are the key factors that affect the growth and distribution of wetland plants. Using Carex cinerascens (C. cinerascens) as the study species, we employ indoor simulations and field surveys. Our results show that C. cinerascens can adapt to rhythmic changes in the water level through different adaptation strategies. Compared to that of the control group, plant growth was better with a 0-0.4 cm/d water level rate, and plant growth was in the 42-56 cm range to that a 1.0-1.4 cm/d water level rate. Furthermore, it was observed that 0-0.4 cm/d was the most suitable growth rate, with 0.6-1.0 cm/d and 0-32 cm being the ideal plant tolerance ranges, and increasing to 1.0-1.4 cm/d and 32-56 cm exceeds the plant tolerance threshold. In the middle and late period of the experiment (25-45 d), the ecological characteristics of the plants changed significantly. For example, the root-to-shoot ratio of the plant in the stable water level reached 26.1. In our field observations, plant biomass can be influenced by a variety of environmental factors. The frequency of the species was the largest at an elevation of 15 m, and the growth status of the dominant and companion species of C. cinerascens was weakened with an increase in soil moisture content. The suitable water content for C. cinerascens growth was 27.6-57.3%, the distribution elevation was 12.54-16.59 m, and the optimum elevation was 13.56-15.54 m. The study is expected to provide a reference for wetland ecology research and wetland protection and restoration, a theoretical reference for the coordination of water resource development and utilization of Poyang Lake and ecological protection of important lakes and wetlands, and an important scientific basis for wetland hydrologic regulation, ecological restoration and biodiversity conservation.

Use of life cycle assessment and water quality analysis to evaluate the environmental impacts of the bioremediation of polluted water.

The lakes along the Yangtze River are important source of pollutants that ultimately flow from the river into the East China Sea. Bioremediation is a green technology used to treat polluted water in lakes along the Yangtze River. Life cycle assessment and a comprehensive water quality index are used to evaluate the potential environmental impacts of constructed wetlands (CWs), ecological floating beds (EFBs), and combined ecological floating beds (CEFBs). The results showed that the raw material acquisition, construction, and operation of the CWs, EFBs, and CEFBs accounted for 24.1%, 35.3%, and 40.6%, respectively, of the total environmental impact. The acquisition of raw materials to construct the bioremediation system accounted for 51.6% of the total environmental impact. Among the nine impact categories considered, the system's global warming potential was the largest. Among the three stages of the project (raw material acquisition, construction, and operation), construction had the largest impact on eutrophication (the eutrophic potential of the construction stage was the largest). Furthermore, the operation of the project reduced the human eco-toxicity potential. The evaluation of the water quality before and after implementing the project revealed that CEFBs purified the water more effectively than CWs and EFBs did, particularly with respect to the removal of the total phosphorus.

Asymmetric Total Synthesis of Propindilactone†G, Part†1: Initial Attempts towards the Synthesis of Schiartanes.

Our first-generation synthetic study towards the total synthesis of propindilactone G (1) and its analogues is reported. The key synthetic steps were an intramolecular Pauson-Khand reaction (PKR) and a vinylogous Mukaiyama reaction (VMAR). The stereoselective synthesis of the CDE ring moiety with an all-carbon quaternary center through a PKR was difficult, whilst a VMAR afforded a product with the opposite stereochemistry at the C20 position on the side chain. These results led us to redesign our synthetic strategy for the total synthesis of compound 1.