Effect of fast restoration of aquatic vegetation on phytoplankton community after removal of purse seine culture in Huayanghe Lakes.

The disappearance of submerged aquatic vegetation caused by the use of purse seine in productive fishery has aroused the attention of the national government. In order to restore aquatic vegetation, the government has removed the seine nets on the Huayanghe Lake's surface. Here, fourteen cruises were conducted in the Huayanghe Lakes from 2016 to 2019 to study the response of water quality and phytoplankton communities to rapidly recovering aquatic vegetation. The results showed that the restoration of aquatic vegetation increased the Secchi depth (from 65.36 to 105.52 cm) and dissolved oxygen (from 8.98 to 12.17 mg/L), while the concentration of total nitrogen (from 0.98 to 0.53 mg/L), and total phosphorus (from 0.04 to 0.02 mg/L) decreased, resulting in a 35.3% and 11.6% reduction in the total phytoplankton density and chlorophyll ɑ, respectively. In addition, the restoration of aquatic vegetation significantly increased Shannon-Wiener diversity, Margalef richness indices by 51.6% and 40.1%. We also observed that phytoplankton density exhibited significant changes based on nonmetric multidimensional scaling analysis (NMDS). In Lake Huangda, the coverage of aquatic vegetation was as high as 80%. We also observed that after the restoration of aquatic vegetation, the proportion of cyanobacteria decreased significantly by 21%. Our study emphasizes that aquatic plants can alleviate eutrophication and increase the diversity of phytoplankton, thus providing guidance for the restoration and protection of water ecosystems in the lakes connected to the Yangtze River.

Ecological stoichiometric characteristics of Carbon (C), Nitrogen (N) and Phosphorus (P) in leaf, root, stem, and soil in four wetland plants communities in Shengjin Lake, China.

Ecological stoichiometric should be incorporated into management and nutrient impacted ecosystems dynamic to understand the status of ecosystems and ecological interaction. The present study focused on ecological stoichiometric characteristics of soil, and leaves, stems, and roots of different macrophytes after the banning of seine fishing in Shengjin Lake. For C, N, and P analysis from leaves, stems, roots, and soil to explore their stoichiometric ratio and deriving environmental forces, four dominant plant communities (Vallisneria natans, Zizania latifolia, Trapa natans and Carex schmidtii) were collected. The concentration of C, N, P and C: N: P ratio in leaves, stems, roots, and soil among the plant communities varied significantly. Along the depth gradient high C: N was measured in C.schmidtii soil (7.08±1.504) but not vary significantly (P >0.05). High C: P result was found in T.natans (81.14±43.88) and in V.natans soil (81.40±42.57) respectively with no significant difference (p>0.05). Besides, N: P ratio measured high in V. natans (13.7±4.05) and showed significant variation (P<0.05). High leaf C: N and N: P ratio was measured in C. schmidtii and V. natans respectively. Nevertheless, high leaf C: P ratio was measured in Z. latifolia. From the three studied organs, leaf C: N and N: P ratio showed high values compared to root and stems. The correlation analysis result showed that at 0-10cm depth soil organic carbon (SOC) correlated negatively with stem total phosphorus (STP), and root total nitrogen (RTN) (P<0.05) but positively strongly with leaf total phosphorus (LTP) and leaf total nitrogen (LTN) (P<0.01) respectively. Soil total nitrogen (STN) at 0-10cm strongly positively correlated with leaf total phosphorus (LTP) (P<0.01) and positively with RN: P and leaf total carbon (LTC) (P<0.05). Soil basic properties such as soil moisture content (SMC), bulky density (BD) and pH positively correlated with soil ecological stoichiometric characteristics. Redundancy analysis (RDA) result showed available nitrogen (AN), soil total nitrogen (STN), and available phosphorus (AP) were the potential determinants variables on plants stoichiometric characteristics.

Effects of Fructus ligustri lucidi on the growth, cell integrity, and metabolic activity of the Microcystis aeruginosa.

Agricultural waste has been used in the treatment of cyanobacterial bloom because of its environmental friendly and cost-efficient characteristics. In this work, the effects of Fructus ligustri lucidi (FLL) on the growth inhibition, physiological properties, algicidal property, and cell ultrastructure of Microcystis aeruginosa were investigated for the first time. The alga was efficiently inhibited by FLL at the dosages from 0.25 to 4.0 g L(-1), and the Chl-a fluorescence and metabolic activity of cells also declined gradually. During 25 days incubation time, the inhibition ratio of 0.25 g L(-1) dosage increased from 8 to 68 %, the percentage of intact cells decreased from 94.4 to 59.8 %, the inhibition ratio of 2.0 and 4.0 g L(-1) dosages was nearly 100 %, and the cell membranes were completely broken. The results of Chl-a, propidium iodide (PI) staining, fluorescein diacetate (FDA) staining, and transmission electron microscopy (TEM) assays were consistent with that of growth inhibition tests. The new medium test with the PI staining test suggested that FLL may act as an algicidal agent which can inhibit the growth of M. aeruginosa in the acute time. Consequently, FLL could be an excellent choice in the treatment of eutrophic water.

[Medicinal species of genus Polygonum s. lat. distributed in Anhui Province].

OBJECTIVE: To clarify the resource of medicinal plants of genus Polygonum s. lat. distributed in Anhui Province. METHOD: Conducting field investigation and consulting related specimens and data. RESULT AND CONCLUSION: The distribution, growing environment and medicinal use of 32 taxa have been clarified. A scientific basis for further study for these medicinal plants has been provided.