Cao Hui-cong

Ecotoxicity of Cadmium to Maize and Soybean Seedling in Black Soil

Ecotoxicity and bioavailability of cadmium (Cd) to the maize (Zea mays L.) and the soybean (Glycine max (L.) Merr.) were investigated by acute toxicity experiment in the laboratory with black soil. Ecotoxicity and bioavailability of Cd were quantified by calculating the median effective concentration (EC50) and bioaccumulation factor (BAF). The measurement endpoints used were seed germination and seedling growth (shoot and root). The results showed that concentrations of Cd in the soil had adverse effect on the growth of roots and shoots. Seed germination was not the sensitive indicator for the ecotoxicity of Cd in the soil, while the growth of roots was the most sensitive measurement endpoint. Absorbability and transport of Cd in plants depended on the test crop species and Cd concentrations in the soil. The maize retains more Cd in its roots, while the soybean transports more Cd to the shoots from roots.

Study on the eco-environmental water requirement for wetlands

Hydrology is the most important factor that determines the formation and maintenance of wetland ecosystem. Sufficient water quantity is necessary for the restoration of degraded wetlands. This study, based on the discussion about the type, functions and services of wetlands in Honghe National Nature Reserve, defines the components for eco-environmental water requirement and calculates the total eco-environmental water requirement for wetland ecosystem. The component for water requirement includes static water requirement and dynamic water requirement. The former refers to the water quantity required from the current surface level to the ideal surface water level, while the later includes water requirements for the plants, wildlife, recharge for groundwater and soil, respectively. The results indicate that the minimum water requirement is 16362.36×104m3 and the optimal water requirement is 25329.14×104m3, while the maximum requirement is 32115.70×104m3. Water requirement for wetland plants is the main component for the eco-environmental water requirement of wetland ecosystem.