Physiological Response And Phytoremediation Remediation Potential Of Salvinia Natans And Salvinia Cuccullata To Cu²⁺

The effects of single factor Cu²⁺stress on the growth dynamics and physiological indexes of Salvinia natans and Salvinia cuccullata and the water quality polluted by Cu²⁺were studied by using Hoagland nutrient solution to culture seedlings of Salvinia natans and Salvinia cuccullata.The effects of different concentrations of EM Bacterial manure on physiological indexes of plants under Cu²⁺?CuSO₄?stress were studied.The results were as follows:1.Effects of different concentrations of Cu²⁺on vegetative growth of Salvinia natans and Salvinia cuccullata.The effect of copper-?Cu?stress on the growth indexes of Salvinia natans and Salvinia cuccullata was studied by liquid culture for 16 days.The results showed that high concentration of CuSO₄ could accelerate the death of Salvinia natans and Salvinia cuccullata,and the mortality was significantly correlated with the concentration of CuSO₄ and the treatment time.The death of Salvinia natans plants was mainly concentrated in the 6mg/L and 8mg/L CuSO₄ treatment groups.Most of the death occurred in the 8mg/L CuSO₄ treatment group on the 12th day.High concentration of CuSO₄ could significantly reduce the number of leaves,root length and axillary buds of Salvinia natans and Salvinia cuccullata,and inhibit the number of leaves and belly of Salvinia natans.The accumulation of duckweed biomass promoted the yellowing or rotting of leaves,which affected the healthy growth of two aquatic plants.However,low concentration of CuSO₄ could promote the root length and the dry weight of each organ of Salvinia natans.2.Effects of different concentrations of Cu²⁺on physiological Indexes of Salvinia natans and Salvinia cuccullata.The effects of copper?Cu?stress on physiological indexes of Salvinia cuccullata and Salvinia natans were studied by liquid culture for 16 days.The results showed that the chlorophyll content of Salvinia natans under CuSO₄ stress was lower than that of the control,but the content of chlorophyll was higher than that of the control as a whole,but the difference was not significant.Low concentration of CuSO₄ decreased the cell membrane permeability of the leaves of Salvinia natans and Salvinia cuccullata,while the membrane permeability increased and the injury increased under the high concentration of CuSO₄ in the roots of Salvinia natans.The POD activity of SOD,leaves and the CAT activity of roots were significantly increased by low concentration of CuSO₄,and the CuSO₄ activity was increased in the roots of Salvinia natans.The SOD,POD and CAT activity of leaves decreased significantly at higher concentration.The activities of SOD,POD and CAT were in a dynamic equilibrium state,and could play a self-regulating role in injury,but the activity of POD could not be regulated normally when the concentration of CuSO₄ was high.With the increase of CuSO₄concentration,the MDA content of Salvinia cuccullata and Salvinia natans increased with the increase of low concentration of CuSO₄,and the content of MDA of Salvinia cuccullata and Salvinia natans increased.The results showed that Salvinia cuccullata and Salvinia natans had certain tolerance under low concentration of CuSO₄ stress,and could be Cu²⁺.The remediation of polluted environment provides a certain theoretical reference.3.Effects of different EM Bio-fertilizer concentrations on physiological Indexes of Salvinia natans and Salvinia cuccullata under Cu²⁺stress.The effects of different concentrations of EM bio-fertilizer on physiological characteristics of Salvinia cuccullata and Salvinia natans under Cu²⁺stress were studied in solution culture.The results showed that the chlorophyll content of Salvinia cuccullata and Salvinia natans leaf increased as a whole,and reached the highest level when treated with 1g/L?CuL?.EM bio-fertilizer decreased the permeability of cell membrane of Salvinia cuccullata,but had no obvious effect on the electrical conductivity of Salvinia natans.Under the action of EM biological fertilizer,the activities of SOD,POD and CAT both increased,but the effect was not significant.Low concentration of EM increased the antioxidant stress ability of the two plants.The content of MDA was increased by biological fertilizer,and the content of MDA was decreased by high concentration of EM.4.Analysis of the physical and chemical properties of the culture medium after planting Salvinia natans and Salvinia cuccullata.The effects of single cultivation of two aquatic plants Salvinia cuccullata and Salvinia natans on water quality indexes polluted by different concentrations of CuSO₄were studied.The results showed that the pH value of the water quality of Salvinia natans was alkaline,but the pH value of the water quality of cultivated Salvinia cuccullata was more acidic than that of the control.The water conductivity of Salvinia natans was lower than that of the control,and decreased with the increase of the concentration of CuSO₄.The conductivity of the water was higher than that of the control.The cultivation of Salvinia cuccullata;and Salvinia natans can increase the dissolved oxygen and biological oxygen demand of Cu polluted water body,and the redox potential of Cu²⁺polluted water body can be decreased more significantly by planting Salvinia natans,and the high concentration of Cu²⁺is more significant than that of Salvinia cuccullata.It is beneficial to the absorption of Cu,Ca and Zn by two aquatic plants,but it was not conducive to the absorption of Cd by the two species.