The Growth Expriment Of Main Submerged Macrophtes On Sediments In Poyang Lake

According to the results of the second scientific survey of Poyang Lake,the present situation of dominant species had changed and submerged macrophytes decreased significa ntly.In this paper,the experiments were carried out to simulate the growth of Vallisneria natans,Potomogeton malaianus and Hydrilla verticillata in sediments of Poyang Lake.We divided into nine groups(KN,KS,KS,MN,MC,MS,HN,HC,HS),from the two aspects of macrophytes growth and chlorophyll fluorescence kinetics to analyze their differences and common,for Poyang Lake submerged macrophytes restoration and reconstruction to provide a theoretical basis.(1)The results showed that the growth of submerged macrophytes was significantly different(P <0.05),and the three macrophytes had good growth in mudflat,which indicated that high nutrient storage was favorable for submerged.The results showed that the root activity was not directly related to the length of root length,and the root vigor was related to plant growth.From the growth index,the growth of algae was significantly better than that of the other two submerged macrophytes(P <0.05),Potomogeton malaianus is more suitable for the growth of hard soil in grassland,and the adaptability of Vallisneria is better than that of algae.(2)Submerged macrophytes can significantly improve water quality.In the course of the experiment,it was found that the plant growth could absorb a lot of chlorophyll a,nitrogen and phosphorus from the water body,increase the dissolved oxygen in the water,change the p H value and the redox potential of the water body,and increase the nutrient transfer capacity of the experimental system.(P <0.05),which was related to the more developed root system of the bitter grass.The developed root system played a key role in nutrient adsorption.In the sediment,the black algae decreased(P <0.05),and the content of TP decreased significantly(P <0.05),which was very good for the growth of nitrogen and leaves in the soil,and the phosphorus was deposited in the soil,The adsorption effect of the root system was significant.(3)The physiological activities of submerged submerged macrophytes were significantly affected.POD The results showed that the effects of stress on the physiological function of POD were destroyed,and the accumulation of free radicals and membrane lipid were increased.The results showed that the stress of POD was decreased,Which is consistent with the growth and decay of the growth index in the experimental stage,which indicates that the high nutrient substrate is a kind of adversity stress to the submerged macrophytes and can inhibit its growth.At the same time,the algae And Vallisner has a certain resistance to it,but with the growth of time and become weak.(4)In this study,it was found that the values of Fv/Fm in the experimental group were less than 0.7,indicating that the nutrient stress had been affected by the water stress in the water body,which indicated that the photosynthetic rate of the submerged plants had been declining.Fv/Fm was significantly higher than that of the other two submerged macrophytes(P <0.05),which indicated that the conversion efficiency of Haliotis discus hannai was higher in the center of PSII,Fv/Fm was significantly higher than that of grassland and sandy beach(P <0.05),which indicated that high nutrient soil had a favorable effect on plant growth,while good growth brought higher energy conversion efficiency.From the photosynthetic response curve,With the increase of PAR,the photosynthetic electron transport rate(ETR)increased with the increase of PAR,but the ascending rate decreased gradually.When the PAR values were 276 and 615,the light curve was significantly affected(P <0.05).The results showed that the photosynthetic efficiency was significantly higher than that of Vallisneria and Hydrilla verticillata(P <0.05),which indicated that the dominant species were resistant to glare,and that of Vallisneria had better resistance to low light.Based on the above results,1)the ability to adapt to the strongest and vigorous growth of the black algae,the growth of Potamogeton glauca is poor and the adaptability is weak.2)In terms of water purification capacity,Velvetia is better than the other two groups,Especially in the low nutrient soil growth;3)weak ability of light hard grass suitable for underwater growth,Malay eyes Sub-dishes and leaves of algae strong ability to withstand strong light,suitable for growth in the upper water level.