Study On The Physiological And Ecological Effects Of Silicate Minerals On Submerged Macrophytesthe

The restoration of submerged macrophytes is an important step in reconstruction lake ecosystem.The sediment property is one of the key factors for the growth of submerged macrophytes.Traditional methods of sediment modification,such as medication and dredging are easy to cause secondary pollution to the environment and have a series of potential safety hazards.Therefore,it is important to explore a green pollution-free environment-friendly sediment modification method.The use of medical stone for controlling phosphorus in lake sediments has been proven^[76],but the influence of medical stone on submerged plants remains to be investigated.Therefore,this study designed three parts of experiments.First,lake sediment and medical stone were Laying at the bottom of the glass jar,then planting submerged plants;Second,planting submerged plants in outdoor PVC barrels;Third,setting the germination experiment of Vallisneria natans seeds in the light incubator with the medical stone as the substrate,and counting the germination rate.The influence of medical stone on submerged plants was discussed through the above experiments.It provides reference data and theoretical basis for applying of inorganic silicate minerals medical stone in lake sediment improvement engineering application.The research results are as follows:（1）The experimental results of the glass-cell microcosm showed that the medical stone can significantly promote the growth of the submerged plant compared with the lake mud group,.The height of the plant and biomass per plant with 1 cm thick medical stone are better than that of the lake mud group（P<0.05）.The plant height and biomass per plant of the modified medical stone group were higher than those of the medical stone group（P<0.05）.The photosynthetic pigments,root activity,malondialdehyde and oxidase activity of the two plants in the medical stone group were better than those in the lake mud group.It has been found that the medical stone are rich in macro and trace elements needed for plant growth,which can significantly promote the growth of submerged plants.It can be seen that the inorganic silicate minerals medical stone is beneficial to the growth of submerged plants,and can be further applied as a substrate improving material to the lake ecological restoration project.（2）The results of PVC barrel test showed that the leaf number and width of Vallisneria natans in 1 cm modified medical stone group were significantly higher than those in lake mud group（P<0.05）,and the biomass,height,root length and root activity of Vallisneria natans in 1 cm and 3 cm groups were higher than those in other groups.The highest biomass of Vallisneria natans in MM1 group was 159.7 cm,which was 129.8%of lake mud group,and the highest biomass in MM1 group was156.8%of lake mud group.The results of the Hydrilla verticillata group were similar to those of the Vallisneria natans.The plant height of the 1 cm modified medical stonne group was higher than that of the other groups,and the highest was 105.7 cm,which was 145.3%of mud group.The leaf spacing,biomass and root length of Vallisneria natans in MM1 group were better than those in other groups.The photosynthetic pigments and root activity of the two plants in MM1 group were better than those in other groups.The activities of oxidase,malondialdehyde and soluble protein all reflected that medical stone could delay the senescence process of plants,but the effect of modification of medical stone on plant growth was not significant.In addition,the growth of plants in 7 cm group was inferior to that in lake mud group to a certain extent,the excessive thickness of medical stone paving may inhibit the growth of plants.（3）The results of the germination experiment of Vallisneria natans seeds showed that the germination of the Vallisneria natans seeds in the medical stone powder group was significantly lower than that in the other groups.This possible reason may be that the physical structure of medical stone was changesd and the water absorption capacity was deteriorated after grinding into a powder,resulting in plant seeds germination affected.But the medical stone powder:lake mud=1:3 and medical stone particles:lake mud=1:3 group promoted the germination of the Vallisneria natans seeds to some extent,which may be because the dissolved trace elements of medical stone,promoted seed germination to a certain extent,and the gas substance exchange efficiency with the outside is higher for the better permeability of the medical particles,thus the germination of theVallisneria natans was promoted to some extent.