Study On Microbial Diversity And Soil Enzyme Activity In Panjin Wetland

Wetland ecosystem plays an important role in maintaining biodiversity and regional climate.The degradation of wetland ecosystem not only affects the wetland area and biodiversity,but also greatly affects the climate environment and ecological balance of the whole region.In this experiment,the laboratory culture method and moleccular biology method of microorganism were used to study and analyze the seasonal changes of microorganism quantity,some dominant populations and soil enzyme activity in different soil depths under the control of the dominant species reed,Suaeda salsa and blank plants in Panjin wetland.the largest coastal reed marsh wetland in China.The main results are as follows:(1)In different seasons,Proteobacteria is the dominant flora in Phragmites communis,followed by Actinomycetes.Proteobacteria under Suaeda salsa is the most dominant flora,and actinomycetes is the second dominant flora.The flora with higher relative abundance is similar to reed.In the blank control,Proteobacteria is the most dominant flora,and the second dominant bacterium is Actinomycete.In general,the diversity of soil bacteria in different seasons and depths under Suaeda salsa was more than that of blank control and reed sample points in that season and depth.(2)The number of bacteria under the three planting covers is higher in April than in other February,which may be related to the changes of soil temperature and nutrition in different seasons.In the soil without plants,the number of bacteria decreased with the increase of soil depth.and the number in April was higher than that in other months.The change trend of actinomycetes and bacteria under reed is consistent,and the content in July is obviously higher than that in other months.With the increase of soil depth.The number of actinomycetes increased first and then decreased.The number of fungi in autumn was higher than that in other two seasons,and the number of fungi in April was slightly higher than that in July.(3)Phosphatase activity change:Phragmites communis in October is basically higher than that in the other two months,which is similar to the soil change without plant growth.The activity of Suaeda salsa in July and October is basically similar,which is 4 times as high as that in April,indicating that the soil has different transformation ability to organophosphorus under different plants.Glucosidase activity:reed soil and non-plant growing soil are basically undetectable or very low in April and October,and enzyme activity decreases with increasing soil depth in July,which means that more microorganisms use cellulose as nutrient in topsoil.Polyphenol oxidase activity:all measured soil depths of reed,Suaeda salsa and non-plant soil are higher in April than in July and higher than in October,but the change trend of activity is different.Reed first increases and then decreases with soil depth,while Suaeda salsa shows a trend of first decreasing and then increasing.Catalase activity:The activity of catalase in reed soil has not changed significantly in three months.The activity of this enzyme in Suaeda salsa area was greater in October than in April and greater than in July.The activity of this enzyme is the highest in April in non-plant soil.Catalase activity characterizes the humus intensity of soil and the accumulation degree of organic matter.Cellobiose enzyme activity:the enzyme activity in reed soil was basically zero in October,and gradually decreased to zero in April and July with the increase of soil depth.The enzyme activity was detected in only one spot of Suaeda salsa soil and plant-free soil.This indicates that the microbial metabolic cellulose activity is relatively low in the soil of this area.