Study on dynamic characteristics between the biomass of Phragmites communis and water depth at Taihu wetland in Suzhou

With the rising of urban industrialization and elevation of living standard,the destruction of fresh water lake wetlands in city is becoming more and more serious.In this paper,Taihu wetland ecosystem in Suzhou was selected as target area and the Phragmites communis planted there was chosen as research object,the growth of Phragmites communis during a whole growing season was monitored to analyze the biomass seasonal distribution and the relationship between root-shoot ratio,height,density and water depth.The results as follows:(1) The aboveground biomass increased first and then decreased during the period from April 2009 to January 2010,the biomass reached the highest of(2 219.46±280.86) g/m2 in the late October,the maximum root-shoot ratio value(2.4) achieved simultaneously and minimum value of root-shoot ratio(1.5) was found in April;(2) Comparison for aboveground biomass among different observing spots showed that Seasonal Flooded Field ranked the first and Arid Field was the last,but Arid Field,for the underground biomass,was on the top;(3) For the root biomass underground,the maximum reached(5 113.41±313.86) g/m2 in the depth ranged 0-100 cm in late October,the mass ratio of root biomass underground 50-70 cm was(28.33±4.15)%,higher than that of root biomass in other depth;(4)The root-shoot ratio and density had a negative correlation with the water depth,but positive for the height.