Study On The Growth Principle And Ecological Function Of The Phragmites Australis And Phalaris Arundinacea Populations In The Mount Beigu Wetland

The Mount Beigu wetland ecosystem has retrogressed seriously, because the wetland was destroyed and used irrationally by people. Phragmites australis and Phalaris arundinacea populations are dominant populations in the wetland, which play important role in the Mount Beigu wetland ecosystem. The growth principle and ecological function of the Phragmites australis and Phalaris arundinacea populations were studied in this paper, the objective is to provide the theoretic supervises for the wetland human-induced restoration. The major results are as follows:(1) According to the results of investigating and analyzing plenty of sample plots and combing the conclusions of the succession process in the Mount Beigu wetland. The author partitions the phenophase of the Phragmites australis and Phalaris arundinacea populations, and analyses the density and the shoot length dynamics of the Phragmites australis and Phalaris arundinacea, It shows that the variation of the shoot length dynamics is near to the Logistic curve, and also discovered that the growth principle of those populations adapted to the environment for a long time.(2) After analyzing the above ground and under ground biomass seasonal dynamics, the above-ground biomass, shoot length and base stem of the Phragmites australis were analysed with SPSS software, the result is that the shoot length is more important than base stem in redounding to above-ground biomass. Compared with other organs, the stems and leaves of the Phragmites australis and Phalaris arundinacea offer more biomass.(3) The photosynthesis and transpiration diurnal changes of the Phragmites australis and Phalaris arundinacea in different growth stage and under different weather were studied. The Phalaris arundinacea daily course of net photosynthesis showed double peaked in the early growing season and fast growing season, and there was a clear depression of Pn at noon; The photosynthesis diurnal change trend of the Phragmites australis were the same as the Phalaris arundinacea. But its daily course of net photosynthesis was single peaked in the late growing season. The average of Pn and Tr were clearly higher in fast growing season than that in early growing season and late growing season. The net photosynthesis and transpiration in overcast day is clearly lower than in fine day , PAR is the most important factor.(4) The result was that different eco- physiological factors effects Pn in different situation. Compared Pn, biomass of the Phragmites australis and Phalaris arundinacea...