Study On The Biomass Forming Processes And Morphological Variance Of Phragmites Australis Population Of Songnen Plain Wetlands

Wetlands ecosystem, an important support system of life, is the indispensable materialbasis for human being's existence and development. Plant biomass occupies an importantplace in natural ecosystem. It is the material basis for studying the circulation of materials andenergy flow. In addition, it is the energy basis and nutrient resource for the running of thewhole ecosystem. To find the seasonal changes of population biomass, one can not only knowthe ecological characteristics and productive forces of population but also can further revealthe process of primary productivity of ecosystem, which means a great deal to themanagement and rational utilization of wetlands.Biomass of Phragmites australis population and morphology were studied in order toreveal productive regularity of P.australis wetlands, the process of productivity of wetlandsecosystem formation and the variation regularity of wetland plants' growth.The overground biomass of P. australis population increased gradually as time went onand reached the maximum in late August. Its seasonal dynamic curve was unimodal. Theseasonal dynamic curves of the biomass of stems, leaves, leaf sheaths, and spikes wereunimodal type, too.The vertical structure of stem biomass of P. australis population was typicalpyramid-shaped, and from the field surface, the biomass decreased gradually along with theheight. The vertical structures of leaf biomass of different growth periods were irregulardiamond-shaped. The vertical structures of leaf sheath biomass were not the same duringdifferent sampling periods. The vertical structure of spike biomass of growth anaphase wasirregular diamond-shaped. The vertical structure of the ratio (F/C) of biomass of assimilationorgans (F) to that of non-assimilating organs (C) increased gradually along with the height.The correlation analysis between biomass of P. australis population and soil moistureindicated that biomass of each sampling area decreased gradually along with the orientationof decreasing, that was, biomass of sampling area 1> biomass of sampling area 2> biomass ofsampling area 3> biomass of sampling area 4> biomass of sampling area 5> biomass ofsampling area 6. The changing regularities of height and biomass of P. australis populationwere excruciating uniform in seasonal process, and they were significant correlation. Thebiomass of P. australis population of each sampling area grew in function of power alongwith the increase of height. The analyses of coefficient of variation of six morphological characteristics showedthat the means of coefficient of variation of six morphological indexes (from large to small)were: leaf width>spike length >internode length>leaf length>number of internode>stemlength. Average coefficients of variation of morphological characteristics of each samplingarea (from large to small) were: sampling area 5> sampling area 6> sampling area 1>samplingarea 2> sampling area 4> sampling area 3. The multiple comparison among eachmorphological characteristics of different sampling areas showed that more morphologicalcharacteristics of different sampling areas were significant different, which indicated thatmorphosis was larger.