| Plant biomasses in Honghu wetland were investigated by a digital and rapid investigation method of the lake’s wetland using Landsat TM5data in the experiment. Season dynamic of plant biomasses in honghu wetland form2009.11to2010.9was investigated according to a reasonable field sampling route for the biomass.The results showed that in a emerging plant community, the trend of biomasses in is same in Zizania aquatica and Lotus:the biggest in ground biomass of Zizania aquatica and Lotus are1942.5g/m2and1784.3g/m2in Summer (September) and the lowest is in Spring;The underground biomass is larger than the ground biomass in the two emerging plants; the biggest underground biomass of Lotus in September is2.44times higher than that of the lowest in Spring,and the biggest biomass of Zizania aquatica in Summer is2.69times higher than that of the lowest in Spring.In the submerged plant community, the biggest biomass of Potamogeton maackianus and Myriophyllum spicatum are3486.8g/m2and428.7g/m2in November; the biggest biomass of C.demersum, V.spiralis and Hydrilla verticillata are874.4g/2m,181.4g/m2and9.8g/m2in September; the biggest biomass of Potamogeton crispus Linn is377.9g/m2in April. The biggest biomass of submerged plant community is4079.1g/m2(fresh weight, November). The total biomass of the emergent plant in November2009is12.58×107kg work out by the remote sensing technology.Wetland ecosystems have strong ability for carbon storage and fixation, and play important roles in the global carbon cycle. To understand carbon storage and fixation conditions of plant community in the typical wetland ecosystem of Honghu Lake, investigation was conducted on plant biomass and net primary productivity. In accordance with the theory of photosynthesis, carbon storage and fixation by plant in Honghu Lake wetland were estimated. Results show that carbon storage is at an average of0.33kg·m-2in shoots while the carbon storage in roots is0.65kg·m-2, which are about two times those of shoots,the carbon fixation is at an average of0.53kg·m-2·a-1. The carbon storage of submerged plant is different for different season, the carbon storage of Potamogeton maackianus in November is more than that of April, it is about1.33times than April, but the carbon storage of Potamogeton crispus Linn and Ceratophyllum demersum L in April is larger than November, its carbon storage are respectively2.1times and3times larger than November.The order of carbon storage in season average is:Potamogeton maackianus> Potamogeton crispus Linn＞Ceratophyllum demersum L. The submerged plant carbon fixation in April is stronger than November, the order of carbon fixation ablity is: Potamogeton crispus Linn＞Potamogeton maackianus＞Ceratophyllum demersum L.In order to study the nutrients element accumulation of wetland plant in Honghu Lake, element N, P, Kwas respectively measured using Kay type method molybdenum colorimetric method and flame photometric method. The other elements Cu Fe, Ca, Mg, and Zn were measured with atomic absorption method. The results show that the content of N, P, and K is varied in different plant species and different growth period in Honghu wetland. The order of the N, P and K content in plants is the submerged plant＞emergent plant, the order of the total accumulation of the three elemnts in plants is emergent plant> submerged plant. The differences of the nutrient element contents in the dominant species of in Honghu wetland were found among different spiecies and among different tissues of the same plant. The order of the N, P, K, Ca, Mg, Cu and Fe nutrition elements contents in Lotus is rhizome＞lamina＞leaf sheath＞flower. |
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