Study on Decomposition Characteristics of Key Indexes of Wetland Emergent Aquatic Plant

In order to reveal the decomposition characteristics of the emergent aquatic plants in wetland ecosystems, 2 typical wetland's emergent aquatic plants were selected under different habitats in Yunnan plateau wetlands: Scirpus tabernaemontani and Typha orientalis. The plant leaves litter samples from stages including the growth stage, withered stage, lodging stage, and the submerged stage as well as the bottom sediment samples were collected to analyze the changing dynamics of physical and chemical(elements and compounds) properties of the 2 plant litters in different stages of decomposition. The results showed that the contents of nitrogen, phosphorus, hemicellulose and ash of the 2 litters increased first and then decreased during the whole decomposition period, which was characterized by 'enrichment and release'. The iron content showed a tendency of increasing enrichment, which was characterized by 'enrichment'. The contents of potassium, lignin and cellulose showed a decreasing trend of release, which was characterized by 'release'. The dry matter content, ash content, phosphorus content and hemicellulose content of litters in the submerged stage were significantly different from litters in the early decomposition stage, indicating that the key properties of litters will change significantly after they touch the water body. During the whole decomposition period, the dry matter, specific leaf area, puncture strength, nitrogen, phosphorus, iron, potassium, lignin, cellulose and hemicellulose contents of the 2 litters showed the similar dynamic trends. It is implied that the dynamic change of these properties may be a general pattern involved in the decomposition of emergent aquatic plants.