长江口潮滩先锋植物藨草腐烂分解过程研究

Study on Putrefaction and Decomposition Process of Scirpus triqueter on the Changjiang Estuary Tidal Flat

以长江口崇明东滩湿地为研究区域，采集了先锋植物藨草（Scirpus triqueter）的地上茎和地下根部分，分别埋藏于高潮滩和堤内两处不同地点，研究了植物不同部位组织在腐烂分解过程中质量及其碳、氮元素含量的变化，分析了影响植物分解的主要因素。结果表明，藨草残体在为期391d的分解过程中质量损失了46％～66％，其中藨草茎分解速率大干藨草根的，高潮滩的大干堤内的；碳含量呈持续降低趋势，而氮含量则显著升高。植物体中初始营养盐水平和C／N比值的高低可能是导致藨草根、茎残体的分解速率存在差异的最主要因素。环境因素（如温度、湿度等）对藨草残体的腐烂分解有着十分重要的影响，温度升高、湿度增大，则加速微生物对植物碎屑的分解。由于受潮汐作用影响，高潮滩的植物埋藏环境比堤内的更潮湿，从而使得藨草在高潮滩的分解速率以及碳、氮元素含量的变化速率都明显高于堤内。

The Changjiang estuary Dongtan wetland was taken as the study area, the stems and roots of pioneer plant Scirpus triqueter were collected and buried in the high-tide flat and the beach within a dam to study the variations in mass, carbon and nitrogen contents in the putrefaction and decomposition process of Scirpus triqueter, and the main factors affecting the plant decomposition were analyzed. It is shown from the analysis results that after 391 days of plant decomposition, the masses of stem and root have lost 46 to 60 %, the decomposition rate of stem was higher than that of root, and the decomposition rate was higher in the high-tide flat than in the beach; the carbon content decreased constantly and the nitrogen content increased remarkably in the decomposition process. The initial nutrient levels and C/N ratios in the plant litter might be main factors affecting the decomposition rate. The environmental factors such as air temperature and humidity also affect the putrefaction and decomposition of plant litter, and the rise in air temperature and the increase in humidity will enhance the decomposition of plant litter by microbes. The plant burial environment in the high-tide flat is more humid than that in the beach within a dam due to the /tidal effect, so the decomposition rate and the carbon and nitrogen content variation rates of Scirpus triqueter litter in the high-tide flat are significantly higher than those in the beach with in a dam.