闽江河口不同淹水环境下典型湿地植物-土壤系统全硫含量空间分布特征

Spatial Distributions of Total Sulfur Contents in Plant-soil Systems of the Typical Marshes with Different Flooding Regimes in the Min River Estuary

选择闽江河口鳝鱼滩湿地不同淹水环境下2条样带(A样带,远离主潮沟且退潮后无淹水;B样带,靠近主潮沟且退潮后有淹水)上的短叶茳芏、互花米草和扁穗沙草植被下的湿地为研究对象,探讨了湿地植物-土壤系统全硫(TS)含量的空间分布特征。结果表明,长期淹水环境在导致B样带同种植被类型下的湿地表层土壤的TS含量低于A样带的同时,也增强了不同植被类型下湿地之间0—40cm土层TS含量的水平变异性以及相同类型湿地土壤TS含量的垂直变异性。尽管长期淹水环境降低了B样带3种植被根的TS含量和累积系数,但增加了其地上器官及立枯体的TS含量和累积系数,并提高了其地上器官的硫分配比。对比研究表明,闽江河口3种湿地土壤和植物的TS含量在全国均处于较高水平,其值远高于三江平原淡水沼泽湿地、向海盐沼湿地以及华北海河流域湿地,但略低于南方红树林湿地。研究发现,淹水条件和土壤水分含量是导致A、B 2条样带相同类型湿地土壤TS含量差异的主导因素;淹水条件亦改变了湿地植物的硫分配格局,湿地植物可通过调整自身的硫吸收与累积状况来适应长期淹水环境。

To explore the spatial distribution of total sulfur（TS）contents in plant-soil system of tidal marshes in the Shanyutan of the Min River estuary,two transects（A transect,away from the main tidal channels with no flooding as the tide ebbs;B transect,near the main tidal channels with flooding as the tide ebbs）with different flooding regimes were laid and three typical plants（Cyperusmalaccensis,Spartinaalterniflora and Cyperuscompressus）of the marsh were studied in July 2015.Results showed that long-term flooding regimes caused same type of marsh top soil TS contents of B transect less than A transect,but also enhanced horizontal variability of 0-40 cm soil TS contents among different types marsh and vertical variability among the same ones.Although the long-term flooding regimes reduced the root TS contents and accumulation coefficient of three kinds of marsh plants in B transect,but increased above-ground organs and standing litter TS contents and accumulation coefficient,also increased the percentages of sulfur distribution in above-ground organs.Comparative studies had shown that the TS contents in soils and plants of the three typical marshes in the Min River estuary were in a high level across the country,and the values were much higher than those in the freshwater marshes of Sanjiang Plain,the salt marshes of Xianghai and the marshes in the Haihe River Basin,but slightly lower than those in mangrove swamps.The study found that floodingconditions and soil moisture were the dominant factors resulting in the differences of TS contents in soils of the same marsh located in A and B transects.Flooding conditions also altered the distribution patterns of TS content in different plants and plants could adjust their S absorption and accumulation traits to adapt to the flooding environment.