长江口潮滩湿地土壤酶活性的陆向变化以及与环境因子的相关性

研究了长江口崇明东滩潮滩湿地表层沉积物的土壤酶活性和环境因子沿高程的陆向变化及其它们之间的相关性。结果表明,在潮滩湿地表层沉积物中的全磷(TP)、全氮(TN)和有机质(OM)的含量,随着高程的增加,其含量呈上升趋势,而沉积物平均粒径(AGS)和溶解无机磷(DIP)含量逐渐降低。崇明东滩表层沉积物中碱性磷酸酶活性沿高程梯度有增加的趋势,与沉积物平均粒径和溶解无机磷含量呈极显著负相关(p<0.01),与有机质、总氮、总磷含量呈显著正相关(p<0.05),反映出碱性磷酸酶活性受底物和产物并存机制的诱导或抑制。过氧化氢酶活性随高程也有逐渐增大的趋势,其活性与有机质、总氮、总磷呈显著正相关与溶解无机磷和沉积物平均粒径呈负相关(p<0.05),充分反映了随着演替的发展,沉积物的肥力逐渐增高的特点,也反映了沿高程梯度沉积物生物氧化作用逐渐增强。转化酶活性从藻类盐渍带到芦苇(Phragmites australis)带变化并不明显,在海三棱藨草(Scirpus mariqueter)带略高。蛋白酶活性从藻类盐渍带到芦苇带有降低的趋势,蛋白酶活性的高低更决定于有机质中蛋白质的含量而与有机质总量无关,说明蛋白酶可能主要由硅藻产生。

The landward changes of soil enzyme activities in a tidal flat wetland of the Yangtze River estuary and correlations with physico-chemical factors

The landward changes of soil enzyme activities and physico-chemical properties of the surface sediments in the east end of Chongming Island,in the Yangtze river estuary,were studied.Along the elevation gradient or succession sequence,the contents of total phosphorus(TP),total nitrogen(TN)and organic matter(OM)of sediment increased,but the average grain size(AGS)and dissolved inorganic phosphorus(DIP)decreased.The activity of alkaline phosphatase increased gradually along the elevation gradient,and was positively correlated with the values of TP,TN and OM(p<0.05),but negatively to AGS and DIP(p<0.01).Alkaline phosphatase activity was correlated with a mechanism of substrate inductivity and product inhibition.Catalase activity had the similar trend of gradual elevation increase and enhanced the fertility of the soil and oxidative process of OM in the sediment.From the succession zones,bare flat to bulrush(Scirpus mariqueter)to reed(Phragmites australis),the activity of sucrase changed only insignificantly but the bulrush zone had a higher activity than others.The activity of proteinase decreased from bare flat to reed zone and the activity was negatively correlated with OM and TN(p<0.05),but positively with DIP(p<0.05).Through the succession zones a decrease in number of diatoms resulted in a decline in the concentration of protein,which influences the proteinase activity,suggesting that the proteinase in the sediment was produced by diatom.