常见水生植物对氮磷营养盐的利用和蓄积

Utilization and Accumulation of Nitrogen and Phosphorus Nutrients by Common Aquatic Plants

以风车草(Cyperus involucratus Rottboll)、菖蒲(Acorus calamus)、美人蕉(Canna indica)、凤眼莲(Eichhornia crassipes)、苦草(Vallisneria natans)和金鱼藻(Ceratophyllum demersum)6种水生植物为研究对象,采用常规耗竭法分析其养分吸收动力学特征,探究水生植物对水体氮磷的利用和蓄积能力,同时还探讨了硫累积及水体pH对水生植物吸收氮磷的影响。结果表明:挺水植物对氮磷营养盐的利用和蓄积能力高于其他水生植物;其中美人蕉对水体总氮(total nitrogen,TN)和总磷(total phosphorus,TP)的蓄积量最多,达到40.95 mg和5.83 mg,菖蒲的最大吸收速率(I_(max))比其他水生植物更高,分别为1.428 mg·g^(-1)·d^(-1)和0.313 mg·g^(-1)·d^(-1);挺水植物对水体TN和TP去除率均超过85%,贡献率达到80%。硫的累积不利于水生植物对氮磷的蓄积和利用;美人蕉对硫的累积量最少,其对氮磷的去除率在6种植物中最高,达到92.29%和86.24%。水生植物在生长过程中会改变水体的pH,而水体pH又会反过来影响水生植物对氮磷的吸收和蓄积。综上可知,挺水植物具有较好氮磷利用与蓄积能力,培养环境中过多的硫及过低的pH均会降低水生植物对氮磷的利用和蓄积。

Six species of aquatic plants,namely,Cyperus involucratus Rottboll,Acorus calamus,Canna indica,as well as Eichhornia crassipes,Vallisneria natans and Ceratophyllum demersum were studied here.Their nutrient uptake kinetics were determined by the conventional depletion method,which was used to explore their capacity to utilize and accumulate nitrogen and phosphorus from water.Additionally,we discussed the impact of sulfur accumulation and water pH on the uptake of nitrogen and phosphorus by the above-mentioned aquatic plants.The results indicated that the capacity for the utilization and accumulation of nitrogen and phosphorus nutrients of emergent plants was higher than that of other aquatic plants.Among them,Canna indica exhibited the highest accumulation of total nitrogen(TN)and total phosphorus(TP)in the water,reaching up to 40.95 mg and 5.83 mg,respectively.The maximum uptake rate(Imax)of Acorus calamus was found to be higher than that of other aquatic plants,with values up to 1.428 mg·g^(-1)·d^(-1)and 0.313 mg·g^(-1)·d^(-1),respectively.The removal rates of TN and TP by emergent plants were all over 85%,contributing over 80%.The accumulation of sulfur is adverse to utilization and accumulation of nitrogen and phosphorus by aquatic plants.Among them,Canna indica with the least accumulation of sulfur showed the highest removal rate of nitrogen and phosphorus,up to 92.29%and 86.24%,respectively.Aquatic plants change the pH of the water during their growth,which in turn affects the uptake and accumulation of nitrogen and phosphorus by aquatic plants.In summary,emergent plants hold a better capacity for utilization and accumulation of nitrogen and phosphorus,and an excess of sulfur and a low pH in the culture system will reduce the utilization and accumulation of nitrogen and phosphorus by aquatic plants.