不同基因型水生植物对铵态氮和硝态氮吸收动力学特性研究

Study on the kinetic characteristics of ammonium and nitrate nitrogen uptaken by different genotypes aquatic plants

针对不同营养状况的富营养化水体修复而选择吸收养分效率较强的水生植物,采用改进常规耗竭法比较研究了6种不同基因型水生植物凤眼莲(Eichhornia crassipes Solms)、黄花水龙(Jussiaea stipulacea Ohwi)、再力花(Thalia dealbata Fraser)、美人蕉(Canna glauca L.)、水芹[Oenanthe javanica(Bl).DC]和豆瓣菜(Nasturtium officinaleR.Br.)对铵态氮和硝态氮吸收动力学特性。结果表明,不同基因型水生植物吸收铵态氮和硝态氮的动力学特性可用Michaelis-Menten方程来描述。在低浓度培养下,不同基因型水生植物对NH4+-N和NO3--N吸收的动力学参数Imax和Km差异较大,其吸收NH4+-N和NO3--N的Imax最大是水芹,其次是豆瓣菜;Km值最小的是水芹,其次是豆瓣菜;且水芹对NH4+-N和NO3--N不仅具有较强的亲和力,还具有较高的离子吸收速率。结果还表明,当介质中氮浓度较低时,水芹有优先吸收硝态氮的趋势,而豆瓣菜和再力花有优先吸收铵态氮的趋势。

The kinetic characteristics of ammonium nitrogen （NH4＋-N）and nitrate nitrogen （NO（3^-）-N）uptaken by six different genotypes aquatic plants such as Eichhornia crassipes Solms, Jussiaea stipulacea Ohwi, Thalia dealbata Fraser, Canna glauca L., Oenanthe javanica（B1）. D C., Nasturtium offtcinale R. Br., was studied with improved conventional exhaustion method, in order to select the proper aquatic macrophyte according to the status of eutrophic water. The results showed that the kinetic characteristics of NH4＋-N and NO3--N uptaken by different genotypes aquatic plants could be illustrated with the Michaelis-Menten equation. There were very big difference between the Imax and Km of NH（4^＋）-N and NO（3^-）-N uptaken by different genotypes aquatic plants under low concentration, the biggest Imax of NH（4^＋）-N and NO（3^-）-N uptaken was Oenanthe javanica （B1）. D C, next was Nasturtium officinale R.Br, and the smallest Km of NH（4^＋）-N and NO（3^-）-N uptaken was Oertanthe javanica （B1）. D C, next was Nasturtium officinale R. Br. In addition, Oenanthe javanica （B1）. D C not only has the strong affinity with NH（4^＋）-N and NO（3^-）-N, but also has the high ion absorption rate. The result also indicated that Oenanthe javanica（B1）. DC fias the preferential absorption NO（3^-）-N trend, but Thalia dealbata Fraser and Nasturtium offtcinale R. Br have preferential absorption NH4＋-N trend when the nitrogen concentration is low in the medium.