绿狐尾藻对不同铵硝配比的生理响应

Physiological Response of Myriophyllum aquaticum Exposed to Different NH/NO Ratios

为了探究高氨养殖废水中一定比例的硝态氮对绿狐尾藻(Myriophyllum aquaticum)生长及生理特征的影响,采用营养液培养,在总氮浓度为15 mmol/L的条件下,以纯铵处理为对照(CK),设置NH+4∶NO-3=3∶1(以N3∶1表示)和NH+4∶NO-3=1∶1(以N1∶1表示)两个处理,研究绿狐尾藻对不同铵硝配比的生理响应。结果显示,培养至第21天,N1∶1处理的相对生物量和相对茎高分别为13.17 g和35.31 cm,显著低于N3∶1(19.59 g,41.78 cm)和CK组(17.82 g, 38.82 cm)(P<0.05)。不同处理下叶片中的氮含量为50.38~58.82 mg/g,显著高于茎中氮含量26.96~35.42 mg/g;但叶片中磷含量5.17~7.38 mg/g显著低于茎中的磷含量8.44~9.88 mg/g(P<0.05)。培养至第21天时,CK、N3∶1、N1∶1处理之间的叶片磷含量(6.76、7.06、7.38 mg/g)差异均达到显著水平(P<0.05),表现为N1∶1> N3∶1>CK。N1∶1和N3∶1处理叶片(7.03、6.75 mg/g)和茎中(6.43、5.04 mg/g)的可溶性糖含量均显著高于CK(3.58、3.27 mg/g)(P<0.05)。N1∶1处理叶片和茎中的叶绿素含量均显著高于CK和N3∶1处理(P<0.05)。研究表明,当处理中添加少量或不添加硝态氮时,有利于绿狐尾藻生长和生物量增加;当处理中硝态氮含量相对较高时,植株叶绿素和可溶性糖含量增加,同时吸收磷的能力增强。绿狐尾藻在不同铵硝配比的水体中均能保持良好的生长状态和较强的氮磷吸收能力,该结果为绿狐尾藻高效净化不同来源的养殖废水提供了理论依据。

With the development of artificial wetland technology in recent years, the macrophyte Myriophyllum aquaticum has attracted attention for treatment of swine wastewater. The influence of nitrate(NO-3) levels on the growth and physiological characteristics of M. aquaticum under conditions of high ammonium(NH+4) was explored, using a 21 day hydroponics experiment to study the response of M. aquaticum to different NH+4/NO-3 ratios:100% NH+4(control), NH+4/NO-3= 3∶1 and NH+4/NO-3= 1∶1. On day 21, the relative biomass(13.17 g) and relative stem height(35.31 cm) of M. aquaticum in the 1∶1 treatment were significantly lower than those in the 3∶1(19.59 g, 41.78 cm) treatment and control(17.82 g, 38.82 cm)(P<0.05). The nitrogen content of leaves(50.38-58.82 mg/g) was significantly higher than the stem content(26.96-35.42 mg/g), while the phosphorus content of leaves(5.17-7.38 mg/g) was significantly lower than the stem content(8.44-9.88 mg/g)(P<0.05). On Day 21, the phosphorus content of leaves differed significantly among treatments(P<0.05), in the following order: NH+4/NO-3=1/1(7.38 mg/g)>NH+4/NO-3=3/1(7.06 mg/g)>control(6.76 mg/g). The soluble sugar content of stems(6.43,5.04 mg/g)and leaves(7.03,6.75 mg/g) in both treatments were significantly higher than in the control(3.27, 3.58 mg/g)(P<0.05). The chlorophyll content of stems and leaves were significantly higher in the 1∶1 treatment than either the 3∶1 treatment or control(P<0.05). Wastewater containing little or no nitrate benefits the growth of M. aquaticum stem height and biomass. When nitrate concentration in water was relatively high, the plant contents of chlorophyll and soluble sugar were high, and the uptake capacity of phosphorus was strong. In summary, M. aquaticum grows well and maintains strong nitrogen and phosphorus absorption capacity in waters with varying ratios of NH+4/NO-3. These results provide theoretical guidance supporting the use of M. aquaticum for purification of swine wastewater from different sources.