高铵条件下绿狐尾藻的生理与氮磷吸收特征

Physiological Characteristics and Nitrogen and Phosphorus Uptake of Myriophyllum aquaticum Under High Ammonium Conditions

为了探讨水生植物绿狐尾藻(Myriophyllum aquaticum)在生态湿地系统对高铵态氮(NH_4^+-N)的耐受及氮(N)、磷(P)吸收能力,试验设置3个高NH_4^+水平(70、210、420 mg·L^(-1))的营养液,对绿狐尾藻培养21 d,研究高浓度NH_4^+对绿狐尾藻生理及N、P吸收特征的影响.结果表明,70 mg·L^(-1)高NH_4^+处理,绿狐尾藻生长健壮,培养21 d后,茎高和生物量分别达到40.56 cm和17.82 g·穴-1;与70 mg·L^(-1)高NH_4^+对照相比,210 mg·L^(-1)高NH_4^+处理下,绿狐尾藻丙二醛含量显著增加,但叶绿素和可溶性糖含量仍较高,说明其受到一定NH_4^+的胁迫,但不影响其正常生长,茎和生物量的生长速率与对照无显著差异.当NH_4^+水平达到420 mg·L^(-1)时,丙二醛含量增加了2倍,茎高和生物量生长速率仅为对照的27.4%和17.9%,植物受到严重胁迫,生长受阻甚至死亡.3种高NH_4^+处理下,绿狐尾藻总N和总P含量的变化范围为30.7~53.4 mg·g^(-1)和3.8~7.7mg·g^(-1),表现出对N、P超高的吸收能力.鉴于绿狐尾藻在高浓度NH_4^+-N中的高耐受性,及很强的N、P吸收能力,绿狐尾藻可作为高铵/氨废水生物处理中理想的湿地生物,将具有良好的应用前景.

Ammonium nitrogen（ NH4^＋-N） at high concentrations is toxic to plants. In order to explore the NH4^＋-N tolerance of Myriophyllum aquaticum（ M. aquaticum） and its ability of nitrogen（ N） and phosphorus（ P） uptake,this study used a nutrient solution with three NH4^＋-N levels（ 70,210,420 mg·L^-1） to incubate M. aquaticum for 21 d. The characteristics of plant physiology and N and P uptake of M. aquaticum were measured. At NH4^＋-N of 70 mg·L^-1,M. aquaticum grew healthily,and shoot height and biomass linearly increased with the increase incubation time. Relative shoot height and biomass of M. aquaticum were 40. 56 cm and17. 82 g·hole-1on day 21,respectively. Compared to the control with 70 mg·L^-1ammonium,malondialdehyde（ MDA） content of M. aquaticum was significantly increased; chlorophyll and soluble sugar contents were also high at NH4^＋-N of 210 mg·L^-1. M.aquaticum suffered from the NH4^＋-N stress. However,the stress of 210 mg·L^-1NH4^＋-N did not affect its normal growth and there was no significant difference in the relative growth rate of the shoot height and biomass compared with the control. At NH4^＋-N of 420mg·L^-1,MDA contents of M. aquaticum doubled and the shoot height and biomass growth rate were only 27. 4% and 17. 9% of those for 70 mg·L^-1NH4^＋-N,indicating that M. aquaticum was subjected to serious stress that caused unhealthy growth or even death. At three NH4^＋-N levels,the ranges of N and P content of M. aquaticum were 30. 7-53. 4 mg·g^-1and 3. 8-7. 7 mg·g^-1,respectively,which indicated that M. aquaticum had a high uptake capacity of N and P. M. aquaticum is an ideal wetland plant that has a good application prospect for constructed wetlands in biological treatment of high-ammonia wastewater.