高浓度氨氮或磷胁迫对亚洲苦草生理特性的影响

Physiological Responses of Vallisneria asiaticato the Stress of High Concentrations of Ammonia N or P

为阐明富营养化水体中沉水植物消失的机理,以高等水生植物亚洲苦草(Vallisneria asiatica)为研究对象,通过室内模拟试验,研究了富营养化水体中高浓度氨氮或高浓度磷胁迫对亚洲苦草生理特性的影响。结果表明:与中浓度氮、磷营养盐(1.50mg/L的NO_3^--N和0.10mg/L的PO_4^(3-)-P)处理相比,高浓度氨氮(3.50mg/L的NH+4-N)和高浓度磷(0.60mg/L的PO_4^(3-)-P)都对亚洲苦草造成了严重的氧化胁迫,导致亚洲苦草叶片中叶绿素a和蛋白质含量减少,过氧化氢酶(CAT)活性增加;过高浓度的氨氮或磷虽然可以激活亚洲苦草的抗氧化保护体系,但是不能避免亚洲苦草受到氧化损伤;在富营养化水体中进行亚洲苦草恢复时,氮、磷营养盐浓度的双重控制是保证亚洲苦草成功恢复的非常重要的前提。

To clarify the disappearance mechanism of submerged macrophyte in entrophic waters,this paper studies the physiological effects of high concentrations of ammonia N or P in the water on Vallisneria asiatica with a 20-day aquarium experiment.The physiological indexes of V.asiaticaare measured before and after the experiment.The results show that compared with the moderate concentration of nutrients（1.5 mg/L NO3^--N and 0.10 mg/L PO4^3--P）,either excessive ammonia N（3.50 mg/L NH4^＋-N）or phosphorus（0.60 mg/L PO4^3--P）could cause the oxidative stress to cells of V.asiatica,expressed as decreased contents of chlorophyll a and protein,and the enhancement of catalase（CAT）activities in the leaves of V.asiatica.It reveals that the antioxidant protection system in V.asiaticacould be activated but still could not prevent the damages to V.asiaticaexposed to either excessively high concentrations of ammonia nitrogen or phosphorus.Therefore,it is necessary to establish a dual control strategy of N and P for the restoration of V.asiaticain eutrophic waters.