通过实验室静态模拟,研究了在富营养条件下(4.0 mg·L^-1TN,0.2 mg·L^-1TP)不同比例铵态氮和硝态氮(6∶0、5∶1、3∶3、1∶5和0∶6)对苦草〔Vallisneria natans(Lour.)Hara〕的生长与生理指标的影响。结果表明,随着铵态氮和硝态氮比例的下降,苦草相对生长率和蛋白质含量先升高后下降,超氧化物歧化酶(SOD)和谷氨酰胺合成酶(GS)活性逐渐下降,硝酸还原酶(NR)活性逐渐升高。在4.0 mg·L^-1TN和0.2 mg·L^-1 TP条件下,若不考虑磷的作用,高浓度铵态氮对苦草的生理功能有影响,对其生长有明显的抑制作用;而当铵态氮浓度小于0.67 mg·L^-1时却可以促进苦草的生长。 

The effects of different ratios of  NH₄⁺-N to NO₃^—N (6∶0, 5∶1, 3∶3, 1∶5and 0∶6)on growth and physiological indexes of Vallisneria natans(Lour.)Hara and the mechanism were investigated under eutrophic nutrient condition(4.0mg·L^-1TN and 0.2mg·L^-1TP)by the static laboratory experiment. The results showed that relative growth rate and protein content first increased significantly then decreased, the activities of super oxide dismutase(SOD)and glutamine synthetase (GS) decreased gradually, the activity of nitrate reductase(NR) increased gradually with decrease of ratio of NH₄⁺-N to NO₃^—N in culture medium. The results indicated that when concentrations of TN and TP were set, the increase of NH₄⁺-N concentration in water could exerta stress influence on normal growth of V. natans. When the concentration of NH₄⁺-N was lower than 0.67mg·L^-1,the growth of V. natans was promoted.