不同浓度NH_4^+对黄菖蒲抗氧化酶系统的影响

Effects of Different Concentrations of NH_4^+ on the Antioxidant System of Iris pseudacorus L.

通过追踪测定黄菖蒲叶绿素a、丙二醛(MDA)含量及超氧化物歧化酶(SOD)、过氧化物酶(POD)活性,研究了不同浓度NH4+对黄菖蒲抗氧化酶系统的影响。结果表明,NH4+质量浓度为0.5和1 mg/L时,黄菖蒲各理化指标变化平缓,0.5~1 mg/L是黄菖蒲生长的适宜的NH4+质量浓度;而在ρ(NH4+)≥3 mg/L时,NH4+对黄菖蒲产生了明显的胁迫作用,表现为在培养过程中,黄菖蒲叶绿素a含量逐渐降低,SOD及POD活性呈现先增加后逐渐降低的趋势,MDA含量逐渐增加,表明高浓度NH4+在经过一段时间的胁迫后,能够显著抑制黄菖蒲SOD及POD的活性,引起细胞的氧化损伤,并能促进叶绿素的分解,从而影响黄菖蒲的生长。

The effects of d ifferent concentrations of NH4＋ on antioxidant system of Iris pseudacorus L. was studied by determining the chlorophyll-a content, MDA content, SOD and POD activities of Iris pseudacorus L.. Results showed that the growth of Iris pseudacorus L. was fitting at 0.5 and 1 mg/L concentrations of NH4＋, and the physical and chemical indicators relatively mildly changed. But when NH4＋ concentration was more than 3 mg/L, it had strong stress on Iris pseudacorus L.. Chlorophyll-a content of Iris pseudacorus L. declined gradually from the beginning, and MDA content of Iris pseudacorus L. increased gradually from the beginning, whereas SOD and POD activities increased first, but decreased as treatment time went on, indicating that the high concentration of NH4＋ inhibited SOD and POD activity after a long incubation, caused oxidative damage to cells and promoted the degrading of chlorophyll of Iris pseudacorus L. which might be one of its mechanisms of restraining Iris pseudacorus L..