NO2——N对铜绿微囊藻生理特性的影响

采用藻类生物测试标准方法研究了不同NO2--N初始浓度条件下铜绿微囊藻(Microcystis aeruginosa)的生长及生理变化.结果表明,相对BG11(NO2--N初始浓度为0)培养基,低初始NO2--N浓度(1,10mg/L)条件下铜绿微囊藻生长良好;高NO2--N初始浓度(20,30,40mg/L)条件下藻生长缓慢甚至停滞. NO2--N初始浓度由10mg/L到30mg/L,亚硝酸还原酶(NiR)活性和过氧化氢酶(CAT)活性呈增加趋势;在NO2--N初始浓度分别为20~30mg/L和20~40mg/L时,叶绿素a(Chl-a)含量和丙二醛(MDA)含量随NO2--N浓度增大而逐渐升高;在初始NO2--N浓度0,1,10,20,30mg/L条件下硝酸还原酶(NR)没有明显变化.这表明,铜绿微囊藻在NO2--N初始浓度10,20,30mg/L条件下能维持一定的生长,主要由于藻叶绿素含量的增加,NiR活性和防止细胞过氧化的酶CAT活性的提高所致.

Effect of NO2--N on the physiology characteristics of Microcystis aeruginosa

The growth and physiological change of Microcystis aeruginosa were studied under different initial NO2--N concentration, adopting the standard method of algal bioassay. Compared with BG11 (without NO2--N), M. aeruginosa grew well under low initial NO2--N concentration (1 and 10mg/L), however, the growth slowed down and even ceased under high initial NO2--N concentration (from 20 to 40mg/L). The nitrite reductase (NiR) activity and catalase (CAT) activity tended to increase from initial NO2--N concentration of 10 to 30mg/L. The content of chlorophyll a (Chl-a) and malondiadehyde (MDA) also showed an increase with initial NO2--N concentration increasing in the range of 20 to 30mg/L and 20 to 40mg/L respectively. The nitrate reductase (NR) activity was constant under initial NO2--N concentration (from 0 to 30mg/L). These observed phenomena indicated M. aeruginosa could maintain definite growth in initial NO2--N concentration rage of 10 to 30mg/L, due to the increase of Chl-a content and the enhancing of enzymic activity of NiR and CAT.