铵氮对铜绿微囊藻(Microcystis aeroginosa)FACHB905的生长、生化组成和毒素生产的影响

Effect of ammonium nitrogen on the growth,biochemical constitutes and toxin production of Microcystis aeroginosa FACHB905

研究了铵氮对铜绿微囊藻(Microcystis aeroginosa)FACHB905的生长、生化组成和毒素生产的影响.结果表明,铵氮不利于铜绿微囊藻的生长,藻细胞最大比生长速率的铵氮浓度为0.2 mmol/L;藻细胞生化组成与铵氮的消耗程度密切相关,铵氮缺乏时细胞叶绿素含量降低,细胞C/N比急剧升高,铵氮的存在显著降低GS酶活力;该藻株毒素主要为MC-LR和去甲基MC-LR(desmethylMC-MR),铵氮浓度为1.0 mmol/L时毒素含量最高,为(1.66±0.47)μg/mg.这些研究不仅有助于揭示氮源对铜绿微囊藻生长和产毒的影响机理,而且对于评估和预防有害蓝藻水华暴发具有重要意义.

The effect of ammonium nitrogen on the growth, biochemical constitutes and toxin production of Microcystis aeroginosa FACHB905 was investigated. The results showed that ammonium nitrogen was not a good nitrogen source for the growth of this strain. The highest specific growth rate （μmax） was at 0. 2 mmol/L of ammonium nitrogen. The algal biochemical constitutes changed dependently with the conentrations of ammonium nitrogen in the medium ; the strain contained less chlorophyll a, higher C/N ratio and greater GS activity under ammonium nitrogen deficiency than sufficiency. This strain contained two major microcystins, MC-LR and desmethylMC-LR. The strain had the highest total toxin content （ 1. 66 ± 0. 47 ） μg/mg at 1.0 mmol/L of ammonium nitrogen. The study was not only helpful to elucidate the mechanism of the effect of nitrogen source on the growth and toxin production, but also important in the evaluation and control of harmful cyanobacterium blooms.