绿藻栅藻对微囊藻的抑制效应及评价

INHIBITORY EFFECT OF SCENEDESMUS SP.ON MICROCYSTIS AERUGINOSA AND ITS EVALUATION

为筛选具有控制微囊藻水华潜力的绿藻,研究基于藻类之间的化感作用,对34株绿藻开展筛选及评价工作。结果发现,栅藻FACHB-1229的抑制率最高,其滤液对微囊藻FACHB-3550和FACHB-905的抑制率分别为53.95%和48.39%;通过对滤液中的物质进行GC-MS检测,推测该藻株的效应物质可能为邻苯二甲酸二(2-甲氧基乙基)酯。进一步对FACHB-1229生长和光合放氧、氨氮耐受等指标进行评价,结果发现:该藻株在孔板中的生长速率(0.38±0.06)/d高于微囊藻生长速率(0.13±0.03)/d;栅藻FACHB-1229的光合放氧速率高于同期测定的其他绿藻光合放氧速率,可达(229.91±10.49)μmol O_(2)/(mg Chl.a·h);同时该藻株对氨氮的耐受能力最强,在氨氮浓度为1888.60 mg/L时其生长速率可达(0.30±0.08)/d。此外,在与微囊藻FACHB-3550进行共培养时,栅藻FACHB-1229所占比例持续升高。综上,栅藻FACHB-1229具备与微囊藻竞争的优势,有望成为微囊藻水华生物控制的优选材料。

Cyanobacterial harmful algal blooms are a global environmental problem.Microcystis,which can produce microcystin,is one of the most pervasive bloom forming cyanobacteria in freshwater ecosystems.Blooms of Microcystis have adverse effects on lake ecology,and may effect human health,so it is important to control Microcystis blooms.In order to investigate the inhibitory effect of green algae on Microcystis aeruginosa based on allelopathy among different algae strains,we screened potential green algae to control M.aeruginosa blooms.One strain which has allelochemicals production properties was screened from 34 strains of green algae.The results showed that the spent medium of Scenedesmus sp.FACHB-1229 had the highest inhibition rate,for M.aeruginosa FACHB-3550 was 53.95%and for FACHB-905 was 48.85%,respectively.Result of gas chromatography mass spectrometry(GC-MS)indicated that 1,2-Benzenedicarboxylic acid,bis(2-methoxyethyl)ester might be the allelochemical substances.In addition,we also measured growth rates,high ammonia nitrogen tolerance and photosynthetic oxygen evolution rates of the strain.The results indicated that Scenedesmus sp.FACHB-1229 had high specific growth rate of(0.38±0.06)/d.It also had the highest photosynthetic oxygen evolution rates of(229.91±10.49)μmol O_(2)/(mg Chl.a·h).The ammonia nitrogen tolerance of Scenedesmus sp.FACHB-1229 was significantly higher than other strains,its growth rate was(0.30±0.08)/d when the ammonia nitrogen concentration reached up to 1888.60 mg/L.Moreover,the proportion of FACHB-1229 was consistently increased when co-cultured with FACHB-3550.In summary,FACHB-1229 has the superiority in interspecies competition with M.aeruginosa,its spent medium can inhibit the growth of M.aeruginosa,and it also has high ammonia nitrogen tolerance and photosynthetic oxygen evolution rate.Therefore,this study has provided the theory and application basis in prevention and control of cyanobacterial blooms using interspecific competition among algae.FACHB-1229 has the potential to control harmful algae through biological methods,it can grow rapidly in aquaculture pond or other polluted water bodies with high ammonia nitrogen concentration,while it can inhibit M.aeruginosa through allelopathy and provide dissolved oxygen at the same time.