摘要:
从滇池分离纯化了两种常见水华微囊藻即铜锈微囊藻和绿色微囊藻。在常规培养条件下,两种藻类在对数生长期的生长速率μ值分别为0.61和0.63;早期生长的抑制光强不大于100μmol m-2s-1。铜锈微囊藻主要产生3种微囊藻毒素:MYCST-RR,MYCST-YR和MYCST-LR,绿色微囊藻产生的主要微囊藻毒素为[Dha7]-MYCST-RR,和[Dha7]-MYCST-LR,另含有少量的[Dha7]-MYCST-YR。在低光强15μE m-2s-1时,毒素含量每毫克干重细胞达到3.127μg微囊藻毒素,当光强达到100μE m-2s-1时,毒素含量降低到每毫克干重细胞1.971μg;光强对毒素形成的影响受到温度的调节,而温度对毒素形成的影响不大。探讨了两种微囊藻细胞在不同光照强度下叶绿素荧光比值Fv/Fm的变化,此比值的变化可以间接反映细胞受外界光照强度抑制程度。
关键词:
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微囊藻
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滇池
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微囊藻毒素
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生长
Abstract:
Bloom- forming cyanobacteria Microcystis aeruginosa and M.viridis were isolated and purified from the eutrophic lake of Dianchi, Kunming in Southwestern China.At temperature 25℃ and light intensity at 80μE, the growth rate of M.aeruginosa and M.viridis were 0.61 and 0.63, respectively.It was shown that light intensity over 100μmol m-2s-1 had inhibited the growth of both species.In M.aeruginosa, three microcystins, MYCST-RR, MYCTS-YR and MYCST-LR were identified as major toxins; M.viridis produced two major toxins- [Dha7]-MYCST-RR and [ Dha7]-MYCST-LR, with [Dha7] -MYCST-YR as the minor component.It was revealed that light played an important role in regulating the contents of toxins, the highest toxin contents was found in low light intensity at 15μmol m-2s-1, while the lowest ones occurred at higher light intensity at 100μmol m-2s-1.The variation of temperature had little effect on toxin production.The implication of the chlorophyll fluorescence ratio of Fv to Fm in reflecting the cell ability to adapt light intensity has also been explored .
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