地衣芽孢杆菌与3种微藻生长的相互影响

为弄清水产养殖中常用的有益菌——地衣芽孢杆菌和3种常见的浮游微藻的相互关系，本文采用陈海水配制的无机培养液和对虾养殖池水，分别研究了地衣芽孢杆菌对微绿球藻、隐藻和颤藻的影响以及这几种微藻对地衣芽孢杆菌的反作用。以通径分析法分析微绿球藻、隐藻和地衣芽孢杆菌对颤藻直接和间接影响力的大小。结果发现，地衣芽孢杆菌对微绿球藻有一定的抑制作用，对隐藻的促进作用明显，而对颤藻的作用效果不明显；在与微绿球藻和隐藻混合培养时，地衣芽孢杆菌生长正常，仅在藻细胞密度较大时受到一定程度的抑制；在与颤藻混合培养时，地衣芽孢杆菌受到明显的抑制作用。通径分析结果发现，地衣芽孢杆菌与微绿球藻协同对颤藻产生抑制作用，而隐藻对颤藻的作用较弱。

The Interaction Between Bacillus Licheniformis and 3 Kinds of Microalga

In order to investigate the relationship between Bacillus Licheniformis and 3 kinds of Microalga in aquaculture, Nannochloropsis oculata, Cryptornonas erosa and Oscillatoria sp. had been cultivated in inorganic solution which was made up with aging seawater. The direct influence power and indirect influence power of Nannachloropsis oculata, Cryptomonas erosa and bacillus licheniformis had been studied with the path analysis method. The experimental results indicated that ：Bacillus licheniformis can inhibit Nannochloropsis oculata, promote Cryptomonas erosa growth but had no obvious effect on Oscillatoria sp.. The maximum biomass of Cryptomonas erosa was 392×10^4 cell·mL^-1 when it was mix-cultured with Bacillus Licheniformis and it was 182.3×10^4 cell·mL^-1 in single-culture groups. When mix bacillus licheniformis with Nannochloropsis oculata and Cryptomonas erosa,it could grow normally. The growth of Bacillus licheniformis will be inhibited only when the algal cell density was increased. But when mixed bacillus licheniformis with OsciUatoria sp., it was inhibited significantly. There was a significant negative correlation between Bacillus Licheniformis and Oscillatoria sp. （ r=-0.889, P=0.003 ）. The path analysis results indicate that：Bacillus licheniformis and Nannochloropsis oculata could synergistically inhibit Oscillatoria sp.. From the decision coefficient（R^2=-0.925 ）, we could see that Nannochloropsis oculata was the main limiting factor. Cryptomonas erosa had minor effects to Oscillatoria sp.. The decision coefficient of Cryptomonas erosa was 0.008 2.