氮磷限制条件下螺旋鱼腥藻伪空胞合成及其浮力特征

Study on Formation of Gas Vesicles of Anabaena spiroides under NitrogenLimited and Phosphorus-Limited Conditions

伪空胞的合成与破裂是蓝藻浮力调节的主要方式.为研究固氮蓝藻浮力的形成及其调节能力,以螺旋鱼腥藻为代表,在外压作用下将螺旋鱼腥藻伪空胞压破,分别在氮限制〔ρ(TN)为1.65 mg/L,ρ(TP)为1.780 mg/L〕、磷限制〔ρ(TN)为16.50 mg/L,ρ(TP)为0.178 mg/L〕条件下研究伪空胞的合成、藻细胞垂向迁移及漂浮特性.结果表明:螺旋鱼腥藻的伪空胞完全破裂后,在氮限制条件下,藻细胞恢复浮力(漂浮率>50%)需56 h,伪空胞含量恢复到初始水平(2.47×10-7μL/cell)需要72 h;而在磷限制条件下伪空胞含量无法恢复到初始水平;氮限制和磷限制条件下螺旋鱼腥藻最大垂向迁移速率分别为1.4和0.8 m/d,磷限制条件对螺旋鱼腥藻伪空胞的合成及恢复更为不利.

Production and dilution of gas vesicles and irreversible collapse of gas vesicles are the main mechanisms of buoyancy regulation of Cyanobacteria.Buoyancy and buoyancy regulation ability are factors forming the competitive advantage of Cyanobacteria,while buoyancy regulation ability is the important factor in bloom formation.The present study investigated gas vesicles,vertical migration rate and buoyancy regulation of Ananbaena sp..The species was pressured and collapsed gas vesicle by external forces and then cultivated in nitrogen-limited（ρ（TN） = 1.65 mg/L,ρ（TP） = 1.780 mg/L） and phosphorus-limited（ρ（TN） = 16.50 mg/L,ρ（TP） = 0.178 mg/L）environments.The results showed that after the gas vesicle collapse,for cells under the condition of nitrogen limitation,restoration of buoyancy required 56 h,and gas vesicle restoration to the initial state required 72 h.Gas vesicles of Anabaena sp.under phosphoruslimited could not restore to the initial state.The maximum rising rate of the cells under the nitrogen-limited and phosphorus-limited conditions were 1.4 and 0.8 m/d,respectively.