氮磷限制条件下螺旋鱼腥藻产生土嗅素特征研究

采用批量培养的方法研究了螺旋鱼腥藻在氮限制和磷限制条件下生长与土嗅素的产生特征.在磷限制条件下螺旋鱼腥藻的生长速率降低,不易生成异形胞;而在氮限制下鱼腥藻生长良好,并生成异形胞,异形胞形成的比例为3.5%~4.4%.在磷限制和氮限制条件下,单位细胞土嗅素的浓度在培养的前20d内都处于急速下降的趋势,之后开始趋于平缓,分别维持在3.18×10-5,3.68×10-5ng/cell左右.氮限制条件下螺旋鱼腥藻单位细胞土嗅素的生成量略高于磷限制条件下.氮限制条件下,螺旋鱼腥藻单位细胞叶绿素a的生成量高于磷限制条件下.螺旋鱼腥藻单位细胞产生的土嗅素与叶绿素a的质量比(geosmin/Chl a)在磷限制条件下要高于氮限制条件下.

Geosmin production characteristics by Anabaena sp. in nitrogen-limited and phosphorus-limited conditions

Characteristics of Geosmin produced by Anabaena sp. under phosphorus-limited and nitrogen-limited conditions were investigated in batch cultivation and determined using SPME-GC Mass. Anabaena sp. grew well and the growth rate was not influenced by nitrogen limitation. However, its growth was restrained by phosphorus limitation. Heterocyst was produced and its percentage account for 3.5%~4.4% of total cells under nitrogen-limited condition, whereas heterocyst was not produced under phosphorus-limited condition. The geosmin content in cell declined quickly in the first 20d and then kept almost constant. The geosmin content in the late phase was 3.7×10-5ng/cell under nitrogen-limited condition and was a little higher under phosphorus-limited condition (3.2×10-5ng/cell). Chl a concentration under the nitrogen-limited condition was much higher than that under phosphorus-limited condition. The ratio of geosmin content to Chl a content (geosmin/Chl a) under the phosphorus-limited condition (2.3×10-2) was higher than that under nitrogen-limited condition (1.5×10-2).