氮、磷供给水平对纤细角毛藻生长及细胞物质组成的影响

Effects of nitrogen and phosphorus supplies on the growth and intracellular composition for Chaetoceros gracilis

纤细角毛藻(Chaetoceros gracilis)具有丰富的营养组成,是重要的生物饵料微藻。该试验以f/2培养基中标准的氮磷供给水平为基准,进行不同氮磷供给水平对纤细角毛藻生长及细胞物质组成的研究。结果表明,基准浓度的1/2倍及以下的低氮供给使纤细角毛藻的生物量减少严重,而基准浓度的2倍、3倍高氮供应下仍与基准氮供给相差不大。高于基准磷浓度供给促进纤细角毛藻的生长,其中基准磷浓度的3/2倍最优。在提高纤细角毛藻生物量产量方面,改变磷供给浓度比氮更有效。在细胞物质组成方面,基准浓度的3/2-3倍的高氮供给是提升细胞蛋白质含量的有效手段,而磷浓度变化对蛋白质含量的影响较低。细胞总糖含量的提升可通过降低磷供给水平(1/8-1倍基准浓度)实现。降低氮供应至基准浓度的1/8~1/4倍或者降低磷供应至基准浓度的1/8~1/4倍的寡营养条件,均能有效提高细胞脂肪含量,其中1/8倍的磷供给浓度对于提高脂肪含量效果最好。综合而言,纤细角毛藻的生长和细胞物质组成受磷营养供给的影响大于氮供给。

Chaetoceros gracilis is an important biological food microalgae with rich nutritional composition.In the experiment,the respective nitrogen and phosphorus supply levels in the standard f/2 medium were used as the referencesto study the growth and intracellular composition of C.gracilis under different nitrogen and phosphorus supplies.The results showed that the low nitrogen supply of 1/2 folds of the referencenitrogen concentration and below reduced the biomass of C.gracilis seriously,while the high nitrogen supply of 2 and 3 folds of the referencenitrogen concentration was still not much different from the reference nitrogen supply.Phosphorus supply higher than the reference phosphorus concentration promotes the growth of C.gracilis,and 3/2 fold the referencephosphorus concentration was optimal one.Aiming on increasing the biomass production of C.gracilis,increasing the concentration of phosphorus was more effective than increasing the concentration ofnitrogen.In terms of intracellular composition,a high nitrogen supply of 3/2-3 folds of referencenitrogen concentration was an effective means to increase cell protein content,while changes in phosphorus concentration had a lower impact on protein content.The increase in sugar content could be achieved by reducing the phosphorus supply to 1/8-1 folds ofreference phosphorus concentration.Oligotrophic conditions that reduce the nitrogen supply to 1/8-1/4 folds or reduce the phosphorus supply to 1/8-1/4 folds of respective the reference concentration could effectively increase the cell lipid content,among which 1/8 folds of the referencephosphorus concentration had the highest increasedlipid content.In summary,the growth and intracellular composition of C.gracilis was more significantly affected by phosphorus supply than nitrogen supply.