N/P对菱形藻生长速率和营养成分含量的影响

研究了N/P(1∶1、5∶1、12.5∶1、30∶1、50∶1、80∶1)对菱形藻的生长速率、营养成分含量及氮磷利用率的影响。试验结果表明,(1)N/P对菱形藻的生长影响显著(P0.05),其中N/P为12.5∶1时,比生长速率最大,当N/P5∶1和N/P50∶1时,菱形藻的生长较慢,比生长速率为0.3～0.6/d;(2)藻细胞营养成分的含量也受N/P的影响:在N/P为12.5∶1时,叶绿素的含量达到1.81g/ml,总脂肪、蛋白质、胞外多糖和胞内多糖的含量分别占干质量的29.9%、17.8%、15.3%、14.2%,高于其他N/P下的营养成分含量;(3)培养后水体中氮磷的含量明显下降,TN的利用率之间有显著性差异(P0.05),利用率均超过55%,最高为30∶1,达78%,TP的利用率之间无显著性差异(P0.05),均高于90%。

Effects of N/P Ratio on Growth and Nutrient Contents in Alga Nitzschia sp.

The growth and nutrient contents in alga Nitzschia sp. were studied under different ratios of nitrogen to phosphorus(1:1,5:1,12.5:1,30:1,50:1,and 80:1)to evaluate the uptake ratio of nitrogen to phosphorus. It was found that there was significant differences in growth rate(P<0.05),the maximum at N/P=12.5:1,and the minimum at N/P<5:1 and N/P>50:1.The nutrient contents were obviously in accordance with the growth. There were chlorophyll c(P>0.05)ontent of 1.81 g/ml,29.9% of extracellular polymeric substance(EPS),17.8% of intracellular polymeric substance(IPS),5.3% of protein and 14.2% of lipid in the alga at N/P=12.5:1,higher than those at other ratios of nitrogen to phosphorus.After being cultivated,there was much lower N and P levels in the water media after culture,indicating that there were significant differences in the uptake ratio of total nitrogen(TN),over 55%(the maximum of 78% at N/P=30:1)(P<0.05). However,there were no significant differences in the uptake ratio of total phosphorus(TP),over 90%.