Optimal Light Intensity and Nitrogen-toPhosphorus Ratio for Growth of Nitzschia capitellata Hust.

目的]为进一步探索小头端菱形藻（Nitzschia capitellata Hust.）作为优质饵料、生物能源的潜能，在室内条件下对小头端菱形藻生长的最适光照强度、氮磷比等培养条件进行研究。方法]设定不同光照度梯度，在相同营养、温度（25±1）℃以及光周期（12 h/12 d）下进行培养，筛选得出最适光照强度，其次将氮磷比设置为5∶1、6∶1、7∶1和8∶1，置于相同条件进行培养。结果]在3000 lx的光照度下，小头端菱形藻的藻比增殖率和现存量最高，分别为0.51 d-1和7.97×104 cells/ml。在氮磷比为6∶1条件下，小头端菱形藻生长最佳。结论]小头端菱形藻的最适光照度为3000 lx，最适氮磷比为6∶1。

Optimal Light Intensity and Nitrogen-to- Phosphorus Ratio for Growth of Nitzschia capitellata Hust,

Objective] The aim was to explore the potential of Nitzschia capitel ata as excel ent baits and bioenergy, and the optimal light intensity and nitrogen-to-phos-phorus （N/P） ratio suitable for its growth were researched as wel . Method] With light intensity gradient set, Nitzschia capitel ata was cultured with the same nutrients at （25 ±1） ℃ and light cycle at 12 h/d to select optimal light intensity. Then, Nitzschia capitel ata was cultured with the same condition, and nitrogen-to-phospho-rus ratios at 5∶1, 6∶1, 7∶1 and 8∶1. Result] With light intensity at 3 000 lx, specific growth rate and standing stock achieved the highest at 0.51 d-1 and 7.97×104 cel s/ml. The growth condition with nitrogen-to-phosphorus ratio at 6∶1 was the most suitable for Nitzschia capitel ata growth. Conclusion] The optimal light intensity and nitrogen-to-phosphorus ratio were 3 000 lx and 6∶1, respectively, for Nitzschia capitel ata.