Effect of nitrogen and phosphorus level on growth, development and biochemical composition of Neoporphyra haitanensis conchocelis

Neoporphyra haitanensis is an important economic alga. A 3 x 2 factorial layout containing three nitrogen levels (1, 5, 10 mg L-1) and two phosphorus levels (1, 5 mg L-1) were designed to examine the effect of nitrogen and phosphorus levels on physiological responses of N. haitanensis conchocelis during growth phase (trial I) and development phase (trial II). In trial I, a higher phosphorus concentration inhibited the relative growth rate of N. haitanensis conchoceli at each nitrogen level. Contents of chlorophyll a and carotenoids were higher at high nitrogen level. Contents of phospholipids were higher at high phosphorus concentration at 5 mg L-1 nitrogen level. In trial II, high phosphorus concentration increased the formation of conchosporangia at 1 mg L-1 nitrogen level. Higher contents of phycoerythrin and phycocyanin were at high nitrogen level. Higher contents of phospholipids were at high phosphorus concentration at 1 mg L-1 nitrogen level. Higher contents of triglycerides were at low nitrogen level both in trial I and II. These results indicated that high nitrogen level increased the contents of pigment. High phosphorus level favoured the formation of conchosporangia and deposition of phospholipids. These results lay the groundwork for research into mechanism of growth and development of N. haitanensis.