The effect of extracellular products in each growth stage of Porphyra tenera for the growth of Licmophora sp. was examined.
The unialgal c ulture was incubated at 15°C in 12: 12h light-dark cycle and illuminatedb y cool white fluorescent lamps at 4,000-5,000 lux. The, results are as follows.
1) The growth was markedly promoted by the filtrate obtaine d from 0-31 days culture.
2) The exponential phase of the diatom was elongated by the filtrate from 31-5 5 days culture.
3 ) The mixed filtrates after 55-67 days (matured) were of no effect to the growth of Licmophora sp.