Effect Of Allelopathy Among Four Marine Microalgae

Allelopathy of four marine microalgae, Prorocentrum donghaiense, Phacodactylum tricormutum, Dannochloropsis oculata, and Scrippsiella trochoidea was studied by measuring cell density, biomass, and activity of SOD for algal acceptors. The results showed that the growth of N. oculata was promoted by P. tricormutum, S. trochoidea, and P. donghaiense, the cell density increased about 21%²30%, 36%⁸37% and 60%¹89% when it was incubated in the filtrate of those three species. However, the growth of P. donghaiense was inhibited up to 99% after 10-day incubation in the filtrates of other three algal species. There were no significant allelopathic effect on P.tricornutum or S.trochoidea by P. donghaiense, the between P. tricornutum or S. trochoidea. The inhabitation on the growth of P. donghaiense by P. tricornutum increased as the concentration of filtrate increased. The growth of N. oculata had the highest increase under the filtrate of 10⁵ cell · ml^-1 among 5 different concentration levels. The SOD of N. oculata is higher than that of P. donghaiense in all incubations in the filtrate of P. tricornutum. Temperature and pressure can both affect the allelopathy of P. tricornutum, and the inhabitation on P. donghaiense was higher when P. tricornutum was treated with high temperature and pressure.