Studies On The Allelopathy Of Alexandrium. Tamarense

In recent years, the harmful alga blooms (HABs) broke out frequently in the sea area of China, and it exerted a tremendous influence on the ecology of the marine, sea fishery and the life of human-beings. Allelopathy was an important mechanism of the competition and succession between alga species. In order to definitude the allelopathy of A. tamarense on P. donghaiense, illustrate the relationship between A. tamarense on P. donghaiense, explore the mechanism of bilateral harmful alga blooms between A. tamarense on P. donghaiense, and provide the new thought for the management of the HABs, the effect of A. tamarense on different alga species was detected. Under the different nutrient conditions, the influence of the live globe, cell-free filtrate of A. tamarense and the hemolytic toxins from the filtrate on P. donghaiense was explored. It was also researched that the effect of live globe, cell-free filtrate, hemolytic toxins and PSP of the different strain A. tamarense on P. donghaiense.Alexandrium tamarense was showed to have significantly inhibition on the growth of three harmful algal blooms (HABs) speceies, Chattonella marina, Prorocentrum donghaiese and Heterosigma Akashiwo. The changes in growth of C. marina, P. donghaiese and H. akashiwo varied with the differences in ratios of cell density when co-cultured with A. tamarense. In the ratio of 1:1 (A. tamarense : P. donghaiese) and 1:3, P. donghaiese was inhibited considerably whereas it did not significantly differ from the control in 1:9. The filtrates from A. tamarense in the EP had stronger inhibition on the other three HABs algae than that in the SP. Under the different nutrient conditions, the live globe and cell-free filtrate of A. tamarense had a remarkable inhibition on P. donghaiese. The inhibition was more apparent under the N-, Fe-limited condition. The haemolytic activities of filtrate were various under different nutrient conditions as follows, N-limited>Fe- limited>non- and P-limited.