Production and Releasing of the Growth-Inhibitor Formed by Isochrysis galbana

In order to elucidate the production and releasing process of the growth-inhibitor formed by Isochrysis galbana,the effects of the different cultural liquids on the growth of Chaetoceros muelleri andPhaeodactylum tricornutum were investigated,and those cultural liquids contained re-suspended cells,broken cells,cultural liquid of no cells,cellular fragments and free-cell medium which were obtained at the exponential,stationary and death phases of Isochrysis galbana,respectively.The results showed that the process of the production and releasing of the growth-inhibitor had very close relationship with the cell age of Isochrysis galbana.It could be concluded that the growth-inhibitor was produced gradually from the exponential growth phase of Isochrysis galbana and mostly accumulated in the cells up to the stationary phase.When the concentration of the growth-inhibitor in the cells was beyond a lethal level,the growth-inhibitors in the dying or dead cells were released into the cultured medium,which caused that the concentration of the growth-inhibitor rapidly increased in the cultured medium.