[Response of Prorocentrum minimum growth to zinc limitation]

Studies on the growth and physiological response of red tide alga Prorocentrum minimum to three Zn2+ levels were showed that the specific growth rate and biomass were limited in low Zn(2+)-grown cells (1.4 pmol.L-1, which were 0.40 d-1 and 51,100 cell.ml-1 respectively. The specific growth rate was not significantly different when the Zn2+ concentration in medium was increased over 24.4 pmol.L-1, but there was a slight decrease in biomass; however, both specific growth rate and biomass were much higher than those in low Zn(2+)-grown cells. It was also showed that chlorophyll a synthesis was limited due to Zn2+ deficient, and therefore, the cells became light saturated at higher irradiance under Zn-limited condition. Light-saturated photosynthetic rates (Pm) and photosynthetic efficiency (alpha) increased significantly with increasing Zn2+ concentrations. It was concluded that Zn2+ concentration might be one of the key factors affecting red tide blooms in eutrophication environment.