Growth and photosynthesis limitation of marine red tide alga Skeletonema costantum by low concentrations of Zn~2+

摘要

The specific growth rate,cell final yields and extracellar carbonic anhydrase activity of the red tide alga Skeletonema costatum increased with increasing concentrations of Zn~2+ from 0 to 12 pM,but decreased when Zn~2+ was over 24 pM.However,cells grown under high concentrations of Zn~2+ had higher activities of intracellular carbonic anhydrase than those grown under low concentrations of Zn~2+.Chlorophyll alpha-specific light-saturated photosynthetic rate(p_m~chla),dark respiration rate(R_d~chla),dark respiration rate(R_d~chla)and apparent photosynthetic efficiency(alpha~chla)significantly increased with increasing concentrations of Zn~2+ from 0 t0 3 pM,but decreased when increasing concentrtions of Zn~2+ from 3 to 66 pM.Photorespiration is the lowest when cells cultured in 3 pM Zn~2+.The results suggest physiological activity of Skeletonema costatum is very sensitive to the prevailing concentration of Zn~2+.