Suppressive effect of germanium dioxide on diatom contamination during cultivation of Saccharina japonica young sporophytes

LI Tao1,2 WANG Fei-jiu2 SUN Xiu-tao2 WANG Wen-jun2 LIU Fu-li2 DING Chang-ling2 LIANG Zhou-rui2 LIU Kun2(1 College of Animal Science,Qingdao Agricultural University,266109)(2 Key Laboratory of Sustainable Utilization of Marine Fisheries,Ministry of Agriculture,Yellow Sea Fisheries Research Institute,Chinese Academy of Fishery Sciences,Qingdao 266071)

Germanium dioxide Saccharina japonica sporophytes Nitzschia sp.Chlorophyll fluorescence technique

In the present study,using the chlorophyll fluorescence technique,the suppressive effect of germanium dioxide(GeO2)on Nitzschia sp.contamination during the cultivation of Saccharina japonica seedling was investigated with the photosystem II maximum fluorescence yield(Fv/Fm) as the index.The results showed that: 1) When the concentration was above 5mg/L,GeO2 affected Fv/Fm value of Nitzschia sp.significantly,whereas when the concentration was 15mg/L or above,GeO2 had lethal effect on Nitzschia sp.;2) To the young sporophytes of S.japonica,GeO2 at concentrations of 20mg/L or above affected the Fv/Fm value significantly,whereas GeO2 at concentrations of 30mg/L or above had lethal effect on young sporophytes;3) To the young sporophytes contaminated by Nitzschia sp.,the Fv/Fm value was affected significantly by GeO2 at concentrations of 15 mg/L or above,while the contaminated young sporophytes died when GeO2 concentration was 20 mg/L or above.Comparatively,GeO2 at concentrations of 5～15 mg/L could suppress the photosynthesis of Nitzschia sp.significantly,but only had a minor effect on photosynthesis of S.japonica young sporophytes.Therefore,GeO2 at concentrations of 5～15 mg/L could prevent the Nitzschia sp.contamination during the cultivation of S.japonica young sporophytes.The results obtained from the present study could provide the basis for preventing the Nitzschia sp.contamination during the cultivation of S.japonica young sporophytes.