Applications Of Imaging Flow Cytometry In Phytoplankton Research

Imaging flow cytometry is a new technology that combines the high throughput and strong statistical capabilities of flow cytometry and the imaging capabilities of microscopy.It overcomes many limitations of traditional flow cytometry and has broad applying prospect in phytoplankton study.It can be used for phytoplankton abundance,species composition analysis,size structure,biovolume estimation,HAB detection and morphological monitoring,phytoplankton cellular viability and metabolic activity measurement.This study mainly assess abundance and species composition of phytoplankton community,explore physiological parameters?viability and metabolic activity?of microalgae,and use different dyes to explore algicidal mechanism from the view of programmed cell death.Imaging flow cytometry technology has been applying in phytoplankton research from macro to micro scales,from field to laboratory at different levels,solving many technical problems.The main results are listed below:?1?The samples from the WenShan Lake was classified by FlowSight through the analysis of the distribution characteristics of the size and pigment content.It is concluded six populations,named R1,R2,R3,R4,R5 and R6.R1,R2,R5 and R6 are single morphology algae cell populations,which are small spherical cyanobacteria,small green algae,RhabdogloeaandPseudanabaena.R3isheterogeneouspopulation,including Merismopediaceae,Chroococcus,Planktolyngbya et al;R4 is fragments of algae.Different populations have different pigment content and size distribution.The cell density,pigment content and size distribution changed with the external environment.The experiment result can provide a application reference of imaging flow cytometry for phytoplankton monitoring in lake.?2?In the study of the growth process of the marine red alga Porphyridium cruentum,Porphyridium cruentum have different growth rate,particle size,chlorophyll a content,phycoerythrin content and exopolysaccharide production under different conditions.Seawater treatment and 10?mol·m^-2·s^-11 light intensity was favorable for the accumulation of chlorophyll a content,phycoerythrin content,but 80?mol·m^-2·s^-11 light intentsity can promote the accumulation of exopolysaccharide.This study provides a scientific basis for application of imaging flow cytometry in economic microalgae research.?3?In the study of programmed cell death?PCD?of the red tide dinoflagellate Alexandrium tamarense,imaging flow cytometry not only provides the marker parameters of all stages of PCD,but also presents each cell image,as well as the specific fluorescence location in the image.The results showed that algicidal bacterial supernatant could induce the PCD of Alexandrium tamarense.The highest apoptosis rate in 5%treatment was 56.80%,10%treatment was 63.60%.The process is likely to be regulated by Caspase 3-like.This study might provide theoretical foundation for finding new algicidal micobes and lay the foundation for application of imaging flow cytometry in PCD research of algae.