Salt stress affects the growth and photosynthesis of Pyramidomonas sp. The researchers studied how different salt levels and exposure times impact the chlorophyll fluorescence of these microalgae. They found that the best salt concentration for Pyramidomonas sp. growth is 20. High salt levels decrease key fluorescence parameters and chlorophyll content, while non-photochemical quenching increases initially and then decreases. This study suggests that chlorophyll fluorescence can be used to assess salt resistance in microalgae.