Study of photosynthetic system fluidity and long-term growth caused by salinity in cyanobacterium Fischerella sp. FS 18

The present study examined the responses of different parts of the photosynthetic system in Fischerella sp. FS 18 based on different concentrations (17, 80, and 160 mM) of sodium chloride and short time at regular intervals of 20, 40, and 60 min. The results revealed that salinity application (80 and 160 mM) after 20 minutes of inoculation significantly increased the yield of phycobilisome system. Increasing the time up to 40 minutes after inoculation could restore all parts of the photosynthetic system. Then, cyanobacteria can rearrange and activate photosystem II, phycobilisome, and light-collecting complex. However, the behavior of cyanobacteria at salinity of 160 and 80 mM were opposite at 20 and 60 min. Compared to the untreated sample, pretreatment application within less than one hour changed in terms of growth rate and attenuation at time intervals of 24 and 96 hours. The sample was capable of moderating the destructive effects of 160 mM for 20 min and 80 mM in 60 min treatments over 24 hours, which is incomplete. The growth rates up to 96 h in 80 mM for 20 min and 160 mM for 60 min treatments were higher than those without salinity. While the system changed its pattern after 24 hours, the initial pattern remained unaffected by time and salinity levels after this time. In general, simple salinity pretreatments and very short times increased the efficiency of energy transfer in photosystems and produced short and longterm energy and reduction, which could be considered as a major advantage for biotechnology of mass crops.