THE APPLICATION OF GENETICALLY MANIPULATED CYANOBACTERIAL STRAINS IN THE STUDY OF GLYCEROLIPID UNSATURATION OF PHOTOSYNTHETIC MEMBRANES IN THE TOLERANCE OF PHOTOSYNTHETIC MACHINERY TO TEMPERATURE STRESSES

Cyanobacteria provide a simple experimental model system of the higher -plant chloroplast. Both perform oxygenic photosynthesis and their pho tosynthesis membranes contain very similar lipids. Some cyanobacterial strains are transformable and this opens up to the possibility of man ipulating the lipid background of photosynthetic machinery independent ly from other membrane constituents. Using chilling-sensitive and chil ling-tolerant strains, the importance of polyunsaturated glycerolipids in temperature adaptive responses and in tolerance to temperature str esses is demonstrated. The involvement of dienoic fatty acids in low-t emperature tolerance has been suggested. The role of 18.2 fatty acids in the recovery process from low-temperature photoinhibition has also been emphasized. However, the determinative role of saturated and poly unsaturated fatty acids in high-temperature tolerance has not been pro ved.