Discovery Of Endosymbiotic Cyanobacteria In Green Alga Haematococcus Pluvialis And Preliminary Study On The Physio-Biochemical Characteristics

Cyanobacterial symbionts in the Haematococcus pluvialis were discovered during the reproductive process of its host cells for the first time. It is related to chroococcus by morphological analyzing, and the physio-biochemical characteristics were studied preliminaryly. In the process of orgnism evolution, the cyanobacteria played the role which linked the preceding with the fllowing, and the endosymbiotic cyanobacterial made great sense in the evolution of aerobic Eukarya and the origin of chloroplasts. We have separated the cyanobacteria from Haematococcus pluvialis successfully and studied on its physio-biochemical characteristics including cell morphological, growth cycle, pigment content, spectrum cheracters etc. The results are as follows:1. After the classic method of morphological classification which was carried out by the optical microscope,observing the characteristics of the shape, size, color, the mode of splitting, we have determined that it belonged to Chroococcus initially, and extrmly liked chroococcus minutus.2. The endogenetic alga was hypersensitive to light intensity in vitro, that is, when cultured under LL conditon and ML condtion separatetly, there were significant difference in physiological-biochemical characters:(1).Cell morphological.?When?cultured under LL condition, 2-4 cells clung together and most of the cells are in the state of fissive; 7-11μm in length and 4-8μm in width for mother cells that in diving, and 4-5μm in diameter for daughter cells, hardly see less than 4μm.?However, when cultured under ML condition, fewer cells that are dividing were observed, that is, most cells existed in monocellular; the cell size at the range of 3-7μm.(2).Cell cycle. Under LL condition, the lag-period was both about 2 days, and the logarithmic growth phase was about 25 days, and 30 days later, the cells into stabilizers; While when cultured under ML condition, There was almost no postponing stage in its growth life, and the logarithmic growth phase was a relatively long time (about 30 days); and the stationary phase would Maintain a long time (about 60 days) before it into decay stage.(3).Pigment contents and spectrum characters. The pigments bound to thylakoid membranes of cyanobacteria are mainly chlorophyll a, carotenoid, C-PC and APC etc. Chlorophyll a is the main light-harvesting pigment cultured under ML condition, however, the content of C-phycocyanin was higher than chlorophyll a and being the main light-harvesting pigment.3. In our study, the cyanobacteria discovered from Haematococcus pluvialis would never reinstate to the physiological state as under 800lx again when put them back to the former environment. This is never reported before.