Mutant And Physiological Response Of Chlorella Induced By High Hydrostastic Pressure

Pressure is an important physical parameter; it has attracted more and more attention in biological sphere. The effect of high hydrostatic pressure on the morphology, growth and physiological characteristics of C.vulgaris were studied in this paper. The differences of physiological characteristics between C.vulgaris treated by hydrostatic pressure and the control were compared. The morphological changes of C.vulgaris were also carried out in this study. The main results are as follows:1. 80 MPa pressure seems not to be lethal to C.vulgaris, while 300 MPa pressure can result a significant death of C.vulgaris, a minority of C.vulgaris were surviving. 300 MPa pressure treated for an hour didn't contribute to its size, while several times of 300 MPa pressure treatment for 24 h is favored to the increase of C.vulgaris size, among which, 300 MPa pressure treated for 3 times has the most significant effect.2. The difference of dry weight, protein content and anti-oxidant enzyme activity between 80 MPa pressed C.vulgaris for different hours and the control were demonstrated. The highest cell dry weight was obtained when C.vulgaris was cultured after 12 hour's pressure treatment. Protein content increases with the decrease of dry weight. When C.vulgaris was preliminary pretreated by 300 MPa high hydrostatic pressure for an hour, then pressured by 80 MPa pressure for different hours, C.vulgaris which was treated for 2 hours has the maximal cell dry weight, treated with 6 hours has a maximal protein content. Under both condition, anti-oxidant enzyme activity decreases with the increase of pressed time.3. The Physiological characteristics of C.vulgaris treated by 300 MPa pressure for 24 hours with different times were compared with the control. The result indicated that the cultured C.vulgaris pressed by 300 MPa pressure for three times obtained the maximal growth rate and the highest cell dry weight, and cell generation time were shorten compared with the control. Besides that, the increased pigment content was measured in the three times pressed C.vulgaris cell, maybe the function of photosynthesis was strengthened.