The Effects of Light Intensities,Temperatures,pH and Salinities on Photosynthesis of Chlorella
光照强度、温度、pH、盐度对小球藻（Chlorella）光合作用的影响

The effects of light intensities, temperatures, pH and salinities on photosynthesis of Chlorella sp. XQ-200419 and Chlorella marina NJ-016 were studied by measuring net photosyn-thetic O_2 evolution. For Chlorella sp. XQ-200419, the suitable light intensities ranged from 100 to 1600 μmol·m~(-2)·s~(-1) ,and the saturation light intensity is about 500 μmol·m~(-2)·s~(-1). The suitable temperatures ranged from 25℃ to 42. 5℃ ,with the optimal temperature of 37.5℃. The suitable pH values ranged from 6.5 to 9.0, and the optimum is pH 7.0. The net photosynthetic O_2 evolu-tion decreased a little while the salinity increased from 0 mol/L to 0.6 mol/L. For Chlorella mari-na NJ-016 ,the suitable light intensities ranged from 400 to 1600 μmol· m~(-2)·s~(-1) , and the satura-tion light intensity is about 1400 μmol·m~(-2)·s~(-1) The suitable temperatures ranged from 25℃ to 42. 5℃ ,with the optimal temperature of 37.5℃. The suitable pH values ranged from 5. 0 to 9.0, and the optimum is pH 8. 0. The net photosynthetic O_2 evolution increased obviously while the salinity increased from 0 mol/L to 0.6 mol/L. The results indicated the basic physiological and ecological characteristics of the two Chlorella species:adapting to relatively strong light intensi-ty, higher temperature, neutral to alkalescent conditions and higher salinity. However, there are some differences between these two species in their response to the change of environmental conditions. Compared with Chlorella sp. XQ-200419, Chlorella marina NJ-016 has higher satura-tion light intensity, and is able to adapt to much broader pH values. Besides, its photosynthesis is promoted by appropriate increase of salinity. It reveals that Chlorella marina NJ-016 might have more potential for fast growth in cultivation. The results are helpful for optimization of culture con-ditions for Chlorella,and also valuable for selection of Chlorella strains suitable for mass culture.