Study On Biological Characteristics Of The Extreme Halotolerant Dunaliella Viridis

There are comparatively special active materials in the body of the extreme halotolerant Dunaliella viridis. D.viridis has extremely strong ability to resist against extreme environment. It has strong adaptable capacities to salinity, temperature, pH, light and druggery. It has potential development and application prospects.Several preliminary experiments were conducted to find the biological characteristics of the extreme halotolerant Dunaliella viridis living in the mud flat of Bohai Sea Gulf of China. Its contents included the study on tolerant characteristic to salinity, reproduction characteristic, growth characteristic, adaptable ability to environmental factor of high enriched brine's (including chemical factor, physics factor, biological factor) and the survival and development law of D.viridis in the mud flat of Bohai Sea Gulf was investigated.The results of the experiments show as follows:D.viridis can grow normally in certain salinity and adapts wide salinity range. The speed of adaptation to hypoosmotic shock is lower than to hyperosmotic shock. Suitable salinity of laboratory is 3°Be' ～8°Be' The maximum growth content and rate of D.viridis are obtained at the salinity 3°Be' and 5°Be' . The maximum growth content reaches 6000× 10⁴cells/ml. D.viridis usually becomes predominant species in high enriched brine (>15°Be' ) in the nature. The saturation brine helps to save the algae seed.D.viridis has 3 kinds of Growth mode: photosynthesis autotrophy, growth in the dark condition and mixed growth. Mixed growth is the best. D.viridis has nutrition, vegetative, sexual propagation, and a special fragmentized cell reproduction mode.D.viridis can grow under natural and common lights and survive in the dark environment. Its biological activation will depress under 24 hours strong illumination condition and growth will be accelerated if given properly certain darkness period. To promote its growth, fermented liquid of Artemia dry powder should be added to culture medium and the nutrition salt 2³g/L NaCk 1～2g/L MgCl₂ should be added to culture liquid in the middle periods and 5～6g/LNa₂SO₄ should be added in the later periods.