雨生红球藻细胞转化、虾青素积累与光照强度的关系及不同品系间的差异性

Effects of light intensity on cell transformation,astaxanthin accumulation in three strains of Haematococcus pluvialis and their difference

于2004年利用3个品系的雨生红球藻（H0、H2和H3）和以去除营养物质的藻液为实验对象，探讨了光强对细胞转化和虾青素积累的影响。结果表明，光照强度对红球藻虾青素积累和细胞转化有显著影响，并在品系间存在一定差异性。其中：品系H0在光强≤25000lx时虾青素积累量随光强的增加而增加，光强在20000—35000lx时虾青素积累量处于较高水平，而光照强度〉35000lx时，虾青素积累量随光强的升高而下降；H2品系在光强≤25000lx时虾青素积累量随光强的增加而增加，光强在25000lx左右时虾青素积累量较高，当光强≥35000lx时，虾青素积累大幅度下降；H3品系在≤35000lx时虾青素积累量随光强的升高而增加，20000—45000lx为虾青素积累较适宜的光强，高于45000lx时虾青素积累量则明显下降。进一步分析得出，弱光导致红球藻虾青素含量较低是光照强度不足、细胞内虾青素含量少的结果，而强光下虾青素含量下降则是细胞受到损伤、细胞数量减少导致的。对比研究发现：在较低光强下（20000～250001x）H2单个细胞内虾青素积累量略低于H0，但其积累虾青素总量却最高，这是由于此时H2不动细胞增长速率比其它品系高造成的，不过适宜H2积累虾青素的光照范围最窄，它对高光强的耐爱性也最差；而H3在较低光强下虾青素积累总量及单个细胞内的积累速率均最低，但是它的适宜光照范围最宽，即对高光强的耐受性最强，在较大的光强波动范围内都可以保证较高的安全转化量，这就使得它在较高的光强下虽然单个细胞积累虾青素的速率仍然最低，积累总量反而显著高于其它两个品系。

Effects of light intensities on cell transformation, astaxanthin accumulation in three stains of Haematococcus pluvialis （H0,H2 and H3） were studied in 2004 by using nutrients eliminated culture. Results showed a distinctive influence of light intensity on astaxanthin accumulation and cell transformation from motile cells to non-motile cells. Astaxanthin concentration in H0 increased with the enhancement of light intensity in the range lower than 25 000 lx. It remained at a high level under the light intensity between 20 000 and 35 000 lx, then started to decrease severely when the light intensity was over 35 000 lx. H2 showed similar astaxanthin changes to H0 except for that maximal astaxanthin was obtained at 35 000 lx. Regarding to H3, an increase of astaxanthin accumulation was accompanied with an improvement of light intensity in the range below 35 000 lx. Light intensity between 20 000 lx 45 000 lx was conducive to astaxanthin accumualation then led to a decrease of astaxanthin if further increase light radiation. The reasons causing astaxanthin accumulation decrease in low dim light differed from that at high light radiation. The former was mainly led by the decrease of astaxanthin per c.ell, and the latter was a result of light damage and reduction of safety cell transformation. Comparison of three strains abilities of astaxanthin accumulation found that H2 showed the highest amount of astaxanthin quantity under light intensities between 20 000 lx and 25 000 lx due to its fast non-motile cell growth rate. Meanwhile, H2 had the narrowest favorable light intensity and poorest tolerance to strong light among the three strains. On the contrast, H3 showed a high rate of cell transformation from motile cells to non-motile cells and good output of astaxanthin because of its wide range of suitable light intensity and high tolerance to strong light.