温度对等鞭金藻塔溪堤品系细胞密度和叶绿素荧光参数的影响

以等鞭金藻塔溪堤品系Isochrysis galbana（Tahitian strain）为试验材料,采用Water-PAM叶绿素荧光仪测定了该藻一次性培养过程中,不同温度（5～40℃）对其细胞密度、叶绿素相对含量以及叶绿素荧光参数（PSⅡ最大光能转化效率Fv/Fm、光化学淬灭qP）的影响。结果表明：温度对等鞭金藻塔溪堤品系的叶绿素相对含量和细胞密度均有显著影响（P〈0.05）;在本试验条件下,等鞭金藻塔溪堤品系在5、10℃和40℃下不能生长繁殖,该藻生长的适温为15～35℃,最适温度为20～30℃,各处理组的相对生长率从高到低依次为25℃〉20℃〉30℃〉35℃〉15℃;温度对等鞭金藻塔溪堤品系各叶绿素荧光参数也有显著影响（P〈0.05）,从接种后第1天到试验结束,5、10℃和40℃处理组藻类的主要荧光参数（Fv/Fm、qP）均显著低于其它处理组（P〈0.05）,其中25℃和30℃处理组藻类的主要荧光参数总体上低于15℃、20℃和35℃处理组,但高于其它处理组;试验结束时将5、10℃和40℃处理组的藻细胞重新置于25℃下继续培养6 d,5℃和40℃处理组藻类的主要荧光参数不能恢复,而10℃处理组藻类的主要荧光参数可恢复正常。相关性分析结果表明：荧光参数、叶绿素相对含量以及细胞密度与温度的相关性随着培养时间的变化而变化,叶绿素相对含量与细胞密度呈显著的正相关关系（P〈0.05）。

Effects of temperature on cell density and chlorophyll fluorescence parameters in Tahitian strain of alga Isochrysis galbana

The effects of temperatures（5-40 ℃） on cell density,relative chlorophyll content and chlorophyll fluorescence parameters（maximal effective quantum yield of PSⅡ in the dark,Fv/Fm;the photochemical quenching coefficient qP） were examined in Tahitian strain of Isochrysis galbana in batch cultures by Water-PAM chlorophyll fluorometer.One-way analysis of variance showed that temperature had significant effects on the cell density and relative chlorophyll content of the alga（Tahitian） during the experiment（P0.05）.Under this experimental condition,the proper growth temperature for the alga was 15-35 ℃,the optimal growth temperature of 20-30 ℃.The alga was found to cease growing and developing under 5,10 ℃ and 40 ℃.The relative growth ratio under different temperatures was arranged as 25 ℃20 ℃30 ℃35 ℃15 ℃.Temperature also had significant effects on the fluorescence parameters of the alga.The main parameters（Fv/Fm,qP） were significantly lower under 5,10 ℃ and 40 ℃ than those in other treatments from day 1 to the end of this experiment.At 25 ℃ and 30 ℃,however,the above main fluorescence parameters were generally lower than those at 15 ℃,20 ℃ and 35 ℃,but higher than others treatments.After cultured at 5,10 ℃ and 40 ℃ for ten days,the microalga was re-cultured in 25 ℃,100 μmol/（m2·s） conditions for 6 days,all the parameters in 5 ℃ and 40 ℃ treatment were not recovered absolutely,while those in 10 ℃ treatment were recovered to the normal level.The cell density,relative chlorophyll content and fluorescence parameters exhibited some correlations with temperatures,while the pattern and strength were varied with the temperature range and the culture period.Moreover,significant positive correlations between chlorophyll content and cell density were found during the experiment.