硅浓度对筒柱藻B169生长、叶绿素荧光参数、总脂含量及脂肪酸组成的影响

Effects of Silicon Concentrations on the Growth,Chlorophyll Fluorescence Parameters,Total Lipid Content and Fatty Acid Compositions of Cylindrotheca sp.B169

本文以底栖硅藻筒柱藻(Cylindrotheca sp.)为实验材料,研究了一次性培养过程中,不同硅浓度即:0mg/L(Si0)、8.35mg/L(Si1)、33.4mg/L(Si2)、133.6mg/L(Si3)、534.4mg/L(Si4)和1068.8mg/L(Si5)对藻细胞密度、叶绿素荧光参数、叶绿素含量、总脂含量及脂肪酸组成的影响。结果表明:第5~9d,筒柱藻的细胞密度随硅浓度的增加而增加,硅浓度较高的Si3、Si4和Si5处理组的细胞密度显著高于硅浓度较低的Si0、Si1和Si2处理组的细胞密度。第1~9d,Si5处理组的荧光参数F_v/F_m(PSII的最大光能转换效率)和F_v/F_o(PSII的潜在活性)均显著低于其它处理组。第3~6d,Si3处理组的上述荧光参数均显著高于其它处理组。第1~7d,Si4和Si5处理组的荧光参数φPSII(PSII的实际光能转化效率)和rETR(相对电子传递效率)均显著低于其它处理组,其中Si5处理组的上述荧光参数最低,其次是Si4处理组。筒柱藻的叶绿素含量随着硅浓度的增加而增加,到Si3处理组叶绿素含量达最高值,之后叶绿素含量下降,Si3处理组的叶绿素含量最高,Si0处理组的叶绿素含量最低。筒柱藻的总脂含量随硅浓度的增加而降低,Si0处理组的总脂含量最高,Si5处理组的总脂含量最低。筒柱藻的主要脂肪酸是1 4:0(5.1 5~8.7l%)、16:0(22.40~42.27%)、1 6:1n-7(3l.40~33.12%)、16:3n-4(1.89~8.45%)、20:4n-6(5.95~11.39%)和20:5n-3(EPA)(3.47~8.07%)。饱和脂肪酸含量随着硅浓度的增加而降低,多不饱和脂肪酸含量随着硅浓度的增加而增加,硅浓度对单不饱和脂肪酸的影响差异不显著。经济价值较大的20:4n-6和20:5n-3含量均在Si3和Si4处理组达到最高值。

In this experiment, the chlorophyll fluorescence parameters, cell densities, chlorophyll con- tents, total lipid contents and fatty acid compositions of the benthic diatom namely Cylindrotheca sp. B169 were studied under different silicon concentrations ： 0mg/L （Si0）, 8. 35mg/L （Sil）, 33. 4mg/L （Si2）, 133.6mg/L（Si3）, 534.4mg/L（Si4）, and 1068.8mg/L（Si5）. The results showed that the cell densities of Cylindrotheca sp. increased with increasing silicon concentrations from day 4 to day 9, with those in the higher silicon concentrations （Si3, Si4, and Si5） significantly higher than those in the low- er silicon concentrations （Si0, Sil, and Si2）. The parameters F1/F2, （the maximal photochemical effi- ciency of PSII） and FJFo （potential activity of PSII） in SiS treatment were significantly lower than those in other treatments from day 1 to day 9, whereas in Si3 treatment, the above two parameters were significantly higher than those observed in other treatments from day 3 to day 6. As to the param- eters q^PSII （the actual photochemical efficiency of PSII） and rETR （the relative electron transport rate）, the values in Si4 and Si5 treatments were significantly lower than those in other treatments from day 1 to day 7, with the lowest value occurring in SiS treatment. The chlorophyll contents of Cylin- drotheca sp. first increased then decreased with increasing silicon concentrations, with the maximum value in Si3 treatment and minimum value in Si0 treatments. The total lipid contents decreased with in- creasing silicon concentrations, with the largest value shown by Si0 treatment and the lowest value by SiS treatment. The major fatty acids under different silicon concentrations were 14 ： 0（5.15~8.71%）, 16：0（22.40~42.27%）, 16 ： ln-7（31.40~33. 12%）, 16 ： 3n-4（1.89~8.45%）, 20 ： 4n-6（5.95~ 11.39%）, and 20 ： 5n-3（EPA）（3.47~8.07~）. The saturated fatty acids （SFA） decreased while the polyunsaturated fatty acids （PUFA） increased with the increasing silicon concentrations, whereas there was no significant variation in the monounsaturated fatty acids （MUFA） related to silicon concentra- tions. The maximum contents of 20 ： 4n-6 and 20 ： 5n-3 which had more economic values were all re- corded in Si3 and Si4 treatments.