氮磷饥饿时间对筒柱藻生长及总脂含量的影响

摘要

以筒柱藻为试验材料,研究了其在一次性培养过程中,氮磷营养盐饥饿时间(0、1、2、4、6、8 d)对该藻叶绿素荧光参数、细胞密度、叶绿素含量、干质量、总脂含量及脂肪酸组成的影响.结果表明,光系统Ⅱ最大光化学量子产量、光化学淬灭、最大光合作用速率、快速光曲线的初始斜率和半饱和光照度均随氮、磷饥饿时间的延长而显著下降,说明该藻的光合作用受到了抑制.细胞密度分别在氮饥饿的第6 d和磷饥饿的第8 d达到最大值,但总体升高幅度不大.氮饥饿和磷饥饿条件下,干质量和总脂含量均随氮磷饥饿时间的延长逐渐升高,总脂含量分别在氮饥饿的第8 d(35.3%)和磷饥饿的第6 d(28.9%)达到最大值.氮磷饥饿时间对筒柱藻的脂肪酸组成也有显著影响,16:0和总饱和脂肪酸含量随氮磷饥饿时间的延长逐渐升高,20:4n-6、20:5n-3和总多不饱和脂肪酸含量则随氮磷饥饿时间的延长逐渐降低,16:1n-7和总单不饱和脂肪酸含量随氮饥饿时间的延长逐渐升高,而磷饥饿时间对16:1n-7和总单不饱和脂肪酸含量变化影响不显著.上述指标随氮磷饥饿时间的变化趋势可为筒柱藻的大规模培养及开发利用提供参考.%In this experiment, the chlorophyll fluorescence parameters, cell densities, chlorophyll contents, dry weights, total lipid contents and fatty acid compositions of marine diatom Cylindrotheca sp.B200 were studied under different nitrogen and phosphorus starvation time (0 d, 1 d, 2 d, 4 d, 6 d, and 8 d).The results showed that the maximal photochemical efficiency of PSⅡ, photochemical quenching, non-photochemical quenching, the maximum efficiency of photosynthesis, initial slope of rapid light curve and the half saturation light intensity were all decreased significantly with the increase in nitrogen and phosphorus starvation time, indicating that the photosynthesis of marine diatom was inhibited.Under nitrogen and phosphorus starvation conditions, the maximal values of the cell density were recorded at the 6th day and the 8th day, respectively, but increased slightly.The dry weight and total lipid content were increased gradually with the increasing nitrogen and phosphorus starvation time, with the maximum total lipid occurring on the day 8 (35.3%) in nitrogen starvation treatment and that on day 6 in phosphorus starvation treatment (28.9%).Nitrogen and phosphorus starvation time also had significant effects on the fatty acid compositions of the marine diatom.The contents of 16:0 and the total saturated fatty acids were increased while those of 20:4n-6, 20:5n-3 and the total polyunsaturated fatty acids decreased as nitrogen and phosphorus starvation time increased.For the 16:1n-7 and the total monounsaturated fatty acids, the values increased with the increasing nitrogen starvation time, whereas there was no significant variation in the above fatty acids related to the phosphorus starvation time.The trend of these indicators changing with nitrogen and phosphorus starvation time provides the reference for the large-scale cultivation and exploitation of marine diatom.