IAA对球等鞭金藻和棕鞭藻生长及总脂含量的影响

摘要

Effect of IAA at 0.1～5 and 0.1～3 mg/L on the maximal photochemical efficiency of PSⅡ (Fv/Fm),relative electron transport rate (rETR),photochemical quenching (qP),cell density,chlorophyll content,total lipid content and fatty acid composition of Isochrysis galbana and Ochromonas neopolitana was investigated,respectively.The results showed that the optimal IAA concentration for the photosynthesis and growth of I.galbana and O.neopolitana was 0.1 and 0.25 mg/L,respectively,at which,Fv/Fm,rETR,qP,cell density and chlorophyll content of two microalgae were all higher than those of control and those at other concentrations.Compared with control,the cell density and chlorophyll content of I.galbana increased by 32.6％ and 37.1％,respectively.Its total lipid content was higher than that at other concentrations but similar to that of control.For O.neopolitana,the cell density and chlorophyll content at 0.25 mg/L increased by 48.7％ and 34.4％,respectively,however the high-est total lipid content of this alga was detected at 0.5 mg/L,which was similar to that at 0.25 mg/L.For fatty acid composition,the 0.1 mg/L IAA enhanced the synthesis of DHA,but not other fatty acid components (14:0,16:0,16:1n-7,18:1n-9).The 0.25 mg/L IAA enhanced the synthesis of both DHA and other polyunsaturated fatty acids of O.neopolitana.Our findings indicated that the optimal IAA concentration for the growth and oil accumulation of I.galbana and O.neopolitana was 0.1 mg/L and 0.25 mg/L,respectively,which provided the theoretic basis for large scale cultivation of two microalgae.%本文研究了0.1～5 mg/L的-3吲哚乙酸(IAA)对球等鞭金藻(Isochrysis galbana)和0.1～3 mg/L的IAA对棕鞭藻(Ochromonas neopolitana)的叶绿素荧光参数(PSⅡ最大光能转化效率Fv/Fm、相对电子传递速率rETR、光化学淬灭qP)、细胞密度、叶绿素含量、总脂含量及脂肪酸组成的影响.研究表明,球等鞭金藻和棕鞭藻进行光合作用和生长的最适IAA浓度分别为0.1和0.25 mg/L.此条件下,2株藻的Fv/Fm、rETR、qP、细胞密度和叶绿素含量均显著高于对照组和其它处理组.其中,球等鞭金藻的细胞密度和叶绿素含量分别比对照组增加了32.6％和37.1％,总脂含量显著高于其它处理组,但与对照组差异不显著(P＞0.05);棕鞭藻的细胞密度和叶绿素含量在IAA浓度为0.25 mg/L时分别比对照组增加了48.7％和34.4％,总脂含量在IAA浓度为0.5mg/L时显著高于对照组和其它处理组,但与0.25 mg/L处理组差异不显著(P＞0.05).0.1 mg/L的IAA浓度对球等鞭金藻DHA(二十二碳六烯酸)的合成有促进作用,但对其它各脂肪酸(14:0、16:0、16:1n-7和18:1n-9)含量均无显著影响;0.25 mg/L的IAA浓度促进了棕鞭藻DHA和多不饱和脂肪酸的合成.研究结果表明,球等鞭金藻和棕鞭藻进行生长和油脂积累的最适IAA浓度分别为0.1和0.25mg/L,此结果为2株藻的大规模培养提供了理论依据.