外源一氧化氮调控三角褐指藻响应氮胁迫的作用研究

Regulation of Exogenous NO on Response of Phaeodactylum tricornutum to Nitrogen Stress

为探究外源一氧化氮(Nitric Oxide,NO)对三角褐指藻(Phaeodactylum tricornutum)响应氮胁迫的作用,本研究通过添加外源NO供体硝普钠(Sodium Nitroprusside,SNP)及NO清除剂[2-(4-carboxyphenyl)-4,4,5,5-teramethylimidazoline-1-oxyl-3-oxide,cPTIO],探讨外源NO对氮胁迫条件下的三角褐指藻细胞密度、叶绿素含量、叶绿素荧光参数、岩藻黄素含量、油脂相对含量等的影响。结果表明,缺氮会抑制三角褐指藻细胞的生长,显著降低叶绿素a(chla)含量与光合效率,降低岩藻黄素含量,增加脂质合成。与氮正常情况下相比,在缺氮条件下添加200μmol/L SNP可在一定程度上缓解缺氮对三角褐指藻生长、叶绿素含量、光合效率与岩藻黄素积累的抑制,并能显著促进油脂的积累。在缺氮条件下添加50μmol/L cPTIO对三角褐指藻的生长、叶绿素含量、光合效率及物质积累影响不大。本研究可为探明外源NO调控三角褐指藻响应氮胁迫的作用机制提供基础数据,也为进一步提高逆境条件下三角褐指藻的生物量及促进成分积累量提供参考依据。

In order to explore the effect of exogenous Nitric Oxide(NO)on the response of Phaeodactylum tricornutum to nitrogen stress,in this study,exogenous NO donor Sodium Nitroprusside(SNP)and NO scavenger 2-(4-carboxyphenyl)-4,4,5,5-teramethylimidazoline-1-oxyl-3-oxide(cPTIO)were added to investigate the effects of exogenous NO on cell density,chlorophyll content,chlorophyll fluorescence parameters,fucoxanthin content and lipid relative content of P.tricornutum under nitrogen stress.The results showed that the deficiency of nitrogen would inhibit the growth of P.tricornutum cells,significantly reduced chlorophyll a(chla)content and photosynthetic efficiency,reduced fucoxanthin content,and increased lipid synthesis.Compared with normal nitrogen,the addition of 200μmol/L SNP under nitrogen deficiency could alleviate the inhibition of nitrogen deficiency on the growth,chlorophyll content,photosynthetic efficiency and fucoxanthin accumulation of P.tricornutum to a certain extent,and significantly promote the accumulation of oil.The addition of 50μmol/L cPTIO under nitrogen deficiency had little effect on the growth,chlorophyll content,photosynthetic efficiency and material accumulation of P.tricornutum.This study can provide basic data for exploring the mechanism of exogenous NO regulating the response of P.tricornutum to nitrogen stress,and also provide reference for further improving the biomass and promoting component accumulation of P.tricornutum under stress conditions.