海洋微藻释放的化感物质及其作用机理研究

Allelopathy, one of the important factors for phytoplankton community evolution that plays a significant role in the occurrence, maintenance and succession of red tides. Allelochemicals is the media that constrains or promotes the coexisting species. However, the isolation and identification of allelochemical almost remain unknown which only a few regulation effects of allelopathy in the community of phytoplankton have been studied. In this subject, typical red tide species in adjacent China sea, such as Prorocentrum donghaiense, Skeletonema costatum, Heterosigma akashiwo,etc. were selected as target algaes. Laboratory culture was conducted to investigate allelopathic effect between target algaes and tested algaes. A series of experiments were also carried out to study the properties of allelochemical. Ultimately, a set of methods to extract, isolate and identify the allelochemical were established. On that basis, allelochemical was obtained from the filtrate of target algae and then the examination of the biological effects of the allelochemical was conducted to assure the concentration range that allelochemical play roles in the culture. Moreover, the action mechanism of allelochemicals at the cellular level were investigated that would help better understand the role of allelopathy of microalgae in community succession from the perspective of chemical ecology. The study is helpful to elucidate the internal mechanism of microalgae community succession, reveal the mechanism of micro-algae dominant species elimination and assess the role of allelopathy in the succession of dominant species of phytoplankton.

化感作用是浮游植物群落发展演变的重要因素之一，对于赤潮的发生、维持和演替具有重要的作用。化感物质是浮游植物产生化感作用的媒介，然而目前关于化感物质的分离鉴定以及化感作用对海洋浮游植物群落调控影响的研究还很少。本课题从中国近海典型的赤潮微藻中筛选出目标藻，如东海原甲藻、中肋骨条藻、赤潮异弯藻等，应用实验室培养的方法考察它们对其他受试浮游藻类的化感作用，探讨释放的化感物质的理化性质，建立系统的提取、分离、鉴定水体中化感物质的方法，获得目标藻滤液中的化感物质，并进行生物效应检验以确定特定化感物质发生作用的浓度范围。在此基础上，从细胞水平上阐明化感物质的作用机理，从化学生态学角度更加深入认识微藻的化感作用在群落演替中的作用。这为阐明微藻群落演替的内因，揭示微藻优势种生消机制，评估化感效应在浮游植物优势种演替中的作用具有重要的意义。

化感作用是海洋浮游植物群落发展演变的重要因素之一，对于赤潮的发生、维持和演替具有重要的调节作用，然而目前关于化感物质的分离鉴定以及化感作用对海洋浮游植物群落调控影响的研究还很少。本课题从中国近海典型的赤潮微藻中筛选出目标藻，如东海原甲藻、中肋骨条藻、米氏凯伦藻等，应用实验室培养的方法探究它们对其他受试浮游藻类的化感作用，探讨释放的化感物质的理化性质，建立系统的提取、分离、鉴定水体中化感物质的方法，获得目标藻滤液中的化感物质，从细胞水平上阐明化感物质的作用机理，从而深入认识微藻的化感作用在群落演替中的作用。这为阐明微藻群落演替的内因，揭示微藻优势种生消机制，评估化感效应在浮游植物优势种演替中的作用具有重要的意义。.本项目全面、深入、系统地研究了我国近海典型海洋微藻间的化感作用，通过4年的研究工作，取得的以下重要的创新性的研究成果： .1）验证了11种海洋微藻间的化感作用，并筛选出5种提取化感物质的合适藻种；.2）通过液液提取/固相萃取、柱层析以及HPLC等提取分离方法，FT-IR、HPLC、HPLC-MS等检测方法，优化了5种微藻化感物质的提取和分离方法，建立了一套化感物质提取分离体系，并运用UHPLC-TOF-MS建立了可同时靶向筛查60种已知低极性化感物质的方法；.3）从细胞和分子水平（酯酶、膜电位、细胞形态、光合作用、抗氧化活性以及基因组转录表达等）上阐明了3种海洋微藻抑制浮游植物生长的机理，评估了海洋微藻间的化感作用在种间竞争及种群演替中的作用。.项目完成科技论文15篇，培养博士、硕士研究生7名，完成了项目目标和任务。