Allelopathic effects of phenolic compounds released by <i>Vallisneria spiralis</i> on <i>Microcystis aeruginosa</i>

Abstract

采用广谱性固相萃取小柱富集以10g(FW)/L的密度培养三天后的苦草(Vallisneria spiralis)种植水, 不同溶剂洗脱得到的各组分对铜绿微囊藻(Microcystis aeruginosa)的生长表现出不同程度的抑制, 其中甲醇洗脱组分抑藻活性最强.去除该组分中的酚酸后, 其抑藻活性下降了22.8%, 表明酚酸参与到苦草的化感抑藻作用中.甲醇组分通过液液萃取进一步分离, 得到的乙酸乙酯组分进行GC-MS分析, 从中检测到苯甲酸、对羟基苯甲酸、对羟基苯乙酸、邻苯二甲酸、对羟基苯丙酸、香草酸、原儿茶酸、阿魏酸和咖啡酸等九种酚酸.酚酸抑藻测试的结果显示其抑藻活性与本身的结构有关, 不同酚酸以毒性效应比例多维混合表现出加和抑藻效应, 且随着混合种数的增多, 酚酸的加和效应增强.以上结果显示苦草可以释放酚酸, 抑制铜绿微囊藻的生长, 多种化感物质的联合作用可能是水生态系统中沉水植物抑制蓝藻生长的一个重要机制。;Culture solutions of the submerged freshwater macrophyte Vallisneria spiralis, incubated at 10 g(FW)/L for three days, were extracted by solid phase extraction(SPE)with broad spectrum cartridges, and eluted with different solvents.The acquired fractions exerted various inhibitory effects on the growth of Microcystis aeruginosa, and the methanol-eluted fraction showed the strongest effect.After removing the phenolic compounds from the fraction, the inhibition rate was decreased by 22.8%, indicating that the phenolic compounds controlled the algal growth inhibition of V.spiralis.Moreover, the methanol-eluted fraction was further separated by liquid extraction(LLE), and the acquired ethyl acetate fraction was analyzed by gas chromatograph-mass spectrometry (GC-MS).Nine phenolic compounds were identified:benzoic acid, p-hydroxybenzoic acid, p-hydroxyphenylacetic acid, phthalic acid, 3-(4-hydroxyphenyl)propionic acid, vanillic acid, protocatechuic acid, ferulic acid and caffeic acid.The algal inhibition test showed that the antialgal effects of the phenolic compounds were influenced by their structures.The multiple phenolic com-pounds, mixed at a ratio corresponding to their single toxicity, showed additive effects in most cases, which became much obvious with the increase of phenolic classes in the mixture.These results indicate that V.spiralis could release phenolic compounds to in-hibit the growth of M.aeruginosa, and the joint action of multiple allelochemicals may be an important allelopathic factor of sub-merged macrophytes to inhibit the growth of noxious cyanobacteria in natural aquatic ecosystems.