通过测定和比较聚球藻（Synechococcus sp. PCC7942）的细胞密度、细胞形态、叶绿素a含量、部分叶绿素荧光参数和抗氧化酶活性，研究苯甲酸、水杨酸和阿魏酸对聚球藻的生长抑制效应及机制。结果显示：与对照（不添加酚酸类化感物质）相比，苯甲酸和阿魏酸对聚球藻的生长、叶绿素a含量和初始荧光（Fo）呈低促高抑的效应；水杨酸对聚球藻的生长、叶绿素a含量和Fo值呈抑制效应，且抑制效果总体上随其浓度的升高而增强；3种酚酸类化感物质对聚球藻的PSⅡ最大光化学效率（Fv/Fm）呈抑制效应，且Fv/Fm值随着三者浓度的升高而降低。40 mg·L^-1苯甲酸、35 mg·L^-1水杨酸和60 mg·L^-1阿魏酸处理9 d，聚球藻生长的抑制率分别高达86.80%、85.39%和79.35%。3种酚酸类化感物质的高浓度处理造成聚球藻细胞膜破裂，内容物大量外泄，出现聚团和板结现象。随着苯甲酸浓度的升高，聚球藻的超氧化物歧化酶（SOD）活性逐渐降低，过氧化物酶（POD）和过氧化氢酶（CAT）活性逐渐升高；SOD、POD和CAT活性随着水杨酸浓度的升高而降低，随着阿魏酸浓度的升高而升高。总体上看，3种酚酸类化感物质对聚球藻的生长抑制效应由高至低依次为水杨酸、苯甲酸、阿魏酸。酚酸类化感物质不仅通过阻碍聚球藻叶绿素a合成和抑制PSⅡ活性来抑制细胞生长，而且通过减少细胞分裂、破坏细胞膜、增加胞外絮状分泌物和影响抗氧化酶活性等途径抑制细胞繁殖或导致细胞死亡。

Inhibitory effects and mechanisms of benzoic acid， salicylic acid， and ferulic acid on growth of synechococcus （Synechococcus sp. PCC7942） were investigated by measuring and comparing cell density， cell morphology， chlorophyll a content， some chlorophyll fluorescence parameters， and antioxidant enzyme activities of Synechococcus sp. PCC7942. The results show that compared with the control （not adding phenolic acid allelochemicals）， low and high concentrations of benzoic acid and ferulic acid have promoting and inhibitory effects on the growth， chlorophyll a content， and initial fluorescence （Fo） of Synechococcus sp. PCC7942 respectively； salicylic acid has inhibitory effects on the growth， chlorophyll a content， and Fo value of Synechococcus sp. PCC7942， and the inhibitory effects are elevated with the increase of its concentration in general； 3 phenolic acid allelochemicals have inhibitory effects on the maximum photochemical efficiency of PSⅡ （Fv/Fm） of Synechococcus sp. PCC7942， and the Fv/Fm values decrease with the increase of their concentrations. After treated with 40 mg·L^-1 benzoic acid， 35 mg·L^-1 salicylic acid， and 60 mg·L^-1 ferulic acid for 9 d， the inhibition rates of growth of Synechococcus sp. PCC7942 reach 86.80%， 85.39%， and 79.35%， respectively. Treatments with high concentrations of 3 phenolic acid allelochemicals cause membranolysis and massive leakage of content of Synechococcus sp. PCC7942， lead to agglomeration and compaction. With the increase of benzoic acid concentration， superoxide dismutase （SOD） activity in Synechococcus sp. PCC7942 gradually decreases， and peroxidase （POD） and catalase （CAT） activities increase gradually； SOD， POD， and CAT activities decrease with the increase of salicylic acid concentration and increase with the increase of ferulic acid concentration. On the whole， the inhibitory effects of 3 phenolic acid allelochemicals on growth of Synechococcus sp. PCC7942 from high to low are salicylic acid， benzoic acid， ferulic acid. Phenolic acid allelochemicals not only inhibit the cell growth of Synechococcus sp. PCC7942 via interfering synthesis of chlorophyll a and inhibiting activity of PSⅡ， but also inhibit cell reproduction or cause their death via reducing cell division， damaging cell membrane， increasing extracellular flocculent secretion， and affecting antioxidant enzyme activities， etc.