中文摘要：

采用生物测试法,以九龙江口的优势藻种新月菱形藻（Nitzschia closterium）为受体研究了秋茄[Kandelia obovata（S.L.）Yong]凋落叶的抑藻作用,并利用高效液相色谱法对其分解过程中的酚酸化感物质进行了分析.通过酚酸对新月菱形藻密度以及生理生化的影响,探讨了秋茄凋落叶对底栖硅藻的化感效应,丰富了安全、有效防治藻类的爆发的理论依据与实践经验,为揭示红树植物与林内微藻间相互关系提供新的科学依据.对新月菱形藻密度测定的研究发现：未分解秋茄凋落叶水提液的抑藻作用存在浓度效应,随着水提液浓度的增加,抑制作用增强;半分解秋茄凋落叶（半分解期t50=42d）水提液对新月菱形藻的生长则无明显影响.高效液相色谱检测结果确定秋茄凋落叶中存在对羟基苯甲酸、香草酸、丁香酸、绿原酸和咖啡酸;随着凋落叶的分解,酚酸的含量下降.标准酚酸物质及混合酸均对新月菱形藻产生化感抑制作用,且随着浓度增大,抑制作用增强.这表明在红树林根际-沉积物-水环境界面上,红树植物凋落物对微藻的繁殖起到了一定的调控作用,而酚酸是其中起重要作用的一类物质.

英文摘要：

In order to explore the allelopathy of mangrove leaf litters,Nitzschia closterium was used to examine the allelopathy effects of Kandelia obovata（S.L.）Yong leaf litters on algagrowth.The results showed that water extract of undecomposed K.obovataleaf litters significantly inhibited the growth of N.closterium,the inhibition effects increased at higher concentrations of leaf litters.Water extract of half-decomposed（t50=42d）K.obovataleaf litters had no significant effect on the growth of N.closterium.Hydroxybenzoate,vanilloid,clove acid,chlorogenic acid and caffeic acid were determined by high performance liquid chromatography in K.obovata leaf litters,and the concentration of these components decreased with the decomposition of leaf litters.Our data showed that these phenolic substances had significant allelopathy effect on N.closterium.Therefore,mangrove plants controlled the growth of microalgae in the rhizosphere-sediment-water interface,and allelochemicals was an important reason.This study enriched the theory and practical experience in preventing algal outbreaks safely and effectively,providing a new basis for revealing the relationship between mangroves and microalgae.