芦苇腐解土中酚酸类化感物质的水分响应特性研究

芦苇和虉草均具有较强的去污能力,常作为湿地植物配置于同一人工湿地进行污水处理。芦苇作为一种强化感植物对虉草具有较强的化感作用,在自然湿地和人工湿地中均会出现芦苇代替虉草的现象,且这一现象的发生与土壤含水量存在一定联系,此外,芦苇腐解土对虉草的化感抑制效应与腐解土中总酚酸的量密切相关。为了研究芦苇腐解土中主要酚酸类物质的水分响应特性,筛选出其中对水分响应较为明显的酚酸物质种类,该研究采用高效液相色谱法,通过芦苇枯落物腐解土的制备,对不同水分环境下芦苇腐解土中酚酸类物质进行了分离和鉴定。结果表明:芦苇腐解土中可分离出没食子酸、香豆酸、香草酸、丁香酸、对香豆酸、阿魏酸、水杨酸和苯甲酸等8种酚酸类物质,其中香豆酸、苯甲酸和阿魏酸等3种酚酸类物质含量较高。分离出的8种酚酸类物质的含量与腐解土的相对含水量均呈显著线性负相关关系,即随着腐解土相对含水量的上升,酚酸类物质的含量均呈现下降趋势,且各种酚酸类物质对水分的响应趋势均可用线性方程较好地拟合。其中,香豆酸、没食子酸和阿魏酸对芦苇腐解土的水分响应最为明显。因此,可将香豆酸、没食子酸和阿魏酸作为主要调控目标,通过调控湿地土壤中水分含量,削弱芦苇对虉草的化感抑制效应,从而维持人工湿地中虉草芦苇群落的长期稳定共存。

Response characteristics of phenolic acids substances to soil moisture in Phragmites australis decomposing soil

Both Phragmites australis and Phalaris arundinacea have strong detergency capabilities and are often deployed as wetland plants in the same constructed wetland for sewage treatment. As a kind of allelopathic plant, Phragmites australis has strong allelopathy effects on Phalaris arundinacea and P. arundinacea would be instead of Phragmites australis in both natural wetland and constructed wetland. This phenomenon is related to the soil moisture content and the allelopathic inhibitory effect of P. australis decomposing soil on Phalaris arundinacea is closely related to the amount of total phenolic acids in the decomposing soil. Therefore, high performance liquid chromatography(HPLC)was used to separate and identify phenolic acids substances in Phragmites australis decomposing soil under different moisture content conditions to select the types of phenolic acids that the most obvious responded to moisture in this paper. The competition balance between P. australis and Phalaris arundinacea can be achieved through the regulation of wetland soil moisture, therefore, the long-term stable coexistence of the two species in the constructed wetland can be achieved. The results showed that eight kinds of phenolic acids were separated and identified, which were gallic acid, coumaric acid, vanillic acid, syringic acid, p-coumaric acid, ferulic acid, salicylic acid, and benzoic acid, respectively. The contents of three kinds of phenolic acids of coumaric acid, benzoic acid, and ferulic acid were higher among eight kinds of identified phenolic acids. There was a significant linear negative correlation between content of every identified phenolic acid and the relative moisture content of the Phragmites australis decomposing soil. With the increase of relative moisture content of P. australis decomposing soil, content of every identified phenolic acid showed a downward trend, and the response curve of content of every identified phenolic acid to the relative moisture content of P. australis decomposing soil could be fitted well with a linear equation. Responses of coumarinic acid, gallic acid, and ferulic acid to soil moisture were the most obvious among eight kinds of identified phenolic acids. Therefore, coumanic acid, gallic acid, and ferulic acid can be used as the main regulatory targets, the allelopathic inhibitory effects of P. australis on Phalaris arundinacea can be weakened by regulating the moisture content of wetland soil so as to maintain the stability of Phragmites australis and Phalaris arundinacea community.