连作三七根际土壤化感物质检测及其提取液对三种作物种子萌发的影响

Allelochemical detection from rhizosphere soil of continuouscropping Panax notoginseng and effects of the extracts on seed germination of three crops

【目的】探讨连作三七根际土壤中化感物质的种类及土壤浸提液对不同作物种子萌发的影响,为揭示连作三七根际土壤的化感作用机理提供理论依据。【方法】采用高效液相色谱分析(HPLC)测定未种植过三七的生土及种植1年、2年和3年三七的根际土壤中化感物质的种类及相对含量,并采用生物测定方法检测不同土壤浸提液对当地常见大田作物油菜、玉米和白菜种子萌发的影响。【结果】不同种植年限三七根际土壤中均检测到酚酸类化合物,随着种植年限的增加,除肉桂酸外,多数酚酸类化合物的含量(通过峰面积判断)较生土呈下降趋势,但无明显变化规律。同一种植年限下,较生土而言,随着土壤水提液浓度的增大,3种作物种子的萌发率整体上呈升高趋势;同一土壤水提液浓度处理下,种植3年三七的根际土壤水提取液对3种作物种子萌发的促进作用明显高于其他年限根际土壤水提液。不同溶剂土壤提取液处理下,随着土壤提取液浓度的提高,3种作物发芽率、发芽势及发芽指数逐渐表现出差异,多随着提取液浓度的增加,表现出促进作用。【结论】三七连作土壤中的大多数酚酸类化合物可能不是主要的化感物质,其土壤提取液对部分作物种子的萌发表现出浓度依赖性。

[Objective]Effects of allelochemicals in Panax notoginseng rhizosphere soil and soil extract on germina-tion of different seeds were studied in order to provide reference for revealing allelopathy mechanism of continuous cro-pping P. notoginseng rhizosphere soil. [Method]The species and concentration of allelochemicals from uncultivated soil, soil of one-year-cropping,soil of two years-cropping and soil of three years-cropping were examined through high perfor-mance liquid chromatogrophy（HPLC） method. Effects of soil extracts on seed germination of rape,corn and Chinese ca-bbage were analyzed by bioassay method. [Result]Phenolic acid compounds were detected in P. notoginseng rhizosphere soil with different cropping years. As cropping years increased, the contents of most phenolic acid compounds except cin-namic acid showed an decreasing trend compared with uncultivated soil（judged from peak area）, but there was no obvious regulation. Under the same cropping year, as concentration of soil extracts increased, the seed germination rate of the three crops rose as a whole. When the concentrations of soil extracts were the same, the effects of extracts from soil of three-year-cropping on seed germination were more obvious than others. When extracted by different solvents, as concen-tration of soil extracts increased, germination rate, germination potential and germination index of the three crops began to vary. Most of the indexes were enhanced as concentration of solvents increased. [Conclusion]Most phenolic acid com-pounds in P. notoginseng rhizosphere soil with different cropping years may not be the main allelochemicals. The soil ex-tracts show concentration dependence on seeds germination.