药用植物的连作障碍问题，已经严重制约了大中药产业链的可持续发展。研究证明，化感自毒作用是地黄连作障碍发生的源头。为了阐明地黄化感自毒物质的种类、结构和作用方式，本研究拟以HPLC-MS技术为依托，以"温85-5"地黄品种和地黄根区土壤为供试材料，通过构建目标成分的敲出技术体系，对化感自毒物质进行筛选，为揭示地黄连作障碍发生机制提供理论依据和技术支持。通过根区和空白土壤水提液指纹图谱的对比分析，确定目标成分，利用其分子离子峰和离子碎片裂解规律初步推断结构；在此基础上采用树脂、凝胶、反相色谱等技术，建立从土壤水提液中"敲出"目标成分的方法；采用盆栽法，对根区土壤水提液、目标成分及其阴性对照液进行连作障碍效应分析；通过生理指标测试、连作障碍率计算和数据分析，找到在地黄连作过程中起主导作用的化感自毒物质或物质群；鉴定化感物质结构并从信号转导、基因调控、植物反应等几个方面着手对其化感自毒效应进行验证。

Continuous monoculture problem in medicinal plant culture has became a core problem that hinders the sustanible development of industry chain of traditional Chinese Medicine. Previews researchs indicate that autotoxicity is origin of continuous monoculture disease of Rehmannia glutinosa. In order to indicate the structure and interaction of autotoxic substances, Rehmannia cultivars "wen-85-5" and its rhizosphere soil are the tested material in this research and a strategy based on target constituents knock-out proposed for allelochemical screening. Hence, contributes to provide theory basis and technical support to indicate mechanism of continuous monoculture problems in the production of Rehmannia glutinosa. HPLC-MS were employed to analyze the chemical constituents of effective fractions, and determine target compounds by comparing effective fraction chromatograph of water extraction from rhizosphere soil of Rehmannia glutinosa with that of the same fraction from blank soil. By Using the information of molecular ion peak, fragment ions and their fragmentation patterns, the structure of target compounds was inferred, which guides the isolation and purification of target constituent from water extraction by macroporous resin, LH - 20 gel, ODS or other chromatography. Pot experiments (exogenous adding obtained target constituents or its negative control into the pots for simulated continuous cropping condition) are carried out to test allelopathy effect of obtained target constituents on Rehmannia glutinosa. Thus, the growth and biochemical indexes can be determined and then index of harm can be calculated. Main allelochemical that lead to continuous monoculture problems of Rehmannia glutinosa can be screening with data analysis. Identify allelochemical structure by IR, NMR and MS data analysis. To test the validity of these allelochemical, Pot experiments (exogenous adding allelochemical into the pots) are carried out again and research signal transduction, regulation of gene expression and physiological effects of Rehmannia glutinosa caused by allelochemical.