中文摘要：

太子参为石竹科多年生草本植物,以根部入药,药用价值高,市场需求大,但其栽培过程中存在严重的连作障碍问题,连作导致产量品质严重下降,病虫害猖獗,探索太子参连作障碍形成的机制及其消减措施意义重大.本研究以广泛栽培的“柘参2号”为试验材料,采用土壤农化分析、高效液相色谱（HPLC）分析、荧光定量PCR（qPCR）等技术对不同连作年限或不同消减措施下太子参根际土壤的主要养分、酚酸含量动态及特异菌群变化进行分析.结果显示：太子参连作导致产量显著下降,与正茬相比产量下降达43.5%,而水旱轮作和微生物菌肥处理可不同程度缓解其障碍效应.太子参连作土壤主要养分（如速效氮、速效磷、速效钾、全钾）未降反升,但导致土壤酸化.HPLC分析表明,太子参连作下或者随生长时期的推进,土壤酚酸类物质并未表现出明显的积累效应,膨大中期和收获期重茬土壤中大部分酚酸含量甚至低于正茬土壤.进一步荧光定量PCR分析发现,太子参连作导致前期分离筛选到的几类病原菌（如尖孢镰刀菌、踝节霉菌、Kosakonia sacchari）的绝对含量显著上升,而水旱轮作和微生物菌肥处理可有效降低3类病原菌的含量,改善微生态结构.综上认为,太子参连作障碍的发生并非由土壤养分匮乏或者酚酸持续积累直接造成,可能主要与连作下土传病原微生物的大量繁殖爆发有关,本研究结果为深入揭示太子参连作障碍的形成机制及消减修复机制提供了理论依据.

英文摘要：

Pseudostellaria heterophylla is a perennial herbaceous plant in the family Caryophyllace- ae. The tuberous roots of P. heterophylla are highly valued in traditional Chinese medicine and have a high market demand. However, extended monocuhure of P. heterophylla results in a significant decline in the biomass and quality, and escalates disease and pest problems. Therefore, it is impor- tant to understand the underlying mechanism and biocontrol methods for consecutive monocuhure problems. With ＂Zheshen 2＂ as an experimental material, the changes in the contents of main nu- trients in soil, phenolic acids and specific microbes under monoculture and different amendments were analyzed by using high performance liquid chromatography （HPLC） and qPCR. The results showed that consecutive monoculture of P. heterophylla led to a decrease in yield by 43.5% while the microbial fertilizer treatment and the paddy-upland rotation could relieve the consecutive mono- culture problems. Available nitrogen, available phosphorus, available potassium and total potassium were significantly higher in the consecutively monocultured soils than in the newly planted soils. But consecutive monocuhure resulted in soil acidification. HPLC analysis showed that conse-cutive mon- oculture of this plant did not lead to a consistent accumulation of soil phenolic acids. At middle stage of root expansion and at harvest stage, most of phenolic acids were even higher in the newly planted soils than in the consecutively monocuhured soils. Furthermore, qPCR analysis showed that the amounts of three specific pathogens identified previously （ i.e. Fusarium oxysporum, Talaromyces helicus, Kosakonia sacchari） were significantly higher in the consecutively monocultured soils than in the newly planted soils. However, the microbial fertilizer treatment and the paddy-upland rotation resulted in a significant decline in the population of these specific pathogens and improved the soil environment. In conclusion, the consecutive monoculture problems of P.