肉苁蓉（Cistanche deserticola Ma）为列当科肉苁蓉属根寄生植物，具有补肝肾、益精血和润肠通便等功效，是我国传统补益类中药材。近年来肉苁蓉的市场需求剧增，野生肉苁蓉资源濒临灭绝，栽培肉苁蓉是解决肉苁蓉野生资源匮乏的重要途径。但由于肉苁蓉特殊的生长发育特性以及受生物和非生物因素影响，接种寄生率较低，栽培生产过程中需要的种子量大，造成种植成本高；并且栽培管理粗放，缺乏水肥管理经验，使肉苁蓉药材产量难以得到保证。解析肉苁蓉寄生机制是提升其药材产量的重要途径，但目前相关研究基础薄弱。本文初步研究了有机肥处理、土壤微生物以及梭梭根系提取物对肉苁蓉种子萌发与寄生的影响。主要研究结果如下：

1. 不同来源和肥量有机肥对肉苁蓉寄生和生长有一定影响。施用碳菌宝有机肥的肉苁蓉寄生率及鲜重最高，寄生率为30.0%，鲜重高达971.8 g；施用农家肥肉苁蓉寄生点数最多，为4.3个/株；碳菌宝和农家肥处理在茎数上无明显差异，但农家肥处理的小茎比例较高；腐殖酸型有机肥和微生物菌剂处理下肉苁蓉寄生率等指标均较低。施肥量高，肉苁蓉寄生率、寄生点数、茎数和鲜重均较高。结果显示，有机肥来源是影响鲜重的主要因子，肥量是影响肉苁蓉寄生率、寄生点数和茎数的主要因子。有机肥可有效促进肉苁蓉寄生，并且不同来源的有机肥的效果存在差异，施肥量加大可明显提高肉苁蓉寄生率和生长量。同时，施用有机肥能够有效改善土壤理化性质，施肥后有机质含量显著提高、pH显著下降，施用农家肥后土壤中速效钾、有机质和有效磷含量显著增加。土壤理化指标与肉苁蓉寄生率等指标显著相关，高寄生组土壤有效磷含量显著高于无寄生组。

2. 肉苁蓉接种土壤中微生物优势菌群占比高，多样性水平低，优势细菌门为放线菌门（Actinobacteria）、变形菌门（Proteobacteria）和绿弯菌门（Chloroflexi），优势细菌属为链霉菌属（Streptomyces）、类诺卡氏菌属（Nocardioides）和假诺卡菌属（Pseudonocardia）等；优势真菌门为子囊菌门（Ascomycota）、被孢菌门（Mortierellomycota）和担子菌门（Basidiomycota）等，优势真菌属为金孢菌属（Chrysosporium）、被孢霉属（Mortierella）和假裸囊菌属（Pseudogymnoascus）等。其中高寄生组土壤微生物种群多样性指数变异幅度最大，但肉苁蓉寄生率高低与土壤细菌、真菌种群相关性不显著。AM真菌门水平仅检测到毛霉门（Mucoromycota），包括球孢霉属（Glomus）、噬根菌（Rhizophagus）和根瘤菌属（Rhizoglomus）三个属，且不同寄生组土壤AM真菌丰度差异明显，有肉苁蓉寄生组噬根菌属丰度高，仅在高寄生组中存在根瘤菌属；零寄生组球孢霉属丰度较高。因此推测噬根菌属、根瘤菌属可能促进肉苁蓉寄生，球孢霉属不利于肉苁蓉寄生。

3. 藜科植物梭梭和甜菜根系浸提液对肉苁蓉种子萌发均无显著影响；添加赤霉素可有效促进肉苁蓉种子萌发，但萌发的种子均未形成吸器。而添加氟啶酮的两种寄主根浸提液均可诱导吸器形成，且梭梭根浸提液诱导的肉苁蓉吸器形成率较高，达16.2%。醇提液较水提液诱导吸器形成的作用更强。氟啶酮和赤霉素协同促进肉苁蓉种子萌发，萌发率可提高至52.3%，但吸器形成率无增加。不同培养液诱导肉苁蓉种子的吸器形态和位置有差异，寄主根浸提液诱导的吸器形成于芽管顶端，为多个乳头状凸起；仅低浓度氟啶酮处理产生类吸器状结构，但位置不固定，为单个圆形凸起或分叉。结果表明，肉苁蓉寄生关键结构—吸器的形成受寄主根浸提液中的某些物质的诱导，乙醇浸提和水浸提均能提取到这种物质，但醇提效果较好。

肉苁蓉种子萌发与寄生受土壤养分、微生物和寄主根系信号物质等多种生态因子的协同联合影响。本文初步明确了不同来源有机肥和施肥量对土壤理化性状的影响，发现有效磷含量与肉苁蓉寄生率显著相关；通过分析土壤微生物对肉苁蓉种子萌发与寄生的作用，发现寄生土壤中优势菌群占比高，菌群物种多样性低，生态平衡容易被破坏，AM真菌种类与肉苁蓉寄生率具有一定的相关性；同时发现肉苁蓉寄主根系浸提液中含有诱导吸器形成的关键物质。研究结果可为肉苁蓉科学施肥和土壤改良提供依据，为肉苁蓉寄生机制的研究提供参考。

Cistanche deserticola Ma is a root parasitic plant of Orobanchaceae, which has the functions of tonifying liver and kidney, enriching essence and blood, and moistening intestines and laxatives. It is a traditional Chinese herbal medicine. In recent years, the market demand of C. deserticola has increased dramatically, and the wild resources of C. deserticola are on the verge of extinction. Cultivation of C. deserticola is an important way to solve the shortage of wild resources of C. deserticola. However, due to the special growth and development characteristics of C. deserticola and the influence of biological and abiotic factors, the parasitic rate is low, and the seeds needed in the cultivation process are large, resulting in high planting costs. Moreover, crude cultivation management such as lack of experience in water and fertilizer management so it difficult to guarantee the yield of C. deserticola. The analysis of parasitic mechanism of C. deserticola is an important way to improve the yield of medicinal materials, but the current research foundation is weak. In this paper, the effects of organic fertilizer treatment, soil microorganisms and Haloxylon ammodendron root extracts on seed germination and parasitism of C. deserticola were studied. The main research results are as follows :

1. Different sources of organic fertilizer and different amounts of fertilizer had certain effects on parasitic and growth of C. deserticola. Fertilizer amount is the main factor of parasitic rate, number of parasitic seeds and stem number of C. deserticola, organic fertilizer source is the main factor of fresh weight. The parasitic rate and fresh weight of C. deserticola were the highest with 30 % parasitic rate and 971.78 g fresh weight after using tanjunbao. The number of parasitic seeds of C. deserticola was the most with 4.33 per plant. tanjunbao and farm manure had no difference in stem number, but farm manure had higher proportion of small stem. The parasitic rate of C. deserticola was low under humic acid organic fertilizer and microbial product in agriculture treatment. The parasitism rate, number of seeds parasitism, stem number and fresh weight of C. deserticola were higher with higher fertilization. The results showed that organic fertilizer could effectively promote the parasitism of C. deserticola, and the effect of organic fertilizer from different sources was different. The increase of fertilization amount could significantly improve the growth of parasitic rate of C. deserticola. The application of organic fertilizer can effectively improve the physical and chemical properties of soil. After fertilization, the content of organic matter increased significantly, and the pH decreased significantly. After application of farm manure, the contents of available potassium, organic matter and available phosphorus in soil increased significantly. Soil physical and chemical indexes were significantly correlated with parasitism rate of C. deserticola. Soil available phosphorus content in high parasitism group was significantly higher than that in nonparasitism group.

2. The dominant bacteria in the soil of C. deserticola were high in proportion and low in diversity. The dominant bacteria in phylum level were Actinobacteria, Proteobacteria and Chloroflexi etc., and the dominant bacteria in genus level were Streptomyces, Nocardioides and Pseudonocardia etc.. The dominant fungi in phylum level are Ascomycota, Mortierellomycota and Basidiomycota etc., and the dominant fungi in genus level are Chrysosporium, Mortierella and Pseudogymnoascus etc.. The diversity index of soil microorganism population in high parasitic group was the largest, but the parasitic rate of C. deserticola was not significantly correlated with soil bacteria and fungi population. Arbuscular mycorrhizal fungi was only detected in Mucoromycota, which was Glomus, Rhizophagus and Rhizoglomus, and the soil AM fungi abundance of different parasitic groups was significantly different, and the abundance of Rhizophagus in Cistanche parasitism group was high, and only Rhizoglomus existed in the high parasitic group; The abundance of Glomus in the zero parasitism group was high. Therefore, it is suggested that Rhizophagus and Rhizoglomus may promote the parasitism of Cistanche, and the Glomus is not conducive to Cistanche parasitism.

3. Root extracts of H. ammodendron and Beta vulgaris had no significant effect on seed germination of C. deserticola. The addition of gibberellin could effectively promote the germination of C. deserticola seeds, but the germinated seeds did not form haustorium.  However, the two extracts of host roots added with fluridone could induce the formation of haustorium, and haustorium formation rate of C. deserticola induced by H. ammodendron root extract was high, reaching 16.2%. The effect of ethanol extract is stronger than that of water extract. Fluridone and gibberellin synergistically promoted the germination of C. deserticola seeds, and the germination rate increased to 52.3%, but the formation rate of haustorium did not increase. The shape and position of the haustorium induced by different culture mediums were different. The haustorium induced by the host root extract formed at the top of the bud tube and were multiple papillary bulges. Only low-concentration fluridone treatment produces a haustorium-like structure, but the position is not fixed, which is a single round bulge or bifurcation. The results showed that the key structure of C. deserticola seed was induced by some substances in the host root extract, which could be extracted by ethanol extraction and water extraction, but the ethanol extraction effect was better.

Seed germination and parasitism of C. deserticola are affected by various ecological factors such as soil nutrients, microorganisms and signal substances of host roots. In this paper, the effects of different sources of organic fertilizer and fertilization on soil physical and chemical properties were preliminarily clarified, and it was found that the effective phosphorus content was significantly correlated with the parasitic rate of C. deserticola. By analyzing the effect of soil microorganisms on seed germination and parasitism of C. deserticola, it was found that the proportion of dominant bacteria in parasitic soil was high, the diversity of bacterial species was low, and the ecological balance was easy to be destroyed. The species of AM fungi had a certain correlation with the parasitic rate of C. deserticola. At the same time, it was found that the root extract of C. deserticola host contained key substances that induced the formation of haustorium. The results can provide basis for scientific fertilization and soil improvement of C. deserticola, and provide reference for the study of parasitic mechanism of C. deserticola.