【作者】 段佳丽；

【导师】 薛泉宏；

【作者基本信息】 西北农林科技大学 ， 资源环境生物学， 2013， 博士

【摘要】 作为国内外需求量日益增加的热门药用植物，丹参连作根系病害已成为其人工栽培扩大化的主要限制因素，寻找合适有效的病害防治途径是目前解决丹参根系病害问题的首要任务。本研究从根际微生态角度出发，通过对丹参病株与健株根系、根区及根表土壤微生物区系，以及根区土壤与叶片养分的系统比较研究，确定了丹参根部病害的主要致病菌及优势微生物，揭示了丹参3种根部病害发生的土壤微生态机制；通过丹参根腐病病原菌分离鉴定及拮抗放线菌筛选鉴定，获得了丹参根腐病的致病菌及8株有较强拮抗作用的广谱生防放线菌；通过2年田间试验，证实了生防放线菌对丹参的防病促生效果，初步探明了放线菌剂作用的微生态机理。该结果为丹参连作土传根部病害微生态机制揭示及微生物修复技术研究提供了新的理论依据、试验证据及生防菌株。论文主要研究结果如下：（1）丹参根系内生细菌的分离鉴定及其生物活性从收获期丹参健株根系韧皮部、木质部中分离得到6株可培养内生细菌，分别归属于假单胞菌属（Pseudomonas）、根瘤菌属（Rhizobium）、芽孢杆菌属（Bacillus）和新鞘脂菌属（Novosphingobium）。研究发现放射型根瘤菌（R. radiobacter）和阿氏芽孢杆菌（B. aryabhattai）这2株细菌的细胞悬液(约10⁹cell·mL^-1)以及十字花科假单胞菌（Ps.brassicacearum subsp. neoaurantiaca）、放射型根瘤菌（R. radiobacter）、假单胞菌属帚形菌（Ps. thivervalensis）和阿氏芽孢杆菌（B. aryabhattai）这4株细菌的无细胞发酵滤液对甜瓜种子的胚轴和胚根有明显的促生作用。但是这6株内生细菌的无细胞发酵滤液对丹参根腐病病原真菌均无明显的抑菌活性。（2）丹参3种根部病害发生的微生态机制对丹参红叶病、枯萎病和根腐病病株与健株根区土壤与叶片养分，以及根区、根表土壤中的微生物区系分别进行比较研究，探索根部病害发生的微生态机制。丹参红叶病：①红叶病植株叶片中N、P、K元素含量均显著低于健株，而根区土中速效P元素与健株根区土无显著差异，速效N、K元素含量均显著高于健株根区土，表明丹参红叶病害发生与P元素缺乏有关，但植株缺磷不是由于土壤供磷不足所致。②与健株相比，丹参红叶病植株根区、根表土壤中细菌数量分别减少41.3%、78.8%，真菌数量分别增加156.6%、14.3%，放线菌数量分别增加189.5%、127.5%。③在丹参红叶病株根区、根表土壤中，6种优势真菌、4种优势放线菌及2种优势细菌可能为有害微生物。优势真菌为腐皮镰刀菌（Fusarium solani）、露湿漆斑菌（Myrothecium roridum）、三线镰刀菌（F. tricinctum）、焦曲霉（Aspergillus calidoustus）、尖孢镰刀菌（F. oxysporum）及座囊菌（Dothideomycetes sp.）；优势放线菌为砖红链霉菌（Streptomyces lateritius）、威威达湖伦茨氏菌（Lentzea waywayandensis）、马铃薯疮痂病原链霉菌（S. stelliscabiei）及山丘链霉菌（S. collinus）；优势细菌为阿氏芽孢杆菌（B. aryabhattai）及水生细菌（Piscinibacter aquaticus）。这些优势微生物可能通过影响根系生长及根系对土壤养分吸收引起丹参出现缺磷现象。丹参枯萎病：①在丹参枯萎和枯死病株叶片组织中，N、P、K含量均显著低于健株；而在根区土壤中，有机质和N、P、K含量均高于健株。说明枯萎病发生与土壤养分供应无关。②丹参枯死病株根区土壤细菌、真菌和放线菌数量分别较健株增加168.0%、852.8%和247.4%（P＜0.05），根表土壤中细菌、真菌和放线菌数量分别较健株增加72.6%、2020.0%和424.2%（P＜0.05）。③在丹参枯萎和枯死病株根区、根表土壤中，2种优势真菌腐皮镰刀菌（F. solani）和尖孢镰刀菌（F. oxysporum）均为植物根系病害病原菌。在枯死病株的根区及根表土壤中：这两种真菌总数分别占优势真菌总数的61.8%及100%，其中腐皮镰刀菌分别占57.0%及99.6%，其数量分别为健株的7.4倍及75.9倍，即腐皮镰刀菌为丹参枯萎病的主要致病菌。丹参枯萎病的发生与丹参根区、根表土壤微生物区系异常密切相关，其中腐皮镰刀菌的大量增加是病害发生的主要原因。丹参根腐病：①在发病末期病株叶片中，N、P、K元素含量均高于健株。并且病株根区土壤的有机质和速效养分含量均高于健株根区土壤，其中有机质、速效P和速效K在发病末期植株根区土壤中含量最高，分别是健株的2.9、2.3和1.6倍，同时pH值最低，较健株根区土壤低12.3%。说明丹参根腐病的发生与土壤养分供应无明显关系，且病株根系因病原菌侵染导致吸收功能下降，引起病株根区土壤中速效磷钾残留量大幅度增加。②在丹参根区土壤中，发病初期、中期及末期病株细菌数量分别较对照减少36.5%、54.1%及80.2%；真菌数量分别较健株增加160.8%、191.0%及310.6%；发病中期和末期病株放线菌数量分别减少52.2%和51.9%。在根表土壤中，发病初期、中期及末期病株细菌数量分别较对照减少35.0%、增加147.7%及498.0%；发病初期、中期及末期病株真菌数量分别较对照增加364.0%、365.8%及1312.9%；发病初期和末期病株放线菌数量分别较对照增加158.4%和989.1%。在丹参根系中，发病初期、中期及末期病株的细菌数量分别是健株的1.5、24.3及13.1倍；发病末期丹参病株根系真菌数量约是中期病株的4.3倍，且放线菌数量较健株增加225.6%。③在丹参病健株根区、根表土壤以及根系中分离得到6株优势真菌，有4种为疑似有害微生物，分别为尖孢镰刀菌（F. oxysporum）、腐皮镰刀菌（F. solani）、镰刀菌（Fusarium sp.）及布雷正青霉（Penicillium. brefeldianum），其中尖孢镰刀菌（F. oxysporum）和腐皮镰刀菌（F. solani）均是已知的植物根系病害致病菌。丹参根腐病的发生与土壤微生物区系异常密切相关，根区、根表土壤真菌数量大幅度增加是丹参根腐病发病的重要原因之一。综上所述，丹参红叶病、枯萎病和根腐病的发生与丹参根区、根表土壤中微生物区系异常密切相关，与土壤养分供应无显著关系，且根系发病后还会导致丹参根系吸收功能下降，根区土壤中速效磷钾残留量大幅度增加。（3）丹参根腐病病原真菌分离鉴定采用组织块分离法从丹参根腐病植株根系中共获得19株真菌分离物，通过丹参根系离体侵染试验得到4株病原真菌，通过形态特征及rDNA-ITS序列分析将其鉴定为腐皮镰刀菌（F. solani）和尖孢镰刀菌（F. oxysporum）各2株。（4）丹参根腐病拮抗放线菌筛选鉴定利用琼脂块拮抗圈测定和发酵液抑菌率测定法从300株供试放线菌中筛选出22株对腐皮镰刀菌（F. solani）和尖孢镰刀菌（F. oxysporum）有显著拮抗性的放线菌，其中有8株具有广谱抑菌活性（D62，F54，D3，D38，Act8，L8，Act12，Act1），分别为锈赤蜡黄链霉菌（S. rubiginosohelvolus, D62）、林可链霉菌（S. lincolnensis, D3）、橄榄色链霉菌（S. olivaceus, D38）、密旋链霉菌（S. pactum, L8, Act12）、加州链霉菌（S.californicus, Act1）以及（Streptomyces sp. F54, Act8）。其中放线菌D62、F54、D3和Act8对腐皮镰刀菌和尖孢镰刀菌抑制作用明显，抑菌率为31.0%～55.6%。菌株L8、D62和Act12对4株病原真菌的单位菌体抑菌率为18.3%～91.0%；菌株D62和F54对尖孢镰刀菌1的拮抗环宽度分别为7.0和6.8mm，其发酵滤液对其抑菌率分别达53.5%和51.4%。（5）Act12放线菌菌剂对丹参的促生作用及根域微生态的调整效应放线菌剂Act12+草木灰蘸根接种具有如下作用：①对丹参生长有明显的促进作用。在小区试验中，与对照相比，放线菌剂稀释10倍、100倍处理丹参茎叶鲜质量分别增加29.7%、35.5%，根鲜质量分别增加44.0%、39.6%，根干质量分别增加26.3%、33.3%。在大田试验中，放线菌剂蘸根处理丹参增产2022.0kg·hm-2。②能显著提高丹参产量及药材中丹参酮IIA、丹酚酸B和丹参素含量及单株产量，改善药材品质。在小区试验中，放线菌剂稀释100倍处理丹参根内丹参酮ⅡA、丹酚酸B及丹参素含量分别较对照增加175.0%、102.6%及110.0%，三者产量分别较对照增加348.7%、230.6%及242.6%。在大田试验中，放线菌剂蘸根处理丹参根内丹酚酸B、丹参素含量分别较对照增加19.4%、20.8%，二者产量分别较对照增加27.1%、28.5%。③能明显调整丹参植株根域土壤微生态平衡，减少有害微生物数量，增加有益微生物数量，改善微生物区系。在丹参根区土壤中，放线菌处理细菌、真菌数量分别较对照减少58.8%、34.8%，放线菌数量较对照增加85.3%。③在放线菌处理丹参根区、根表土壤中，有7种优势微生物可能对丹参生长有促进及抗病作用：2株优势细菌假中间苍白杆菌（Ochrobactrum. pseudogrignonense）和鞘脂菌（Sphingobium aromaticiconvertens）；5株优势放线菌为黄暗色链霉菌（S.xanthophaeus）、微管螺旋链霉菌（S. capillispiralis）、马特链霉菌（S. matensis）、教酒链霉菌（S. chartreusis）和林可链霉菌（S. lincolnensis）。有4株优势真菌可能对丹参根系有害，分别为黄曲霉（As. flavus）、黑曲霉（As. niger）、露湿漆斑菌（M. roridum）和红球丛赤壳菌（Nectria haematococca）。关于这几种真菌对其他作物的有害作用已有报道。④放线菌剂接种对丹参根结线虫侵染有强烈抑制作用，可使大田根结线虫侵染率降低50%，但其机制尚不清楚，可能与放线菌剂减弱了病原菌真菌对丹参根系的侵染，导致线虫侵染下降所致。（6）Act12放线菌剂与腐植酸钾配施对丹参的促生作用及根域微生态的调整效应Act12放线菌菌剂与腐植酸钾混合施用具有如下作用：①能增强菌剂对丹参的促生效果。菌剂与腐植酸钾配施处理丹参成活率较对照提高8.7%，收获时的死亡率较对照减少39.0%；茎叶鲜质量、根鲜质量、单株根鲜质量、根干质量以及单株根干质量分别较对照增加6.1%、28.6%、11.1%、36.3%以及9.0%。②可以调整丹参植株根域土壤微生态平衡，降低有害微生物数量，增加有益微生物数量，改善微生物区系。在丹参根表土壤中，菌剂与腐植酸钾配施处理B/A值较对照降低78.4%，A/F值较对照增加95.0%。在丹参根系内，菌剂与腐植酸钾配施处理细菌数量较对照增加195.0%，未检测到真菌和放线菌存在。③在放线菌处理丹参根区、根表土壤中，有6种优势菌可能对丹参生长及抗病有益：3株优势细菌分别为硝基愈疮木胶节杆菌（Arthrobacter nitroguajacolicus）、放射型根瘤菌（R. radiobacter）和弗雷德里克斯堡假单胞菌（Ps. frederiksbergensis）；3株优势放线菌分别为淀粉酶产色链霉菌（S. diastatochromogenes）、砖红链霉菌（S.lateritius）和卡伍尔链霉菌（S. cavourensis）。有2株优势菌疑为有害微生物：优势细菌为耐寒短杆菌（B. frigoritolerans），1株优势放线菌为肿痂链霉菌（S. turgidiscabies）。这2种菌对其他作物的有害作用已有报道。④对丹参根结线虫侵染有强烈抑制作用，可使田间根结线虫侵染率降低49.6%。更多还原

【Abstract】 As a well-known traditional Chinese medicinal herb, the international and domesticdemand of Salvia miltiorrhiza Bge. is increasing fast. Consequently, replant disease is themajor limiting factors of the development of S. miltiorrhiza artificial cultivation. Findingeffective disease control approaches is the first priority to solve this problem. In order toelucidate reasons for the occurrence of S. miltiorrhiza root diseases, changes of rhizospheresoil and leaves chemical properties and microbial community composition between healthyand diseased S. miltiorrhiza plants root, rhizosphere and rhizoplane soil were determined byroutine soil agro-chemistry analysis and culture-depended method, respectively. Meanwhile,based on the research of isolation and identification of pathogenic fungi from root rot plant,screening and identification of antagonistic actinomycetes,8strains broad spectrumantagonistic actinomycetes were obtained.2-years field experiment was conducted to studythe biocontrol and growth promotion effect of actinomycetes and its microecologicalmechanism. The related results studies provided theoretical basis, experimental evidence andbiocontrol actinomycetes for indication of microecological mechanism and research ofmicrobial remediation of replant soil-borne root disease in S. miltiorrhiza. Related results andconclusions are listed as follows:（1） Isolation and identification of endophytic bacteria from root tissues of S. miltiorrhizaand determination of their bioactivitiesThis study examined the occurrence, distribution, growth-promoting and antifungalactivities of endophytes in the root of S. miltiorrhiza. Six endophytic bacterial strains, whichbelong to genera of Pseudomonas, Rhizobium, Bacillus and Novosphingobium, were isolatedfrom the root of healthy S. miltiorrhiza. Cell suspension (approx.10⁹cell·mL^-1) of twoisolates namely R. radiobacter, B. aryabhattai and cell-free fermentation filtrate of fourisolates namely Ps. brassicacearum subsp. neoaurantiaca, R. radiobacter, Ps. thivervalensis,B. aryabhattai substantially promoted the growth of hypocotyl and radicle of muskmelonseeds. The cell-free fermentation filtrate of six isolates had no inhibiting effect on testedpathogenic fungi namely Fusarium solani, F. oxysporum f. sp. vasinfectum and F. oxysporum. This work indicates that endophytic bacteria occur in the root of S. miltiorrhiza, and thatassociated bacterial isolates have growth-promoting effect on muskmelon seeds and areexpected to be a potential source for bioactive metabolites.（2） Microecological mechnism of root diseases occurrence of S. miltiorrhizaThe microecological mechanism of the red-leaf diseased, Fusarium wilt infected and rootrot diseased S. miltiorrhiza were studied by determination and comparison of soil nutritioncontents and microflora in the root zones of healthy and infected plants. Normal method wasused to measure the content of soil and leaf nutrition, the amount of bacteria, actionmycetes,fungi and the ratio of B/F, A/F, B/A in the rhizosphere, rhizoplane and bulk soil by dilution,and semar technique was used to do the molecular biology identification of the dominantmicrobes and to study the microecological mechanism of diseased S. miltiorrhiza in rootingzone soil.Red-leaf diseased S. miltiorrhiza:①The available N, P and K contents in rhizospheresoil of diseased S. miltiorrhiza leaves were all significantly lower than in healthy S.miltiorrhiza leaves, while there was no significant difference of available P content inrhizosphere soil between the diseased and the healthy S. miltiorrhiza. These indicated thedeficiency of P in S. miltiorrhiza leaves was the primary cause of the red-leaf disease.②Thenumber of bacteria in the rhizosphere soil of diseased S. miltiorrhiza decreased sharply, whilethe numbers of fungi and actinomycetes increased enormously; compared to the healthy S.miltiorrhiza, the number of bacteria decreased by41.3%, whilst the numbers of fungi andactinomycetes increased by156.6%,189.5%, respectively. The dynamic of the numbers ofbacteria, fungi and actinomycetes in the rhizoplane soil of diseased S. miltiorrhiza was as thesame as the rhizosphere soil.③The numbers of predominant bacteria （B. aryabhattai,Piscinibacter aquaticus）, the predominant fungi （F. solani, Myrothecium roridum, F.tricinctum, Aspergillus calidoustus, F. oxysporum, Dothideomycetes sp.） and the predominantactinomycetes （Streptomyces lateritius, Lentzea waywayandensis, S. stelliscabiei, S. collinus）in the root zone soil were higher in the diseased S. miltiorrhiza than in the healthy plant,which could resulted in the red-leaf disease of S. miltiorrhiza.Fusarium wilt infected S. miltiorrhiza:①Compared to those in the healthy plant leaves,N, P, K contents significantly decreased by8.4%,35.6%,23.5%and23.4%,57.6%,57.7%inwithered and dead plant leaves （P＜0.05）. Compared to those in the healthy plant rhizosphere,soil organic matter and available N, P, K contents increased in infected plant rhizosphere. Itshowed that the occurrence of Fusarium wilt was independent of soil nutrient deficiency.②In dead plant rhizosphere, the numbers of soil bacteria, fungi and actinomycetes respectivelyincreased by168.0%,852.8%and247.4%compared to those in the healthy plant rhizosphere （P＜0.05）. In dead plant rhizoplane, the numbers of soil bacteria, fungi and actinomycetesrespectively increased by72.6%,2020.0%and424.2%compared to those in the healthy plantrhizosphere （P＜0.05）.③In infected plant rhizosphere and rhizoplane soils, predominantmicrobial species that might be harmful were mainly2fungi isolates （F. solani and F.oxysporum）. These predominant soil microbes likely caused Fusarium wilt by negativelyaffecting the growth of roots and their absorption of nutrient from soil.Root rot diseased S. miltiorrhiza:①The content of available N, P and K interminal-stage infected plant leaves were higher than in healthy plant leaves. Compared tothose in the healthy plant rhizosphere, soil organic matter and available nutrient contents allincreased in infected plant rhizosphere soil. Soil organic matter, available P and K contentswere highest in terminal-stage infected plant rhizosphere soil and were respectively2.9,2.3and1.6times of that in the healthy plant rhizosphere soil, and pH decreased by12.3%compared with the control. It showed that the occurrence of root rot was independent of soilnutrient deficiency.②In rhizosphere soil, compared to those in the healthy plant, thenumbers of soil bacteria in initial-stage, middle-stage and terminal-stage infected plantincreased by36.5%,54.1%and80.2%, respectively; the numbers of fungi in initial-stage,middle-stage and terminal-stage infected plant increased by160.8%,191.0%and310.6%,respectively; the numbers of actinomycetes in middle-stage and terminal-stage infected plantdecreased by52.2%and51.9%, respectively. In rhizoplane soil, compared to those in thehealthy plant, the numbers of soil bacteria decreased by35.0%in initial-stage infected plant,while increased by147.7%and498.0%in middle-stage and terminal-stage infected plant,respectively; the numbers of fungi in initial-stage, middle-stage and terminal-stage infectedplant increased by364.0%,365.8%and1312.9%, respectively; the numbers of actinomycetesin initial-stage and terminal-stage infected plant increased by158.4%and989.1%,respectively. In S. miltiorrhiza roots, the numbers of bacteria in initial-stage, middle-stage andterminal-stage infected plant were1.5,24.3and13.1times of the control, respectively. Fungiwere only detected in middle-stage and terminal-stage infected plant, and the number of fungiin terminal-stage infected plant was4.3times of that in middle-stage infected plant; while thenumber of actinomycetes in terminal-stage infected plant was225.6%higher than the control;B/A in middle-stage infected plant was350.0%higher than the control.③6predominantfungi were isolated from S. miltiorrhiza rhizosphere, rhizoplane soils and root, of which4isolates were suspected harmful organisms. They were identified as F. oxysporum, F. solani,Fusarium sp. and Penicillium brefeldianum. The main pathogenic fungi were F. oxysporumand F. solani. These predominant soil microbes likely caused root rot disease by negativelyaffecting the growth of roots and their absorption of nutrient from soil. In conclusion, the occurence of root diseases in S. miltiorrhiza are mainly caused byabnormal soil microflora in plant rhizosphere and rhizoplane soil. In addition, root diseasescould lead a decline of S. miltiorrhiza root absorption function, which made a substantialincrease in residual available P, K in rhizosphere soil.（3） Isolation and identification of pathogenic fungi from root rot diseased S. miltiorrhizaFrom the infected S. miltiorrhiz plant roots,19fungi isolates were collected by tissueseparation method.4pathogenic fungi were screened by in vitro infection test of S. miltiorrhizroots and further attributed to2genus and2species, which were Fusarium solani1, F. solani2, F. oxysporum f. sp. vasinfectum1and F. oxysporum2, according to morphologicalcharacters and rDNA-ITS sequence analysis.（4） Screening and identification of antagonistic actinomycetes against pathogenic fungifrom root rot diseased S. miltiorrhiza22strains of antagonistic actinomycetes, which had obvious inhibitory effects on F.solani and F. oxysporum were screened from the300tested actinomycetes with agar blockmethod and growth rate method, included8strains of broad spectrum actinomycetes （D62,F54, D3, D38, Act8, L8, Act12, Act1） against the4pathogenic fungi. The inhibitory effectsof actinomycetes D62, F54, D3and Act8were obvious on F. solani and F. oxysporum, whichinhibitory rates were31.0%-55.6%. And the unit mycelium inhibitory rates of L8, D62andAct12on the4pathogenic fungi were114.5-691.7%·g-1; The inhibitory rings of D62and F54were7.0mm and6.8mm on F.oxysporum1, and the inhibitory rates reached53.5%and51.4%. The8broad spectrum actinomycetes isolates were identified as S. rubiginosohelvolus（D62）, S. lincolnensis （D3）, S. olivaceus （D38）, S. pactum （L8, Act12）, S. californicus （Act1）and Streptomyces sp.（F54, Act8）.（5） The growth promoting and adjusted effect in rooting zone of biomicrobialactinomycetes Act12on S. miltiorrhiza①Root dipping of actinomycetes Act12preparation showd favorable growth and yieldpromotion effect on S. miltiorrhiza. In the plot experiment, inoculating with actinomycetes of10and100times dilution, the stem-leaf natural weight increased by29.7%and35.5%respectively compared with the control treatment; the root natural weight increased by44.0%and39.6%respectively, and root dry weight increased by26.3%and33.3%respectively. Inthe field experiment, inoculating with actinomycetes preparation, the yield of root naturalweight increased2022.0kg·hm-2.②Root dipping of actinomycetes Act12preparation canimprove medicine quality of S. miltiorrhiza root. In the plot experiment, under the treatmentof actinomyces diluted100times by wood ash, the contents of TanshinoneⅡA, Salvianolicacid B and Danshensu in S. miltiorrhiza all achieved maximum value which increased by 175.0%,102.6%and110.0%respectively compared with that of control. Similarly, thecontents of this three active constituents per plant increased by348.7%、230.6%and242.6%compared with that of control. In the field experiment, the contents of Salvianolic acid B andDanshensu in S. miltiorrhiza were19.4%and20.8%higher than that in the control treatment,also, the contents of this two active constituents per plant improved by27.1%and28.5%compared with the control treatment.③Inoculating with actinomycetes Act12can adjust soilmicroecological balance, modify microflora and microbial community composition byreducing amount of harmful organisms and increasing amount of beneficial organisms. Inrhizosphere soil, compared to those of control, inoculating with Act12of10times dilution,the numbers of bacteria and fungi decreased by58.8%and34.8%respectively, and thenumber of actinomycetes increased by85.3%.③In rhizosphere and rhizoplane soilinoculating with Act12treatment,7predominant microorganisms might be beneficial, whichincluded2bacteria isolates namely Ochrobactrum pseudogrignonense and Sphingobiumaromaticiconvertens,5actinomycetes isolates namely S. xanthophaeus, S. capillispiralis, S.matensis, S. chartreusis and S. lincolnensis;4predominant fungi are suspected harmfulorganisms, which are Aspergillus flavus, As. niger, M. roridum and Nectria haematococca.④Inoculating with actinomycetes may control the disease of root-knot nematode. The diseaseincidence of root-knot nematode in S. miltiorrhiza decreased by50%by using actinomycetesAct12preparation.（6） The growth promoting and adjusted effect in rooting zone of biomicrobialactinomycetes Act12combined with potassium humate on S. miltiorrhiza in fieldCombined application of Act12preparation with potassium humate enhanced the growthpromotion effect on S. miltiorrhiza.①Under Act12combined with potassium humatetreatment, survival rate increased by8.7%compared with the control treatment, and mortalityrate decreased by39.0%; Stem-leaf natural weight, root natural weight, root natural weightper plant, root dry weight and root dry weight per plant were6.1%、28.6%、11.1%、36.3%and9.0%higher than the control, respectively.②C ombined application of Act12preparation withpotassium humate can adjust soil microecological balance, modify microflora and microbialcommunity composition. In rhizoplane soil, compared with the control treatment, A/Fincreased by95.0%under Act12combined with potassium humate treatment. In S.miltiorrhiza roots, under Act12combined with potassium humate treatment, the number ofbacteria was195.0%higher than the control. While fungi and actinomyctes were not detected.③In rhizosphere and rhizoplane soil with Act12and potassium humate,6predominantmicroorganisms might be beneficial, which included3bacteria isolates namely Arthrobacternitroguajacolicus, R. radiobacter and Ps. frederiksbergensis,3actinomycetes isolates namely S. diastatochromogenes, S. lateritius and S. cavourensis;2predominant microorganisms weresuspected harmful isolates, included1bacteria isolate Brevibacterium frigoritolerans and1actinomycetes isolate S. turgidiscabies.③Combined application of Act12preparation withpotassium humate may control the disease of root-knot nematode. The disease incidence ofroot-knot nematode in S. miltiorrhiza decreased by49.6%by using Act12preparationcombined with potassium humate.更多还原