Isolation and Identification of Houttuynia cordata Endophytic Bacteria and Study of Antibiotic Activity

[Objectives]To further explore the resources of biocontrol strains and provide new options for the control of pathogenic bacteria.[Methods]Houttuynia cordata endophytic bacteria were isolated and identified,and the antibiotic activity was explored.[Results]There are 8 strains(H1-H8)of endophytic bacteria isolated from the healthy plants of H.cordata,which had an antagonistic effect on the pathogenic bacteria.According to the gene sequence,the 8 strains were identified as Stenotrophomonas,Pseudomonas,and Bacillus,which strongly inhibited Colletotrichum(HC1),Fusarium(HC2),and Rhizoctonia(HC5)of H.cordata.On the PDA culture dish,the inhibition diameter of the 8 strains on Colletotrichum,Fusarium,and Rhizoctonia was 6,8,and 5 mm,respectively.[Conclusions]Pathogenic bacteria and endophytic bacteria inoculated with H.cordata seedlings showed that endophytic bacteria have certain antagonistic activity,and have the potential for development and application.

铅、锌及其交互作用对鱼腥草(Houttuynia cordata)叶绿素含量及抗氧化酶系统的影响

采用营养液培养方法研究铅、锌及其交互作用对鱼腥草叶绿素含量及抗氧化酶系统的影响。实验结果显示,随着Pb浓度的增加,鱼腥草叶绿素含量逐渐降低但无显著变化。Zn在一定浓度下能提高鱼腥草叶绿素含量,而在高浓度Zn胁迫下,叶绿素含量急剧下降。鱼腥草叶片中SOD、POD和CAT3种酶活性都是随着Pb浓度的增加先上升后下降。随着Zn浓度的增加,SOD和CAT也是先上升后下降,POD则是逐渐上升。Pb-Zn交互作用增加了鱼腥草叶绿素含量,对SOD和POD活性具有抑制作用,对CAT活性影响不明显。同时研究结果还表明,单一Pb、Zn对鱼腥草叶绿素含量和抗氧化酶系统的影响大于Pb、Zn二者的共同作用,其中高浓度Zn对鱼腥草的伤害作用最大,而当溶液Pb处理浓度达到400mg/L时,鱼腥草仍能正常生长,说明鱼腥草具有较强的耐Pb能力。

峨眉山不同山峪和海拔高度鱼腥草(Houttuynia cordata Thunb.)居群挥发油成分的变化

以分布于峨眉山不同山峪不同海拔（500-1800m）的17个鱼腥草（Houttuynia cordata Thunb.）居群及生长地土样作为试验材料，按土壤农化分析常规方法对土壤pH值及土壤营养元素进行测定，用水蒸馏法提取植株地上部分的挥发油，并用GCMS对挥发油化学成分进行分离和鉴定，峰面积归一法测定各成分含量。结果显示：峨眉山鱼腥草生长地土壤肥力水平较高，对鱼腥草的生长极为有利。从所有居群中共鉴定出35种化合物，各居群挥发油成分组成及含量存在较大的差异。月桂烯作为四个山峪唯一共有的主要成分在各居群中均能检测到，且在各居群中的平均含量最高。乙酸龙脑酯和trans-β-罗勒烯的含量与海拔高度间分别存在显著和极显著正相关。方差分析及多重比较的结果表明，不同山峪以及海拔高度对各居群挥发油成分和含量有显著影响。通过偏相关分析发现土壤微量元素对鱼腥草挥发油共有成分合成与积累的作用大于大量元素，微量元素中以有效钼的影响最为显著，大量元素中以速效钾的影响最为显著。采用逐步多元回归分析筛选出了对挥发油共有成分含量影响显著的土壤营养元素。

Evaluation of antiviral activities of Houttuynia cordata Thunb.extract,quercetin,quercetrin and cinanserin on murine coronavirus and dengue virus infection

Objective:To evaluate the in vitro activities of the ethyl acetate(EA) fraction of Houttuynia cordata(H.cordata) Thunb.(Saururaceae) and three of its constituent flavonoids(quercetin.quercitrin and rutin) against murine coronavirus and dengue virus(DENV).Methods:The antiviral activities of various concentrations of the EA fraction of H.cordata and flavonoids were assessed using virus neutralization tests against mouse hepatitis virus(MHV) and DENV type 2(DENV-2).Cinanserin hydrochloride was also tested against MHV.The EA fraction of H.cordata was tested for acute oral toxicity in C57BL/6 mice.Results:The EA fraction of H.cordata inhibited viral infectivity up to 6 d.Cinanserin hydrochloride was able to inhibit MHV for only 2 d.The 50%inhibitory concentrations(IC_(50)) of the EA fraction of H.cordata added before the viral adsorption stage were 0.98 μg/mL for MHV and 7.50 μg/mL for DENV-2with absence of cytotoxicity.The mice fed with the EA fraction up to 2 000 mg/kg did not induce any signs of acute toxicity,with normal histological features of major organs.Certain flavonoids exhibited comparatively weaker antiviral activity,notably quercetin which could inhibit both MHV and DENV-2.This was followed by quercitrin which could inhibit DENV-2but not MHV,whereas rutin did not exert any inhibitory effect on either virus.When quercetin was combined with quercitrin,enhancement of anti-DENV-2 activity and reduced cytotoxicity were observed.However,the synergistic efficacy of the flavonoid combination was still less than that of the EA fraction.Conclusions:The compounds in H.cordata contribute to the superior antiviral efficacy of the EA fraction which lacked cytotoxicity in vitro and acute toxicity in vim.H.cordata has much potential for the development of antiviral agents against coronavirus and dengue infections.

Inhibitory effect of Houttuynia cordata Thunb on LPS-induced retinal microglial activation

AIM: To identify the effect of Houttuynia cordata Thunb(HCT) on lipopolysaccharide(LPS)-induced microglial activation and investigate its possible molecular mechanisms. METHODS: The primary retinal microglial cells were cultured from the retinas of newborn Sprague-Dawley rats and exposed to LPS, and/or HCT with different concentrations. The survival ability of retinal microglia cells was tested by standard MTT method. BrdU cell proliferation assay was used to evaluate the proliferation of retinal microglia. Inflammatory factors in the culture supernatants, including TNF-α, iNOS and IL-1β, were measured using ELISA. Microglia cells’ migration was determined with Transwell migration assay. The total p38-MAPK and phosphorylation of p38-MAPK(p-p38-MAPK) were detected with Western blot.RESULTS: Primary retinal microglia in culture exposed to LPS to induce microglia activation. Pretreatment with HCT significantly inhibited the LPS-induced cell proliferation, but not the cell viability. LPS induced inflammatory reaction in microglia and cell migration. HCT significantly reduced LPS-stimulated release of pro-inflammatory factors and decreased the number of migrating cells substantially in a concentration-dependent manner. Moreover, the protein levels of p-p38 MAPK were identified as the up regulation and co-treatment with HCT obviously inhibited the upregulation of p-p38 MAPK, but had no effect on the levels of total p38-MAPK.CONCLUSION: The data suggest that HCT inhibits LPSinduced retinal microglial activation via suppression of the p-p38-MAPK. HCT may be used for the treatment of ocular diseases characterized by over-activated microglia.

<i>Houttuynia cordata</i>Thunb: A Review of Phytochemistry and Pharmacology and Quality Control

Houttuynia cordata Thunb is an important medicinal plant widely distributed in East Asia. The collected information is an attempt to cover recent developments in the pharmacology, phytochemistry and quality control of this species. During the past several decades, the medicinally important phyto-constituents have been identified including essential oil, flavonoids and other polyphenols, fatty acids and alkaloids. A survey of the literatures shows H. cordata possesses a variety of pharmacological activities including antiviral, antitumor, antimicrobial, anti-inflammatory, and antioxidative effects. Little attempt has been done to review the techniques used for its quality control. Future efforts should concentrate more on in vitro, in vivo studies and clinical trials in order to confirm traditional wisdom in the light of a rational phytotherapy. The information summarized here is intended to serve as a reference tool to practitioners in the fields of ethnopharmacology and natural products chemistry.

Phenolics and Antioxidant Activities of Houttuynia cordata Thunb.

[Objectives] To evaluate the phenolic components of Houttuynia cordata Thunb. and their antioxidant activities from different sources. [Methods] Samples of 35 different sources of H. cordata were collected from Guizhou,and polyphenols,total flavonoids,total chlorogenic acid and 7 kinds of flavonoids( xanthol-3-O-glucoside,hyperoside,quercitrin,rutin,quercetin,kaempferol and isorhamnetin),and DPPH free radical scavenging rate of the extracts were determined. Relationship between the contents of phenolics and the DPPH free radical scavenging rate of the extracts were analyzed by SPSS software. [Results] There were some significant differences in polyphenols,total flavonoids,total chlorogenic acid and the seven flavonoids between samples of different habitats,and the contents of polyphenols,total flavonoids and total chlorogenic acid increased linearly with altitude. There was a significant positive correlation between polyphenols,total flavonoids and total chlorogenic acid content and DPPH free radical scavenging rate of extracts. The contents of kaempferol-3-O-glucoside,hyperoside,quercitrin,rutin,quercetin kaempferol and isorhamnetin were positively correlated with the DPPH free radical scavenging rates of the extracts,except for the significant correlation with quercitrin. [Conclusions]The experimental results suggest that the antioxidant capacity of H. cordata is derived from the total contribution of the phenolic components,indicating that these components have overall equivalence of antioxidant capacities. This provides a new research idea for solving the key problems of quality control of traditional Chinese medicine.

Determination of Total Flavonoids and Its Antioxidant Ability in Houttuynia cordata

The total flavonoids of Houttuynia cordata are determined by UV-Vis spectrophotometry. The ex-traction condition of flavonoids from Houttuynia cordata includes: the extraction temperature is 70℃, solid-liquid ratio is 1:20, solvent is 80% ethanol, extraction time is 65 min. We studied the antioxidation of flavonoids in Houttuynia cordata, and results showed that flavonoids had strong reducing capacity, hydroxyl free radical scavenging activity and the superoxide anion radical scavenging ability, thus can provide a basis for the development of natural antioxidants.

Analysis of Amino Acids in Houttuynia Cordata Thunb. by High Performance Liquid Chromatography-Diode Array Detector (HPLC-DAD)

[Objectives] The biologically active compounds of Houttuynia cordata Thunb. as a medicinal and edible plant are well documented. However, amino acid as an important indicator of the value of H. cordata is little reported. [Methods] Amino acids of the H. cordata were analysed by pre-column derivatization with 2,4-dinitrochlorobenzne(CDNB) coupled to HPLC/DAD. The optimized conditions of the amino acids derivatized by CDNB were followed: 110 ℃ of hydrolysis temperature, 1∶12 of the equivalent proportion between amino acid and CDNB, 80 min of derivatization reaction time and 80 ℃ of derivatization reaction temperature. The method was used to determine the amino acids of H. cordata samples from 11 different geographical sites in Guizhou. [Results] The results suggested that the contents of 17 amino acids were quite variable at different H. cordata samples. [Conclusions] This study will provide a basis for the quality evaluation of H. cordata nutrition.

Primary Research on Protective Effect of Houttuynia cordata Flavonoid and Sophora japonica L. Polysaccharide as Anti-UV Sun-screening Supplement

Houttuynia cordata flavonoid and Sophora japonica L. polysaccharide were investigated to develop anti-UV sun-screening agent through UV wavelength scanning spectrum, antioxidant ability and cell viability after UVB irradiation. The results showed that the extracts had strong UVA and UVB absorption ability and hydroxyl free radical scavenging ability. The S. japonica L. polysaccharide showed strong anti-UVB irradiation ability according to the cell viability experiment. It suggests that the H. cordata flavonoid and S. japonica L. polysaccharide could be combined as a candidate of anti-UV sun-screening supplement and compensate for the shortcomings of chemical sunscreens against UVA ray.

CLINICAL OBSERVATION ON 278 CASES OF BROCHIECTASIC HEMOPTYSIS TREATED BY POINT INJECTION OF HOUTTUYNIA SOLUTION

we treated 278 cases of bronchiectasic hemoptysis with point injection ofHerba Houttuynia solution.The injected points,among which Kongzui(LU6)was the mainpoint,were selected according to the differentiation of syndromes.As a result,217 caseswere improved,40 markedly cured ,40 markedly improved.12 improved and 9 not improved.The total effective rate reached 95.5%.

Establishment of Cytokines Quantitative PCR Methods and Its Application in Anaphylaxis Study of Houttuynia Cordata Injection

We design specific primers, according to the four kinds of important macaque cytokines, based on macaque β-action genes, then extract total RNA in peripheral blood mononuclear cells of macaques, and trascriptase cDNA reversely after establishing real-time quantitative PCR, and test the relative expression amount of several kinds of important cytokines during the hypersensitive process. The testing method of quantitative PCR in this experiment is highly sensitive, all cytokines are up to 102 copies/μL and highly reproducible, the intraassay and interassay coefficients of variation are less than 6%. The method applied to the sensitive reaction experiment on cytokines induced by houttuynia cordata turns out that the cytokines relative expression of houttuynia cordata distillate with low dose group and high dose group is significantly higher than that of saline group (P > 0.01). Meanwhile, significantly increased IL-4, IL-10 and IL-13 and decreased IFN-γ are found in both group A and group B after houttuynia injection (P > 0.05).

Houttuynia cordata Thunb rescues retinal ganglion cells through inhibiting microglia activation in a rat model of retinal ischemia-reperfusion

AIM:To determine whether Houttuynia cordata Thunb(HCT)can increase the survival of the retinal ganglion cells(RGCs)and inhibit microglia activation following retinal ischemia-reperfusion(RIR)injury.METHODS:Rat model of RIR was induced by transient elevation of the intraocular pressure(IOP).HCT was orally administered for 2 d before the performance of retinal RIR model and once a day for the next 14 d.After 14 d of RIR injury,the rats were sacrificed for further analysis.Survival RGCs were stained with haematoxylin and eosin(H&E).Apoptosis of RGCs was detected by TUNEL staining.Retinal function was examined by flash-electroretinography(F-ERG).Retinal microglia were labeled using Iba-1,one specific marker for microglia.The m RNA expression levels of inducible nitric oxide synthase(i NOS),tumor necrosis factor alpha(TNF-α),and interleukin 1 beta(IL-1β)were assessed by quantitative real time reverse transcription polymerase chain reaction(q RT-PCR).RESULTS:Systemic HCT treatment significantly reduced RGCs death by H&E staining and exhibited an anti-apoptotic effect as assessed by TUNEL staining at day 14 after RIR injury.HCT greatly improved the retinal function as examined by F-ERG.The number of activated microglia significantly increased after RIR injury,which was significantly attenuated by HCT treatment.Besides,RIR injury induced a strong upregulation of pro-inflammatory genes TNF-α,i NOS and IL-1βm RNAs at day 14 post injury,which was suppressed by HCT.CONCLUSION:Neuroprotective effects of HCT encourage the survival of RGCs through inhibiting microglia activation due to RIR injury.Together these results support the use of HCT as promising therapy for the ischemic events of the retina diseases.

Responses of Houttuynia cordata Thunb.to Tetracycline Stress

[Objectives]To study responses of Houttuynia cordata Thunb.to tetracycline(TC)stress in a sterile environment.[Methods]Aseptic H.cordata seedlings were cultured in the medium which added the different concentrations of TC,and then the contents of chlorophyll and malondialdehyde(MDA),and activity of catalase(CAT),peroxidase(POD)and superoxide dismutase(SOD)of H.cordata leaves were measured.[Results]Compared with the CK,the contents of chlorophyll of H.cordata leaves decreased,and the accumulation of MDA,and the activity of CAT,POD and SOD in H.cordata leaves increased when H.cordata was stressed by different concentration of TC.[Conclusions]The growth,metabolism and physiology of H.cordata were affected by the stress of TC.More importantly,this proved an insight into the effect or harm of undegraded antibiotics in the soil and water in the natural environment to plant growth all the time.

Study on the Effect of Aqueous Extract of Houttuynia cordata on Serum TNF-αand IL-6 Content in Mice Infected with Five Common Pathogenic Bacteria

[Objectives]To observe the effect of aqueous extract of Houttuynia cordata on the content of serum TNF-αand IL-6 in mice with abdominal infection caused by Staphylococcus aureus,Escherichia coli,Pseudomonas aeruginosa,Proteus vulgaris and Klebsiella pneumoniae,so as to investigate the antibacterial effect of aqueous extract of Houttuynia cordata in vivo.[Methods]A total of 72 KM mice were randomly divided into six groups:model group,blank group,cefdinir dispersible tablet group(0.25 g/kg),high,medium and low dose groups of aqueous extract of Houttuynia cordata(40,20,10 g/kg crude drug).There were 12 mice in each group,half male and half female,continuously given intragastric administration for three days,once a day.The blank group and the model group were intragastrically infused with normal saline,and the other groups were given corresponding drugs with a volume of 0.02 mL/g.After 30 min of administration on the third day,the mice were injected intraperitoneally with 0.5 mL of bacterial suspension to make bacterial infection.The mice in the blank group were intraperitoneally injected with the same amount of normal saline,followed by intragastric administration 6 h after intraperitoneal injection and intragastric administration again after 24 h.The mice were observed for three days,and the changes of body weight before and after infection were recorded.On the fourth day of infection,eyeball blood was taken,serum was separated,and the concentration of inflammatory factors TNF-αand IL-6 in serum was determined.[Results]Compared with the model group,the high,medium and low dose groups of H.cordata aqueous extract had protective effects on mice with abdominal infection caused by S.aureus,E.coli,P.aeruginosa,P.vulgaris and K.pneumoniae,and decreased the content of TNF-αand IL-6 in serum.[Conclusions]The aqueous extract of H.cordata had a certain antibacterial effect on acute abdominal infection caused by S.aureus,E.coli,P.aeruginosa,P.vulgaris and K.pneumoniae,and its mechanism was related to TNF-αand IL-6.

Effects of Climate Factors in Greenhouses on the Growth Development and Quality of Houttuynia cordata Thunb.

[Objectives]This study was conducted to demonstrate whether greenhouse planting can solve the problem of insufficient supply of fresh H.cordata Thunb.in winter and spring.[Methods]The effects of meteorological factors on the growth and quality of H.cordata Thunb.were analyzed.[Results]The highest temperature and lowest temperature in greenhouses were 6-12℃and 5-10℃higher than those in the open fields,respectively,and the average temperature difference between the greenhouses and the open fields was large in the early stage,but small in the late stage.The effective accumulated temperature≥10℃was 3463℃in the greenhouses and 2046℃in the open fields.Although the humidity in the open fields was higher than that in the greenhouses,the humidity in the greenhouses was relatively stable and that in the open field changed greatly.The light intensity of the greenhouses was lower than that of the open fields.In terms of the periods from film covering day to seedling emergence,seedling emergence to full emergence,and full emergence to crop closure,greenhouse planting was shortened by 47,11,and 5 d,respectively,compared with open field planting,but the period from crop closure to flowering was extended by 40 d.The plant height of the plants planted in the greenhouses reached 0.1 cm on January 7,while those planted in the open fields did not have seedlings until February 25,and the plant height,daily growth rate,yield and effective components in volatile oil of the plants planted in the greenhouses were significantly higher than those planted in the open fields.The growth,development and quality of H.cordata Thunb.reached the extremely significant or significant level with temperature,but had no significant correlation with humidity and light intensity,indicating that temperature had the greatest impact on the growth,development and quality of H.cordata Thunb.when planted in the greenhouses.[Conclusions]This study provides a theoretical basis for protected cultivation and explores new planting methods for the further development of its industry.

Network pharmacology-based analysis on three amicoumacin-type isocoumarin compounds from an endophytic bacterium in Houttuynia cordata

Amicoumacin isocoumarin-type compounds are mainly derived from the secondary metabolites of Bacillus bacteria,and have potential biological activities such as antibacterial,anti-tumor,anti-inflammatory,and anti-ulcer.In our previous research,three amicoumacin-type isocoumarin compounds,Paenicoumacin A,Paenicoumacin B,and Paenicoumacin C(B and C are novel),were isolated from an endophytic bacterium in Houttuynia cordata.In this study,network pharmacology and bioinformatics techniques were used to analyze the potential activities of amicoumacin compounds in the treatment of liver cancer.These compounds were found to mainly regulate cellular oxidative stress,cancer process,nucleic acid metabolism,nutritional metabolism and other pathways.The findings provide useful information for subsequent experimental verification.

Mining potential adverse drug reactions of Houttuynia cordata Thunb from "real world" cases

Objective: Search the "real world" case reports of Houttuynia cordata Thunb (HCT)-associated adverse drug reactions (ADRs) to systematically mine potential ADRs of HCT and further investigate whether HCT contained preparations could cause aristolochic acid nephropathy or cancer. Methods: PubMed, EMBASE, Science Direct, Scopus, Web of Science, and CNKI, Wanfang, VIP, Sinomed databases were searched from databases setup to 1st January 2019. All case reports using HCT contained preparations were pooled according to inclusion and exclusion criteria. 15 items in case reportes including basic informations of studies/patients, characters/treaments of ADRs were extracted and analyzed. Results: A total of 346 case reports (441 patients) on the use of different preparations of HCT were finally pooled, among which 89 articles (117 patients) just presented efficacy reports without ADRs and 257 articles (324 patients) on the HCT-related ADRs were further analyzed.① HCT in vivo injections were recorded in 265 articles (338 patients) including 249 ADR reports (315 patients) and 16 efficacy reports (23 patients). As for the ADRs reports, allergic reaction was the major ADRs with different symptoms and onset time. The worst consequences were anaphylactic shock (116/315) and death (11/315), followed by dyspnea (228/315), change of complexion (181/315), heart of abnormality (180/315), chest tightness (147/315), cyanosis (142/315) and so on. The fast onset time was 10 seconds and the most ADRs happened in 30 minutes. Dexamethasone was the mainly medication to treat ADRs.② Oral HCT agents were descripted in 75 articles (94 patients) including 8 ADR reports (9 patients) and 67 efficacy reports (85 patients). Among the 8 ADR reports, 8 patients used Chinese patent medications contained HCT and only 1 patient used HCT decoction. The ADRs almost manifested as skin symptoms, including rubella, macula, rash and urticaria.③ HCT external preparations reported in 6 articles (9 patients), none of those presented any ADRs symptoms.④ No case was found to develop cancer, aristolochic acid nephropathy, interstitial nephritis, renal interstitial fibrosis or renal failure due to HCT preparations. Conclusion: The HCT-related ADRs were mostly caused by its processed preparations, including HCT injections and patent preparation. The oral HCT agents as docoction rearly caused ADRs. There were no reports of aristolochic acid nephropathy or cancer cases caused by HCT.

Effects and safety of Chinese herbals containing Houttuynia cordata Thunb in the treatment of lung cancer:a systematic review

Objective:This study systematically evaluates the efficacy and safety of Houttuynia cordata in the treatment of lung cancer in order to provide clinical data support for better application of Houttuynia cordata.Methods:PubMed,EMbase,Web of Science,ScienceDirect,Scopus,CNKI,WanFang Data,VIP and SinoMed were used to retrieve clinical observations and clinical controlled studies of Houttuynia cordata in the treatment of lung cancer.The retrieval time ranges from database building to January 2019.Two researchers independently screened literature,extracted data and conducted computational analysis.Result:In the clinical observational study,12 literatures of pure Chinese medicine treatment(1473 patients)and 4 literatures of combined Chinese and Western medicine treatment(193 patients)were compared.The total effective rate and total stable rate of combined Chinese and Western medicine treatment for tumour control were better,but the total improvement rate of quality of life of combined Chinese and Western medicine treatment was lower than that of pure Chinese medicine,and the incidence of adverse reactions such as bone marrow suppression and gastrointestinal tract reaction was also higher than that of pure Chinese medicine.Chinese medicine In the clinical control study,8 articles(567 patients)in the treatment group were treated by Chinese medicine and 9 articles in the treatment group(530 patients)were treated by combination of Chinese and Western medicine.Compared with Chinese medicine group,the total effective rate and total stability rate in the control of tumor size were higher in the combination of Chinese and Western medicine;The survival rate of 0.5~2 years was higher,and the total effective rate of body weight gain was slightly higher in the combination of Chinese and Western medicine.At the same time,the incidence of side effects was significantly higher than that of pure Chinese medicine treatment group.In addition,compared with the control group,the incidence of all side effects in the pure Chinese medicine group was lower.Compared with the control group,besides"bleeding","oral reaction"and"skin reaction",the probability interval of side effects in the treatment group was less than that in the control group,and the degree of side effects was also less than that in the chemotherapy group.Conclusion:In the treatment of lung cancer,the use of herbs containing Houttuynia cordata combined with western medicine or radiotherapy and chemotherapy not only has good curative effect,but also reduces toxicity and side effects.Therefore,the combination of herbs with western medicine has unique advantages,which deserves further in-depth research and development.

Study on Underground Stem Tissue Structure and Agronomic Traits of Different Populations of Wild Houttuynia cordata Thumb

[Objectives] To study the underground stem tissue structure and agronomic traits of different populations of wild Houttuynia cordata Thumb. [Methods] 8 different populations of wild Houttuynia cordata Thumb. in southern China were selected,the preliminary study was carried out about underground stem tissue structure( stem wall thickness,underground stem cross section diameter,medullary cavity,large vascular bundle area,small vascular bundle area,and number of vascular bundles),and main agronomic traits of aboveground and underground parts. [Results]There were significant differences in the underground stem tissue structure and agronomic traits of some populations of wild Houttuynia cordata Thumb. [Conclusions] From comparison,it reached the conclusion that the populations of wild Houttuynia cordata Thumb. in Kunming of Yunnan,Hechuan of Chongqing,and Nanning of Guangxi showed better underground stem tissue structure and agronomic traits. The results are expected to provide certain guidance for cultivation,reasonable development,and utilization of wild populations of Houttuynia cordata Thumb.