Control of In Vitro Regeneration of Individual Reproductive and Vegetative Organs in Dracaena fragrans cv. massangeana Hort. Regularities of the Direct Regenerationof Individual Organs In Vitro

Various individual organs (tepal, flower bud, inflorescence branch, inflorescence, adult vegetative bud and juvenile vegetative bud) were directly regenerated respectively by callus in Dracaena fragrans cv. massangeana Hort. During the regeneration of these individual organs some regularity phenomena were observed. Firstly, the kind range of the individual organs, which are directly regenerated in vitro, is in close relationship to the differentiated stages of the organs used for explant excision during plant ontogeny. The explants excised from the epigeous organ that is differentiated at some stage (stage A) during plant ontogeny must be able to separately regenerate all of those individual epigeous organs: ones differentiated slightly later than the stage A, ones differentiated at the stage A and all ones differentiated earlier than the stage A. Secondly, within this range which kind of organ is regenerated depends on the exogenous auxin concentrations in medium. With the gradual increase of 2,4-D concentration from 0.005 mg/L to 0.5 mg/L, the kinds of regenerated organs will change by the order as follows: vegetative bud, inflorescence, inflorescence branch, flower bud, tepal. These regularities will be able to be used for inducing the direct regeneration of a given epigeous organ in angiosperms.

Direct Regeneration of Inflorescence from Callus in Dracaena fragrans cv. Massangeana Hort.

以花叶千年木 (Dracaenafragranscv .MassangeanaHort.)的花被筒、花序分枝轴和花序轴为外植体成功地诱导了花序的直接再生。3种外植体首先在MS附加 1.0mg L 6_BA和 0 .5_0 .8mg L 2 ,4_D的培养基上诱导形成愈伤组织 ,然后转移到MS附加 0 .5mg L 6_BA和 0 .0 0 5～ 0 .5mg L 2 ,4_D的培养基上分别诱导了花序的直接再生。

Identification and rDNA-ITS Sequence Analysis of a New Anthracnose Pathogen of Dracaena fragrans in Yunnan Province

In this study, identification and rDNA-ITS sequence analysis of an anthracnose pathogen on Dracaena fragrans were carried out. [Method] D. fra-grans leaves with lesions were used as experimental materials to isolate anthrac-nose pathogen. Morphological observation, rDNA-ITS amplification and sequence analysis were performed to identify the pathogen strain. [Result] Caonidia of the iso-lated anthracnose pathogen were straight or curved, el iptic to crescent, with 2-5 oil droplets, 7.5-20 × 4.5-5 μm. According to molecular phylogenetic analysis, the iso-lated pathogen strain was identified as a new species, which was named Col-letotrichum dracaena-fragrantis sp. nov. [Conclusion] This study provided theoretical basis for the prevention and control of anthracnose.

Dracaenoside A and B, New C-22 Steroidal Lactone Glycosides from the Stem of Dracaena cochinchinensis

Two new C-22 steroidal lactone glycosides, named dracaenoside A and B were isolated from the methanol extract of the fresh stem of Dracaena cochinchinensis. Their structures were established as (20S)3b,14a,16b-trihydroxy pregn-5-ene-22-carboxylic acid (22,16)-lactone 3-O-a- L-rhamnopyranosyl (1→2)[ a-L-rhamnopyranosyl (1→4)]-b-D-glucopyranoside and (20S)3b, 14a, 16b-trihydroxy pregn-5-ene-22-carboxylic acid (22,16)-lactone 3-O-a-L-rhamnopyranosyl (1→2) [b-D-glucopyranosyl(1→3)]-b-D-glucopyranoside by means of 2D NMR spectral and chemical methods. It is the first time that steroidal lactone glycosides were isolated from the genus Dracaena.

Larvicidal efficacy of crude and fractionated extracts of Dracaena loureiri Gagnep against Aedes aegypti, Aedes albopictus, Culex quinquefasciatus, and Anopheles minimus mosquito vectors

Objective:To evaluate the larvicidal efficacy of crude and fractionated extracts of Dracaena loureiri endocarp against Aedes aegypti,Aedes albopictus,Culex quinquefasciatus,and Anopheles minimus mosquitos.Methods:Larvicidal activity was tested according to World Health Organization standard protocol.The third-stage larvae of each mosquito species were exposed to various concentrations of Dracaena loureiri crude extract and six groups of Dracaena loureiri fractionated extracts(RC-DT 009-014).Larval mortality rates were observed after 24 h and48 h of exposure.Then,a computerized probit analysis of the mortality data was performed to determine lethal concentration 50(LC_(50))and lethal concentration 90 values.Results:Anopheles minimus larvae(24-h LC_(50)77.88 mg/L)had the highest susceptibility to crude extract,whereas others(Aedes aegypti,24-h LC_(50)224.73 mg/L;Aedes albopictus,24-h LC_(50)261.75 mg/L;and Culex quinquefasciatus,24-h LC_(50)282.86 mg/L)were significantly less susceptible.The most effective groups of fractionated extracts were RC-DT 012 and RC-DT 013.The mosquito species most susceptible to fractionated extracts was Culex quinquefasciatus,with 24-h LC_(50)values of 0.66 and 0.94 mg/L for RC-DT 012 and RC-DT 013,respectively.Conclusions:The larvicidal activity of fractionated extracts is more effective than that of crude extract against all tested mosquito species.For the most effective alternative larvicide,purification and a phytochemical constituent analysis must be performed.

Flavonoid oligomers from Chinese dragon’s blood,the red resins of Dracaena cochinchinensis

A detailed chemical investigation of the red resins from Dracaena cochinchinensis(Chinese dragon’s blood)yielded five new flavonoid oligomers,named cochinchinenins D-H(1-5),together with a known biflavonoid,cinnabarone(6),and a mixture of two known biflavonoids,socotrin-4'-ol(7)and homoisosocotrin-4'-ol(8).Of these new compounds,1-3 were biflavonoids and 4 and 5 were triflavonoids.Their structures were determined on the basis of spectroscopic analysis.The isolated compounds were tested for cytotoxicity(Cdc25),antibacterial(PEPT)and antifungal(YNG)activities.

Effects of Dracaena arborea(Dracaenaceae) on sexual dysfunction in 4 weeks hyperglycemic male rats

Objective:To investigate the effects of Dracaena arborea(D.arborea) on the sexual behavior parameters in experienced type-1 diabetic rats.Methods:Aqueous and ethanol(100 and 500mg/kg respectively)extracts of dried root barks of D.arborea.sildenafil citrate(1.44 mg/kg),trimethylamine-N-oxide(TMAO,20 mg/kg)and distilled water(110 mL/kg.were orally administered to 4 weeks streptozolocin-induced diabetic rats.Mount latency and frequency(ML.MF),intromission latency and frequency(IL,IF) and post-ejaculatory interval(PEI) were measured by ejaculating series during 90 min once a week for 4 weeks.Glycemia was determined at the beginning and at the end of the treatment Results:D.arborea did not show any major antihvperglycemic effects.Compared to the control group,a significant(P<0.05-0.001)increase in MF and IF was noticed in rats treated with sildenafil citrate(89.71% and 90.07% respectively),aqueous(500 mg/kg.88.08%and 88.749;respectively) and ethanol(100 mg/kg;89.53%and 89.17respectively) extracts of D.arborea after two weeks(series 1) of treatment.ML,IL and PEI were significantly(P<0.05-0.001) decreased after 4 weeks of daily treatment[sildenafil citrate(96.31.96.31%and 34.98%),and D.arborea aqueous 500 mg/kg(94.33.94.33% and 66.609;i and ethanol extracts 100 mg/kg(96.98.97.089;and 64.26%)].Conclusions:These aphrodisiac potentials of D.arborea in experienced diabetic rats could be due to the antioxidant and androgenic properties of phenols,flavonoids.saponins and sterols revealed in the plant extracts.

Larvicidal activity of endocarp and seed crude extracts of Dracaena loureiri Gagnep against Aedes aegypti(L.) mosquito

Objective: To evaluate the larvicidal activity of the ethanolic and aqueous extracts of the endocarp and seeds of Dracaena loureiri(D. loureiri) against the dengue mosquito vector, Aedes aegypti.Methods: Bioassays were performed by exposing late third-stage to early fourth-stage larvae of Aedes aegypti to various concentrations of the extracts from D. loureiri. The larval mortality was observed after 24-and 48-h exposure.Results: The larvicidal bioassay in this study demonstrated that the ethanolic endocarp extract was the most effective with the LC50 value of 84.00 mg/L after 24 h exposure and< 50 mg/L after 48 h exposure. Extracts from the other parts of the plant were significantly less effective as a larvicide.Conclusions: The ethanolic endocarp extract of D. loureiri demonstrated effective larvicidal activity. It is an alternative source for developing a novel larvicide for controlling this mosquito species.

Effects of the Incorporation of <i>Dracaena arborea</i>Roots Powder on Growth Performance and Some Haematological Parameters in Guinea Pigs (<i>Cavia porcellus</i>)

The present study was assigned to evaluate the Effect of Dracaena arborea roots powder in ration on growth performances and some hematological parameters in the guinea pig on diet supplemented with graded levels of incorporation. A total of 40 guinea pigs weaned of local breed and aged 3 weeks were divided into 4 identical batches. Each of the groups was randomly assigned one of 4 rations containing different levels of the powder from Dracaena arborea (Da) roots: Da0;Da0.25;Da0.5 and Da0.75. The results at the 11th week of breeding showed that the highest intake (21.13 g/d) was obtained with the Da0.5 ration. The highest live weight (372.50 g) and total weight gains were obtained with the Da0.25 ration. In addition, the highest commercial (161.75 g) and conventional (307.75 g) carcass weights and large intestine length (99.5 cm) were obtained with the D0.25 ration. The highest values for granulocytes (0.250.103/μl), platelets (805.103/μl) and lymphocytes (6.92.103/μl) were respectively, obtained with the rations containing Da0;D0.5 and D0.75. In view of the above, Dracaena arborea roots powder can be used at a rate of 0.25% in the ration, to improve the productivity of the guinea pig (Cavia porcellus).

Examining the Effect of Hydroalcoholic Extract of Dracaena cinnabari on Sex Hormones and Ovarian and Uterine Tissues of Rats

Introduction: Dracaena cinnabari is considered a rich source of phytochemicals used widely in traditional medicine. In the present study, the effect of D. cinnabari hydraulic extract on the reproductive system of female rats was investigated. Methods: The samples were randomly divided into four groups(six samples in each group), including three treatment groups and one control group, and all samples were kept at the same conditions. Hydraulic extract of D. cinnabari and injected intraperitoneally daily for 10 days, while physiological serum was used for injection in to the control group. After 10 days of injection, estrogen and progesterone levels were measured by enzyme immunoassay technique. After dissection, the ovaries and uterine tissues were isolated for histological examination, and tissue changes were carefully examined. Results: The results revealed that the levels of estrogen and progesterone in experimental Groups 2 and 3 had a significant increase(P < 0.001). Regarding tissue changes, a significant increase was observed in epithelial thickness(P < 0.001), number of corpus luteum(P < 0.01), and Graafian follicle(P < 0.01) in doses of 100 and 150 mg/kg. Conclusions: Based on the results, it seems that D. cinnabari extract has an effect on the ovarian follicles.

Transient receptor potential vanilloid 1 involved in the analgesic effects of total flavonoids extracted from Longxuejie(Resina Dracaenae Cochinchinensis)

OBJECTIVE: To evaluate the analgesic effects of total flavonoids of Longxuejie(Resina Dracaenae Cochinchinensis)(TFDB) and explore the possible analgesic mechanism associated with transient receptor potential vanilloid 1(TRPV1).METHODS: Whole-cell patch clamp technique was used to observe the effects of TFDB on capsaicin-induced TRPV1 currents. Rat experiments in vivo were used to observe the analgesic effects of TFDB. Western blot and immunofluorescence experiments were used to test the change of TRPV1 expression in DRG neurons induced by TFDB.RESULTS: Results showed that TFDB inhibited capsaicin-induced TRPV1 receptor currents in acutely isolated dorsal root ganglion(DRG) neurons of rats and the half inhibitory concentration was(16.7 ± 1.6) mg/L.TFDB(2-20 mg/kg) showed analgesic activity in the phase Ⅱ of formalin test and(0.02-2 mg per paw)reduced capsaicin-induced licking times of rats. TFDB(20 mg/kg) was fully efficacious on complete Freund's adjuvant(CFA)-induced inflammatory thermal hyperalgesia and capsaicin could weaken the analgesic effects. The level of TRPV1 expressions of DRG neurons was also decreased in TFDB-treated CFA-inflammatory pain rats.CONCLUSION: All these results indicated that the analgesic effect of TFDB may contribute to their modulations on both function and expression of TRPV1 channels in DRG neurons.

柬埔寨龙血树褐斑病的病原鉴定及其培养条件分析

[目的]柬埔寨龙血树为我国各省市广泛栽培的室内观叶植物,近年来普遍发生叶部病害影响其观赏价值。2011年8月至2016年12月,在云南省蒙自市、新疆乌鲁木齐的柬埔寨龙血树发现一种叶部初期褪绿逐渐变为灰褐色凹陷最后暗褐色枯死的褐斑病。为了确定其病原菌种类和发病条件,进行病原菌鉴定及培养条件测试。[方法]采用在云南蒙自、新疆乌鲁木齐采集的12份柬埔寨龙血树褐斑病病叶,开展了组织分离、致病性测试、形态学观察、分子鉴定与培养条件测试。[结果]从12份病叶分离到15株真菌,菌落中央产生黑色孢子,边缘白色,顶囊球形或近球形,直径38~45μm,分生孢子球形暗褐色,直径2~5μm,代表性菌株LZB-6、LZB-12经CaM或β-tubulin系统发育分析确定为塔宾曲霉;刺伤法接种14 d的龙血树叶片均发病,症状与田间一致,并能分离到菌落形态、分生孢子形态与原分离菌株一致的真菌,完成科赫法则验证确定为病原菌。培养条件测试表明,病原菌菌丝生长的适宜温度为22~34℃,最适宜温度为28℃,光照抑制菌丝生长,菌丝生长偏爱碱性环境,pH为7~10时,随着pH值升高生长速率仍在增加,最适宜碳源和氮源分别为甘露醇、明胶,菌丝致死温度为55℃10 min;产孢适宜温度为28~40℃,最适宜温度为32℃,光照抑制产孢,适宜产孢pH值为6~8,最适宜pH值为8,最适宜碳源和氮源分别为蔗糖、明胶,孢子的致死温度为60℃10 min。[结论]导致云南蒙自、新疆乌鲁木齐的柬埔寨龙血树褐斑病菌均为塔宾曲霉,除了光照和氮源之外,温度、pH值、碳源对菌丝生长和产孢的影响均不同,22~34℃时病原菌能较好的生长与产孢,应加强对柬埔寨龙血树褐斑病的防控。

靖西珍稀药用植物剑叶龙血树(Dracaena cochinchinensis)生态解剖研究

以广西靖西珍稀药用植物剑叶龙血树(Dracaena cochinchinensis)为材料,采用光学显微镜及电镜扫描技术,研究其营养器官的解剖结构特征。结果表明:其叶为等面叶,上下表皮均有气孔器分布并具较发达的角质膜,下表皮气孔较多、孔下室发达且角质膜多具乳突状疣体,上下表皮内方都均匀分布成束的机械组织,侧脉中木质部与韧皮部呈横向平列关系。老根由发达的栓化层、皮层和维管柱组成;且皮层薄壁组织中散生大量次生周木维管束。老茎的结构由外至中央依次为栓化层、皮层、形成层及散布有维管束的基本组织;在基本组织中的初生外韧维管束散布在近茎中央的基本组织中,次生周木有限维管束则在形成层与初生维管束之间散布,皮层中无维管束分布。产于广西靖西的剑叶龙血树其营养器官的解剖结构与岩溶石山的干旱、高温和瘠薄的生态环境相适应,体现了结构与功能的统一。

HPLC-ESI-MS Analysis of Flavonoids Obtained from Tissue Culture of Dracaena cambodiana

Dragon＇s blood is a traditional medicine and used in many countries with different cultures because of its various therapeutic properties. The main bioactive constituents of dragon＇s blood are flavonoids, which exhibit various pharmaceutical activities, such as haemostatic, analgesic, anticoagulant, and antimicrobial activities and so on, and have attracted the attention of researchers on the development of new drugs. However, the formation process of dragon＇s blood in nature is very slow, which cannot meet the demand of pharmaceutical uses. Dracaena cambodiana （D. cambodiana） is one of the resource plants of dragon＇s blood na, 6-benzylaminopurine was added in the medium, then red During the course of tissue culture of D. cambodiasecretion was discovered in the cultured medium. Twelve compounds（1--12）, including 11 flavonoids, were determined via the analysis of constituents of the cultured medium by high performance liquid chromatography-electrospray ionization-mass spectrometry（HPLC-ESI-MS） and the results were compared with that of the standards isolated from dragon＇s blood. Among compounds 1-12, 4,4＇- dihydroxy-2-methoxydihydrochalcone（5）, 4,4＇-dihydroxy-2,6-dimethoxydihydrochalcone（6） and （2S）-7,3＇-dihydroxy- 4＇-methoxyflavane（9） were major compounds of the red secretion, with contents of 15.70, 7.10 and 57.23 mg/L, respectively. Therefore, it is promising that flavonoids from dragon＇s blood can be obtained from the tissue culture of its resource plants for the purpose of drug development.

In vitro evaluation of antimicrobial and antioxidant activity of Dragon’s blood tree(Dracaena cinnabari Balf.f.)of Socotra Island(Yemen)

Objective:To evaluate the performance of preliminary phytochemical,antioxidant and antimicrobial activities of Dracaena cinnabari Balf.f.(Agavaceae)(D.cinnabari)resin,collected from Socotra Island(Yemen).Methods:The powdered stem resin is extracted with different solvents by using Soxhlet apparatus and evaluated for antioxidant and antimicrobial activity against three Gram positive bacteria(Bacillus cereus NCIM 2106,Staphylococcus aureus NCIM 2127,and Micrococcus luteus NCIM 2169),seven Gram negative bacteria(Escherichia coli NCIM 2924,Pseudomonas aeruginosa NCIM 2863,Salmonella typhimurium NCIM 2501,Klebsiella aerogenes NCIM 2281,Proteus morganii NCIM 2860,Escherichia coli dh5α,Escherichia coli CSH)and three fungi(Candida albicans MTCC 227,Aspergillus flavus MTCC 873,Aspergillus niger MTCC 1781).Results:The antimicrobial activity data revealed that,the selected microorganisms possess varied sensitivity response to chloroform extract followed by methanol and benzene extract of D.cinnabari stem resin.The samples also possess a potent DPPH,OH and SO radical scavenging activity.In addition,the preliminary phytochemical analysis demonstrated the presence of alkaloids,flavonoids,terpenoids and other organic compounds which could be reason for antimicrobial activities of D.cinnabari resin.Conclusions:The present study is strengthened for the discovery and development of new antioxidant and antimicrobial drugs from D.cinnabari resin which encourage us to continue with pure fractions.

不同水分条件对海南龙血树幼苗表型可塑性及生态适应性的影响

通过盆栽试验探讨濒危植物海南龙血树幼苗对水分响应的表型可塑性,分析其生态适应性。结果表明,海南龙血树幼苗对水分的响应主要在形态指标和生物量方面,除了比叶面积、叶片长宽比和株高外,其他指标均达到显著水平(P<0.05);生物量分配主要与根部性状相关,幼苗叶绿素和类胡萝卜素含量在各处理间无显著差异(P>0.05)。海南龙血树幼苗能够充分利用水分资源,在雨季快速生长,并将更多的生物量分配给根部,有利于度过雨季后严峻的干旱季节。海南龙血树幼苗对水分响应的生存策略具有很强的生态适应性。

龙血树组织诱导快速繁殖技术研究

【目的】探究不同消毒方法和激素配比对龙血树组培快繁技术的影响,为建立龙血树组培快繁体系提供参考。【方法】以‘太空’和‘68#’2个龙血树品种的外植体为试材,探讨不同的灭菌时间、激素配比及浓度对龙血树不定芽诱导、增殖和生根的影响。【结果】研究表明龙血树无菌材料的获得,适宜采用带顶芽茎段,先用75%酒精消毒20 s,再用0.1%升汞溶液消毒8 min,消毒效果最佳。MS+5.0 mg/L 6-BA+3.0 g/L花宝为最佳不定芽诱导培养基;MS+2.0 mg/L 6-BA+0.1 mg/L NAA为最佳增殖培养基,太空和68#增殖系数分别达5.35和4.87;MS+1.0 mg/L NAA为最佳生根培养基,太空和68#的生根率均高于99%,生根数分别达到9.2和11.2条。【结论】建立以带顶芽茎段为外植体的龙血树组织培养快繁体系,为龙血树工厂化生产和遗传转化等研究奠定良好基础。

Cochinchin from Dracaena cochinchinensis

A new compound, Cochinchin (1), together with 7,4'-dihydroxyflavone (2), 7-hydroxy-4'-methoxyflavane (3), 7-hydroxy-3-(4-hydroxybenzyl)chroman (4), 4'-hydroxy-2,4-dimethoxydihydrochalcone (5) and 4'-hydroxy-2,4,6- trimethoxydihydrochalcone (6) was isolated from the resin (trivial name, “dragon’s blood”) of Dracaena cochin- chinensis (Lour.) S. C. Chen. The structure of 1 was elucidated on the basis of spectroscopic data as (2,3-trans)-6-allyl-2-(3,5-dimethoxyphenyl)-3-(4-hydroxyphenyl)-2,3-dihydrobenzo[1,4]dioxin which is a natural product possessing a new framework.

A New Phenylpropanoid Glycoside from Dragon＇s Blood of Dracaena cambodiana

A new phenylpropanoid glycoside, named cambodianin F（1）, together with three known compounds, 1-O-β-D-glucopyranosyl-2-hydroxy-4-allylbenzene（ 2 ）, 1-O-（ 6-O-a-L-rhamnopyranosyl-β-D-glucopyranosyl）-2-hydroxy- 4-allylbenzene（3） and 1,2-di-O-β-D-glucopyranosyl-4-allylbenzene（4） was isolated from the dragon＇s blood of Dracaena cambodiana. The new compound was elucidated by HR-ESI-MS and spectroscopic techniques（UV, IR, 1D and 2D NMR）.

A chromosome-level genome assembly for Dracaena cochinchinensis reveals the molecular basis of its longevity and formation of dragon’s blood

Dracaena,a remarkably long-lived and slowly maturing species of plant,is world famous for its ability to produce dragon’s blood,a precious traditional medicine used by different cultures since ancient times.However,there is no detailed and high-quality genome available for this species at present;thus,the molecular mechanisms that underlie its important traits are largely unknown.These factors seriously limit the protection and regeneration of this rare and endangered plant resource.Here,we sequenced and assembled the genome of Dracaena cochinchinensis at the chromosome level.The D.cochinchinensis genome covers 1.21 Gb with a scaffold N50 of 50.06 Mb and encodes 31619 predicted protein-coding genes.Analysis showed that D.cochinchinensis has undergone two whole-genome duplications and two bursts of long terminal repeat insertions.The expansion of two gene classes,cis-zeatin O-glucosyltransferase and small auxin upregulated RNA,were found to account for its longevity and slow growth.Two transcription factors(bHLH and MYB)were found to be core regulators of the flavonoid biosynthesis pathway,and reactive oxygen species were identified as the specific signaling molecules responsible for the injuryinduced formation of dragon’s blood.Our study provides high-quality genomic information relating to D.cochinchinensis and significant insight into the molecular mechanisms responsible for its longevity and formation of dragon’s blood.These findings will facilitate resource protection and sustainable utilization of Dracaena.