Mo-based catalysts for CH4/H2S reforming to hydrogen production: effect of hydroxyl concentration of the support.

High concentration of H2S in acidic natural gas will lead to poisoning of catalysts for hydrogen production by methane steam reforming, thus limiting the further use of natural gas. Reforming CH4 by H2S can be considered as an alternative route to hydrogen production from methane. This process not only achieves the removal of H2S but also obtains chemical raw material CS2 and clean energy H2. By impregnating the Mo source on SiO2 treated with hydrogen peroxide and then using the catalyst in the CH4/H2S reforming reaction, we surprisingly found that the conversion rate of CH4 and H2S increased from 28 and 32% to 34% and 43%, respectively, after hydrogen peroxide treatment. The H2 production rate and the yield of CS2 increased from 20 mmolH2/(gMo*min) and 52% to 30 mmolH2/(gMo*min) and 65%, respectively. Combining with characterization methods such as X-ray diffraction (XRD), hydrogen temperature programmed reduction (H2-TPR), 1H-based solid-state nuclear magnetic resonance (1H MAS NMR), X-ray photoelectron spectroscopy (XPS), Raman spectra (RS), and transmission electron microscopy (TEM), we found that the hydroxyl concentration of the support increased after hydrogen peroxide treatment, which led to the strengthening of the force between the metal and the support, which was easy to form low-level and small-size MoS2, exposing more active sites, and further improving the catalytic activity. This method provides a new idea for hydrogen production by CH4/H2S reforming and the development of high-performance MoS2-based catalysts.

Integrating Target-Triggered Aptamer-Capped HRP@Metal-Organic Frameworks with a Colorimeter Readout for On-Site Sensitive Detection of Antibiotics.

Colorimetric analytical strategies exhibit great promise in developing on-site detection methods for antibiotics, while substantial recent research efforts remain problematic due to dissatisfactory sensitivity. Taking this into account, we develop a novel colorimetric sensor for in-field detection of antibiotics by using aptamer (Apt)-capped and horseradish peroxidise (HRP)-embedded zeolitic metal azolate framework-7 (MAF-7) (Apt/HRP@MAF-7) as target recognition and signal transduction, respectively. With the substrate 3,3',5,5'-tetramethylbenzidine (TMB)-impregnated chip attached on the lid, the assay can be conveniently operated in a tube and reliably quantified by a handheld colorimeter. Hydrophilic MAF-7 can not only prevent HRP aggregation but also enhance HRP activity, which would benefit its detection sensitivity. Besides, the catalytic activity of HRP@MAF-7 can be sealed through assembling with Apt and controllably released based on the bioresponsivity via forming target-Apt complexes. Consequently, a significant color signal can be observed owing to the oxidation of colorless TMB to its blue-green oxidized form oxTMB. As a proof-of-concept, portable detection of streptomycin was favorably achieved with excellent sensitivity, which is superior to most reported methods and commercial kits. The developed strategy affords a new design pattern for developing on-site antibiotics assays and immensely extends the application of enzyme embedded metal-organic framework composites.

Endophytic fungi, host genotype, and their interaction influence the growth and production of key chemical components of Dendrobium catenatum.

To examine how host plant genotype, endophytic fungal species, and their interaction may affect growth and key chemical content and composition in an important orchid species, we assessed four Dendrobium catenatum cultivars co-cultured with three fungi previously isolated from D. catenatum. Fungal endophytes (Tulasnella sp., Leptosphaeria microscopica, and Guignardia sp.) specifically affected the growth and chemical composition of the four cultivars. Fungal infection significantly increased certain growth traits, especially mid-stem thickness, stem biomass, stem polysaccharide and ethanol-soluble extractive content, and leaf flavonoid and phenol content. Presence or abundance of some key chemical components was also altered by fungal treatment. These increases and alterations were highly dependent on the host genotype. The findings of this study contribute to our understanding of Dendrobium and endophytic fungi interactions, and provide vital information for improving the development and use of endophytic fungi in D. catenatum breeding.

l-Pyroglutamic Acid-Modified CdSe/ZnS Quantum Dots: A New Fluorescence-Responsive Chiral Sensing Platform for Stereospecific Molecular Recognition.

Stereoselective recognition of amino acids is extremely important due to its high chirality-dependent interactions and physiological activities in life activities. We herein report a novel functionalized chiral fluorescent nanosensor prepared from surface modification of CdSe/ZnS quantum dots (QDs) with pyroglutamic acid derivatives, which could serve as a chiral recognition module for fluorescence detection of chiral molecules. The sensor exhibited a unique stereoselective fluorescence response to histidine (His), glutamate (Glu), and dihydroxyphenylalanine (Dopa) and had preferable response performance to l-enantiomers. The enantiomeric fluorescence difference ratios of His, Glu, and Dopa enantiomers were 3.90, 3.40, and 2.49, respectively. The mechanism for the enantiomeric fluorescence recognition was systematically studied through a fluorescence spectrum, fluorescence life, and density functional theory (DFT) calculation. Presumably, the different hydrogen bonding capacity of the chiral recognition module with two enantiomers mainly contributed to the difference in fluorescence signals. As a result, a broader application of the pyroglutamic acid derivative-coated QDs as a fluorescence-responsive chiral sensing platform for enantiomeric detection would be expected.

"Pomegranate-Like" Plasmonic Nanoreactors with Accessible High-Density Hotspots for in Situ SERS Monitoring of Catalytic Reactions.

Noble metal nanoparticles (NPs) have enabled surface-enhanced Raman scattering (SERS) for in situ monitoring of NPs-catalyzed reactions. However, it still remains a great challenge to ensure that analytes without plasmonic metal surface-affinity groups (such as thiol and amino groups) can be located into hotspots and detected by SERS. Here, we report a novel sacrificial template method for the fabrication of "pomegranate-like" plasmonic nanoreactors (PPNs), in which high-density embedded AuNPs simultaneously generated SERS enhancement and catalytic performance. Once the analytes entering PPNs are catalyzed and meanwhile located into the hotspots, in situ SERS monitoring of catalytic reactions can be achieved. The intense hotspots of localized electric fields of PPNs were evaluated by finite-difference time-domain simulation. By using PPNs as a substrate, SERS signals of molecules without Au surface-affinity groups were obtained, such as p-naphthoquinone and 4-nitrophenol. The PPNs showed high catalytic activities in the reduction of 4-nitrothiophenol to 4-aminothiophenol and 4-nitrophenol to 4-aminophenol, respectively. Besides, the SERS spectra of both 4-nitrophenol and 4-aminophenol during the reduction reaction of 4-nitrophenol with NaBH4 were first obtained, demonstrating their utilization in the detection of catalytic reactions.

Intelligent Platform for Simultaneous Detection of Multiple Aminoglycosides Based on a Ratiometric Paper-Based Device with Digital Fluorescence Detector Readout.

A digital fluorescence detector (DFD), a handheld fluorescence detection device, can convert the fluorescence signal of samples into the corresponding fluorescer concentration. Herein, by adopting a DFD as the readout, a novel intelligent platform was developed based on a ratiometric paper-based device (RPD) for multiple aminoglycoside detection. There are five layers and four parallel channels contained in the designed RPD, functioning as reagent storage, fluidic path control and signal processing, respectively. The rationale of this design lies in the fact that aptamer/graphitic carbon nitride nanosheet (Apt/g-C3N4 NS) modified layers can catalyze o-phenylenediamine to fluorescent 2,3-diaminophenazine (DAP) in the presence of H2O2. When Apt was removed from nanosheets via the Apt-target reaction, the peroxidase-like activity would be decreased, thus decreasing the production of DAP. All the changes of the fluorescence DAP signal can be read out using a portable DFD. Based on the DFD signal change related to the concentration of the target, a quantitative reaction platform was established. Furthermore, the sample flow and Apt-target reaction time can be reasonably regulated using the H2O2-cleavable hydrophobic compound modified layer placed between the target recognition region and detection region. Then, the practicality of this platform was verified through realizing sensitive analysis of streptomycin, tobramycin, and kanamycin simultaneously. Overall, with merits including portability and ease of operation, the platform shows great potential in on-site simultaneous detection of multiple targets, especially in resource-limited settings.

[Study on tissue culture system of Polygonatum cyrtonema].

In order to accelerate the breeding of the excellent seedlings of Polygonatum cyrtonema,tissue culture system of P. cyrtonema was established through the comprehensive regulation of key factors( leaf age,leaf location,basic media and plant growth regulators) and cytological basis of callus formation and differentiation was analyzed through paraffin section. The results showed that the 30-day-old leaf base explanton medium MS+6-BA 1. 50 mg·L~(-1)+2,4-D 0. 20 mg·L~(-1) had the highest induction rate( 80. 00%). The callus was initiated from cells on leaf base epidermis and near cortex,formed by the differentiation of middle vascular bundle cells. The optimal medium for adventitious bud differentiation was MS+ 6-BA 4. 00 mg·L~(-1)+ 2,4-D 0. 20 mg·L~(-1) with the differentiation rate of90. 33%,and the average number of buds was 5. 16. The adventitious buds had two origin types: exogenous and endogenous origin,formed by callus proximal cells and callus internal meristemoid. The adventitious bud proliferation medium was screened by orthogonal design,which determined the optimum combination was MS+ 6-BA 2. 00 mg·L~(-1)+NAA 0. 10 mg·L~(-1) and MS+ 6-BA 2. 00 mg·L~(-1)+NAA 0. 20 mg·L~(-1). The tubers with three leaves were cut and inoculated in the medium 1/2 MS+IBA 2. 00 mg·L~(-1),showing the highest rooting rate of 94. 00%. The rooting seedlings transplanted into the peat-vermiculite( 1 ∶ 1) matrix grew healthy and the survival rate was over 85. 00%. This research provided a novel solution for large-scale cultivation of P. cyrtonema seedling.

Separation of α-glucosidase inhibitors from Potentilla kleiniana Wight et Arn using solvent and flow-rate gradient high-speed counter-current chromatography target-guided by ultrafiltration HPLC-MS screening.

INTRODUCTION: Potentilla kleiniana Wight et Arn is widely used as a herbal medicine to treat type 2 diabetes. However, detailed information about its active compounds is lacking. OBJECTIVE: To develop an efficient method for the rapid screening and separation of α-glucosidase inhibitors from Potentilla kleiniana Wight et Arn. METHODOLOGY: Potential α-glucosidase inhibitors from Potentilla kleiniana Wight et Arn were rapidly screened out through ultrafiltration high-performance liquid chromatography mass spectrometry (HPLC-MS), and then followed by a target-guided high-speed counter-current chromatography (HSCCC) separation using two-phase solvent systems composed of n-hexane/ethyl acetate/methanol/water (1:10:1:10, v/v/v/v and 1:10:5:6, v/v/v/v), and adopting increasing flow-rate from 1.5 to 3.0 mL/min after 200 min. Their structures were identified by ultraviolet (UV), MS, proton nuclear magnetic resonance (1 H-NMR) and carbon-13 (13 C)-NMR, and their α-glucosidase inhibitory activities were assessed by in vitro assay. RESULTS: Five α-glucosidase inhibitors including gallic acid (25.7 mg, 98.2%, 1), brevifolincarboxylic acid (9.86 mg, 95.3%, 2), ethyl evifolincarboxylate (13.26 mg, 97.6%, 3), 3,3'-di-O-methylellagic acid-4'-O-ß-d-glucopyranoside (16.26 mg, 95.1%, 4), and 3,3'-di-O-methylellagic acid (10.54 mg, 96.8%, 5) were successfully purified from 250 mg n-butanol extract in a single run. Compounds 1, 2, 4 and 5 exhibited stronger α-glucosidase inhibitory activities[half maximal inhibition concentration (IC50 ) values at 173.41 ± 6.35, 323.46 ± 8.08, 44.63 ± 2.50, and 20.73 ± 2.56 µM, respectively] than acarbose (IC50 value at 332.12 ± 5.52 µM, reference compound). CONCLUSIONS: Notably, compounds 2-5 were reported in the Potentilla kleiniana Wight et Arn for the first time. The results indicated that the proposed method could be applied for the rapid screening and preparative separation of α-glucosidase inhibitors from a complex matrix.

[Cloning and function analysis of promoter of DcCDPK8 from Dendrobium catenatum].

DcCDPK8 involved in abiotic stress such as low temperature and signal transduction of hormones ABA and MeJA,but the transcriptional regulation is still unclear. In order to study the core promoter region of DcCDPK8 gene in Dendrobium catenatum and explore its transcriptional regulation mechanism,the DcCDPK8 gene promoter sequence was cloned by PCR from D. catenatum. Promoter sequence function was studied by fusion of 5 'terminal deletion and GUS gene. The results showed that the promoter sequence of DcCDPK8 gene has a low-temperature responsive element( LTR) between~(-1) 749 bp and-614 bp,two MeJA responsive elements between~(-1) 749 bp and-230 bp,and one ABA responsive elements between-614 bp and-230 bp. Three 5'-end different deletion fragments were constructed to fuse the eukaryotic expression vectors p BI121 with GUS,which were transformed into tobacco leaves. The GUS activity under cold stress treatment was DcCDPK8-p1>DcCDPK8-p2>DcCDPK8-p3. GUS activity under exogenous ABA induction was DcCDPK8-p1>DcCDPK8-p2>DcCDPK8-p3,and GUS activity under exogenous MeJA induction was DcCDPK8-p1>DcCDPK8-p2>DcCDPK8-p3. It is speculated that the ABA response element( ARE) in the promoter sequences of DcCDPK8 is positive regulatory role in response to exogenous ABA,the MeJA cis-acting element plays a negative role in response to exogenous MeJA.

Development of a "Dual Gates" Locked, Target-Triggered Nanodevice for Point-of-Care Testing with a Glucometer Readout.

Developing a facile and sensitive sensing platform is of importance for point-of-care testing (POCT). Herein, a sensitive and portable POCT platform based on "dual gates" aminated magnetic mesoporous silica nanocomposites (AMMS) bearing polydopamine (PDA)-aptamer (Apt) two-tier shells, as a novel nanodevice, is designed for target detection through a target-triggered glucose (GO) release from AMMS with personal glucometer (PGM) readout. In the absence of target, GO can be firmly captured in pores by the designed "dual gates", which would decrease the high background signal of this system and ensure the accuracy of the detection results. Upon the introduction of the target molecules under acidic conditions (pH 5.5), the subsequent PDA self-degradation and the specific Apt-target reaction can cause the departure of "dual gates" and the opening of pores to release the loaded GO molecules, which could be quantitatively monitored by a portable PGM. It has been demonstrated that such POCT platform shows high sensitivity and excellent selectivity for aflatoxin B1 (AFB1) detection, accompanied by the well-presented reproducibility and stability. Importantly, this sensing platform was further validated by assaying contaminated samples, where the obtained results were well matched with that by HPLC. Regarding the features of portability, high sensitivity, and high throughput detection, the developed platform might find wide applications in POCT.

In situ synthesis of gold nanoparticles on pseudo-paper films as flexible SERS substrate for sensitive detection of surface organic residues.

Surface enhanced Raman scattering (SERS) substrates that can be attached to rough, irregular surfaces and directly collect samples is especially useful for the detection of surface organic residues. Herein, novel AuNPs-pseudo-paper films (APPFs) with uniform structure, flexible properties and wicking capabilities were first fabricated and used as SERS substrate for the sensitive detection of surface pesticides residues. Gold nanoparticles (AuNPs) were in situ synthesized on pseudo-paper films (PPFs) by iterative seeding method to create lots of "hot-spots", accordingly exhibiting high SERS activity (SERS enhancement factor of 3.02 × 106). By virtue of polyethylenimine (PEI) grafted onto the dissolved microcrystalline cellulose (MCC), AuCl4- and AuNPs can firmly be bonded to the surfaces of PPFs. The prepared APPFs show high reproducibility (relative standard deviation of 6.13%), which is attributed to the uniform surface of the films. The fabricated APPFs SERS substrate allows rapid detection of surface pesticides residues by a facile "swabbing-measure" detection mode avoiding tedious and time-consuming sampling and separation processes. Based on their inherent SERS spectra, thiram, parathion methyl, and malachite green (MG) can be simultaneously detected on apple peel, which demonstrates the potential applicability of this developed protocol for surface organic residues analysis in agriculture and food security.

Rapid and visual detection of aflatoxin B1 in foodstuffs using aptamer/G-quadruplex DNAzyme probe with low background noise.

Contamination of foods by aflatoxin B1 (AFB1) is a common serious problem. To improve the efficiency of AFB1 detection, this study aims to develop a sensitive aptasensor for detection of AFB1 in food samples based on the catalytic effect of aptamer/G-quadruplex DNAzyme probe. The resulting reassembly of this probe in the presence of hemin and K+ catalyzes the generation of fluorescent 2,3-diaminophenazine (DAP) from o-phenylenediamine (OPD). Interestingly, we first found that the high background induced by the superfluous hemin can be effectively suppressed with the aid of sequential adsorption and magnetic separation by magnetic oxidized multiwall carbon nanotubes (Fe3O4@oMWCNTs). This aptasensor exhibits a high sensitivity toward AFB1 with a detection limit of 0.02 ng/mL. The assay also shows higher selectivity for AFB1 compared to other reported agents and can be employed to detect AFB1 in foodstuffs, which might find broad practical applications in other food contaminants determination.

Simultaneous In Situ Extraction and Fabrication of Surface-Enhanced Raman Scattering Substrate for Reliable Detection of Thiram Residue.

We report a novel strategy of simultaneous in situ extraction and fabrication of surface-enhanced Raman scattering substrate (IE-SERS) to perform selective and reliable on-site determination of thiram residue in soil, fruits, and vegetables. In this protocol, the thiram residue on complex surfaces can facilely diffuse into the solvent (dichloromethane (DCM)) and specifically bind to gold nanoparticles (AuNPs), affording the SERS substrate through the embedding of the thiram-trapped AuNPs into the cellulose p-toluenesulfonates (CTSAs) film through the evaporation of DCM. SERS signals of the specifically prepared CTSAs could be used as an internal standard to calibrate the absolute signal of thiram, which can avoid the fluctuation of SERS intensities caused by uneven and irregular morphology of SERS substrate. Thus, reliable quantitation of thiram through SERS detection and superior reproducibility in the SERS measurement (RSD = 4.21%) were achieved. As for directly sensing the thiram residue in soil, the established method shows strong anti-interference ability and a good linear response from 0.1 to 12 µg/g with a low limit of detection (LOD) of 50 ng/g, which is lower than that of all the previously reported methods. The recoveries range from 91.76 to 112.3% for thiram in paddy soils, indicating that the established IE-SERS method is reliable and applicable to the detection of thiram residue in real soil samples. In addition, the measurement of the residual thiram on strawberry and cucumber surface was also successfully accomplished by this strategy, indicating that the established method also has great potential in the in situ ultrasensitive detection of thiram on irregular fruits and vegetables.

4-Mercaptophenylboronic acid-modified spirally-curved mesoporous silica nanofibers coupled with ultra performance liquid chromatography-mass spectrometry for determination of brassinosteroids in plants.

Herein, for the first time, thiol-functionalized mesoporous silica (mSiO2-SH) nanofibers with a spirally-curved twisted hexagonal morphology were synthesized via a simple one-pot protocol. 4-Mercaptophenylboronic acids (4-MPBA) were attached onto the mSiO2-SH nanofibers via disulfide bond, serving as boronate affinity sorbent to selectively capture brassinosteroids (BRs) from plant extract. The resulting BRs-MPBA derivatives were easily eluted from the sorbent by cleaving the disulfide bond, which was subsequently subjected to ultra performance liquid chromatography-mass spectrometry (UPLC-MS) analysis. Thus, the in situ extraction/derivatization/desorption method coupled with UPLC-MS was established for the fast, sensitive and selective detection of BRs in plant tissues. Finally, based on the developed method, endogenous BRs were successfully detected in leaf of H. lupulus L., silique of A. thaliana, and panicle of O. sativa L.

[Effects of germplasm and host tree trunk on endophytic fungal communities in epiphytic Dendrobium catenatum].

In order to investigate the effects of germplasm and host tree trunk on endophytic fungal communities in epiphytic Dendrobium catenatum, a total of 3 835 isolates were recovered from roots, stems and leaves of four D. catenatum germplasms attached to one kind of host tree trunk and one germplasm attached to four kinds of epiphyte-host tree trunks. A total of 152 taxa were identified and classified based on the fungal cultural characteristics and phylogenetic analyses of ITS sequences. The taxa were assigned to 60 genera, 35 families, 21 orders and 5 classes of 2 phyla. The results indicated that D. catenatum cultivated in stereo cultivation harbor variety of fungi. The dominant fungal groups were different between Lin'an and Yiwu. Moreover, several groups showed geographical specificity, such as Arthrinium, Coniochaeta, Fusarium, Neofusicoccum and Zopfiella only dominating in Panshan of Lin'an, while Alternaria, Bjerkandera, Cercophora, Nigrospora and Trichoderma only dominating in Shangxi of Yiwu. There was no significant difference in diversity or species richness of endophytic fungi neither among germplasm nor host tree trunk. However, the richness and diversity indices exhibited a strong dependence on tissue type (P<0.05). The germplasm and host tree trunk impact the distribution patterns of endophytic fungi less than tissue type. Nevertheless, the relative frequencies of the dominant fungal groups were different among germplasms or host tree trunk types. Furthermore, there were some fungal species specific to certain germplasm or host tree trunk. This might be due to the distinctions in growth traits and chemical compositions of D. catenatum owning to the differences in D. catenatumgenetic background and microenvironment of host tree. Most of fungal taxa exhibit tissue specificity or preference. These results provide the basis for the study on the relationship between endophytic fungi and D. catenatum in stereo cultivation mode.

[Effects of sampling time on polysaccharides of Dendrobium catenatum under temperature-controlled condition].

In order to reveal the accumulation trend of polysaccharides in Dendrobium catenatum and determine the effect of sampling time on polysaccharides, D. Catenatum D21 clone was harvested from January to December after culturing for 2 to 5 months in the growth chamber with constant temperature. Polysaccharides were determined by phenol-sulfuric acid method and the monosaccharide compositions were analyzed by pre-column derivative-UPLC. The results showed that the content of polysaccharide and its key component mannose was positively correlated with the culture time, but the contents of polysaccharides in all kinds of culture peaked from 5 to 6 months, which were consistent with the trend of field planting. The results suggested that the trend of polysaccharide accumulation in the plant could be related to the life rhythm of the sensory seasons of D. catenatum, which was significantly affected by the harvesting season, even under the constant condition of the culture chamber.

Synthesis of Multi-Au-Nanoparticle-Embedded Mesoporous Silica Microspheres as Self-Filtering and Reusable Substrates for SERS Detection.

Surface-enhanced Raman-scattering-based (SERS-based) biosensing in biological fluids is constrained by nonspecific macromolecule adsorptions and disposable property of the SERS substrate. Here, novel multi-Au-nanoparticle-embedded mesoporous silica microspheres (AuNPs/mSiO2) were prepared using a one-pot method, which served as reliable substrates for SERS enhancement associated with salient features of self-filtering ability and reusability. The fabrication and physical characterization of AuNPs/mSiO2 microspheres were discussed, and SERS activity of this novel substrate was investigated by using 4-mercaptobenzoic acid (4-MBA) as Raman probe. The responses of our substrates to Raman intensities exhibited a SERS enhancement factor of 2.01 × 107 and high reproducibility (relative standard deviation of 6.13%). Proof-of-concept experiments were designed to evaluate the self-filtering ability of the substrates in bovine serum albumin (BSA) and human serum solution, separately. The results clearly demonstrate that mesoporous SiO2 can serve as a molecular sieve via size exclusion and avoid Raman signal interference of biomacromolecules in biological fluids. Subsequently, feasibility of practical application of AuNPs/mSiO2 microspheres was assessed by quantitative detection of methotrexate (MTA) in serum. The method exhibited good linearity between 1 and 110 nM with the correlation coefficients of 0.996, which proved that the obtained AuNPs/mSiO2 microspheres were good SERS substrates for determination of small biomolecules directly in biological fluids without need of manipulating samples. In addition, the substrate maintained its SERS response during multiple cycles, which was evaluated by recording Raman signals for 4-MBA before and after thermal annealing, thereby demonstrating the high thermostability and satisfactory reusability. These results offered the AuNPs/mSiO2 microspheres attractive advantages in their SERS biosensing.

[Effects of cultivation environments on Dendrobium catenatum].

The study was aimed to clarify the effect of three cultivation environments on the growth and metabolism of Dendrobium catenatum C13 group. There were three different cultivation conditions including rock epiphytic cultivation, pear epiphytic cultivation and pot cultivation. Morphological characteristics and agronomic characters of D. catenatum were observed and measured. Microstructure, contents of polysaccharide and alcohol-soluble extracts were measured by paraffin section method, phenol-sulfuric acid method and hot-dip method, respectively. The result showed that the cultivation environment significantly affected the growth of D. catenatum, the leaves of D. catenatum that cultivated on the rock and pear were sparse and small, the stems were short and purple and the root system was developed. Compare with potted cultivation, D. catenatum from rock epiphytic cultivation and pear epiphytic cultivation showed the following characteristics in the microstructure: the upper epidermis became thicker, the epidermal hair in the epidermis became denser, stomatal showed smaller and denser, the cell wall of exodermis, endoderm and medulla became thicker, the cell of velamen, exodermis, endoderm and medulla were smaller and arranged more closely, but the cultivation environment did not produce specific tissue structure, mainly changed in the structural parameters of size and quantity. The growth environments also influenced contents of polysaccharides and alcohol-soluble extracts. The dontents of polysaccharides and alcohol-soluble extracts in D. catenatum from rock epiphytic were the highest, reached 37.34% and 11.66%, the second was pear epiphytic, both higher than pot cultivation, alcohol-soluble extracts contents in D. catenatum from rock epiphytic are more complex, which shows that rock epiphytic is conducive to the accumulation of secondary metabolites in D. catenatum.

[Dendrobium officinale cliff epiphytic cultivation method].

To solve the issues of costly planting of facility cultivation method and inferior efficacy than wild herbs of Dendrobium officinale, the cliff epiphytic cultivation method was studied. To research the growth, agronomic traits, yield, polysaccharide and alcohol-soluble extract contents were measured on the D. officinale from different water regulation and cliff slope gradients treatments. The results showed that D. officinale epiphytic at 85 degrees-90 degrees cliff and sprayed water 1-2 h x d(-1) at the growing season can get better growth and obtain high yield, and the morphology has no different from wild cliff D. officinale, even in the environments without shade. The contents of polysaccharide and alcohol-soluble extract are closely related to the physiological ages, but significantly higher than the facility cultivation. It is possible that environmental stresses benefit the accumulation of polysaccharides, alcohol-soluble extract and other efficient ingredients.