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PubMed1989

[In vitro culture of premature seeds of Dendrobium huoshanense Tang et Cheng].

The premature seeds of D. huoshanense collected in September or October can develop normally in MS or Kundson media with BAI and NAA 0.5 mg/L and form complete plantlets. The premature seeds cultured in dark for 22 days and then in low light intensity give the highest germination percent age(91%). The suitable temperature for the germination of D. huoshanense premature seeds is 25-27 degrees C.

Culture Techniques↗
PubMed2001

[rDNA its sequencing of Herba Dendrobii (Huangcao)].

AIM: To study the genetic diversity of ITS sequences of Herba Dendrobii (Huangcao) and analyze the utility of ITS sequences in molecular authentication of Herba Dendrobii (Huangcao) and phylogenetic of Dendrobium. METHODS: The ITS gene fragment was amplified using a pair of primers. The PCR products were purified and sequenced by the methods of Sanger Dideoxy. RESULTS: The DNA sequence of 228-233 bp ITS 1, 242-247 bp ITS 2 gene fragments and 5.8S rDNA were obtained from 14 samples of Dendrobium. The interspecific substitution varies from 11.79% to 31.58% at ITS 1 and 10.29% to 25.30% at ITS 2. The intraspecific substitution of D. nobile is 0.87% at ITS 1 and without difference at ITS 2. The substitution between Dendrobium and outgroup varies from 23.56% to 36.89% at ITS 1 and 26.52% to 33.31% at ITS 2. The phylogenetic tree based on ITS 1 and ITS 2 data was set up. CONCLUSION: The ITS 1 and ITS 2 gene fragments were highly conservative at intraspecific level in Dendrebium, while they were less conservative at interspecific level in D. nobile. They were least conservative between Dendrobium and outgroup. Hence, the sequence of this fragment is a good molecular marker for authentication of the Huangcao. But, further study is necessary for the phylogenetic of Dendrobium.

Base Sequence↗
PubMed1998

Synergism in replication of cymbidium mosaic potexvirus (CymMV) and odontoglossum ringspot tobamovirus (ORSV) RNA in orchid protoplasts.

An in vitro orchid protoplast isolation method to study replication kinetics of CymMV and ORSV was developed. This method allows the isolation of viable and raphid-free petal protoplasts from an orchid hybrid, Dendrobium Sonia (Dendrobium Caesar x Dendrobium Tomie Drake). The optimum field strength for both viral RNA to achieve good efficiency of electroporation was 750 V/cm and the optimum viral RNA concentration required was 1 microgram and 4 micrograms per 2 x 10(6) protoplasts for CymMV and ORSV, respectively. Autoradiographs of Northern blots depicting the viral genomic and subgenomic RNA in the extracts, referred to as the "Replication Footprint Profiles" (RFP) of specific CymMV/ORSV virus were prepared at different time intervals. Viral RNA synthesis reached a maximum at 18 h for CymMV and 24 h for ORSV. When CymMV and ORSV viral RNA were electroporated into the protoplasts simultaneously, detection signals of both the positive and negative strand viral RNA increased as compared to the singly infected protoplasts. Thus, synergism in replication of CymMV and ORSV was observed in orchid protoplasts.

Electroporation↗
PubMed1989

[Microscopical examination of leaf sheathes of the Chinese drug "Shihu", herba dendrobii].

"Shihu", a famous Chinese traditional drug, is used to replenish the vital essence of the lung and stomach, to clear up the excessive heat and to promote the secretion of the body fluid. The commercial crude drugs under the general name "Shihu" are mostly derived from a number of species of the genus Dendrobium. It is difficult to identify exactly the botanical origin of these crude drugs through macroscopical examination. In order to tackle this problem, the leaf sheathes of the stems of 16 species of the genus Dendrobium are examined microscopically and the characteristics of their epidermal cells and calcium oxalate crystals are compared. The diagnostic features found are proved to be useful for the identification of the botanical origin of commercial samples of the "Shihu". In this paper the microscopical characters of 16 Dendrobium species are described with illustration.

Calcium Oxalate↗
PubMed2006

A simple and convenient approach for isolating RNA from highly viscous plant tissue rich in polysaccharides.

RNA isolation is a prerequisite to the study of gene expression of herbaceous plant Dendrobium nobile under an environmental stress. However, RNA isolation is difficult in the plant of genus Dendrobium, which is relatively viscous, due to being rich in polysaccharides. The common protocols for RNA isolation are tedious and usually result in poor yields when applied to D. nobile. Here, we describe a simple and convenient method for high quality total RNA extraction from D. nobile. Main procedures are as follows: smashing plant tissue and cell wall by means of pre-cooled citrate homogenization, cleaving cell membrane by using guanidine hydrochloride lysis buffer, removing proteins, polyphenols and polysaccharides by acidic phenol/chloroform. It is particularly useful for processing large numbers of plant samples. The whole process can be completed within 2.5 h. The extracted RNA is suitable for applications such as RT-PCR, Northern analysis and screening of differential expression genes.

Cell Culture Techniques↗
PubMedDate not supplied

[Localization of associative cyanobacteria on the roots of epiphytic orchids].

This work is the first study of the localization of phototrophic microorganisms in the rhizoplane and velamen of epiphytic orchids, namely on the aerial and substrate roots of Acampe papillosa and Dendrobium moschatum and on the aerial roots of the Phalaenopsis amabilis and Dendrobium phalaenopsis. The composition of the bacterial community on the plant roots depended on the conditions of plant growth. Under conditions simulating climate of moist tropical forests, the aerial roots proved to be populated with phototrophic microorganisms among which cyanobacteria predominated. Interlaced fungal hyphae and filamentous cyanobacteria formed a sheath on the surface of aerial roots. The nitrogen-fixing capacity of the sheath of aerial roots was studied by the example of P. amabilis.

Cyanobacteria↗
PubMedDate not supplied

[Associative cyanobacteria isolated from the roots of epiphytic orchids].

Associative cyanobacteria were isolated from the rhizoplane and velamen of the aerial roots of the epiphytic orchids Acampe papillosa, Phalaenopsis amabilis, and Dendrobium moschatum and from the substrate roots of Acampe papillosa and Dendrobium moschatum. Cyanobacteria were isolated on complete and nitrogen-free variants of BG-11 medium. On all media and in all samples, cyanobacteria of the genus Nostoc predominated. Nostoc, Anabaena, and Calothrix were isolated from the surface of the A. papillosa aerial roots, whereas the isolates from the substrate roots were Nostoc, Oscillatoria, and representatives of the LPP-group (Lyngbia, Phormidium, and Plectonema, incapable of nitrogen fixation). On the D. moschatum substrate roots, Nostoc and LPP-group representatives were also found, as well as Fischerella. On the aerial roots of P. amabilis and D. phalaenopsis grown in a greenhouse simulating the climate of moist tropical forest, cyanobacteria were represented by Nostoc, LPP-group, and Scytonema in the D. phalaenopsis and by Nostoc, Scytonema, Calothrix, Spirulina, Oscillatoria, and the LPP-group in P. amabilis. For D. moschatum, the spectra of cyanobacteria populating the substrate root zhizophane and the substrate (pine bark) were compared. In the parenchyma of the aerial roots of P. amabilis, fungal hyphae and/or their half-degraded remains were detected, which testifies to the presence of mycorrhizal fungi this plant. This phenomenon is attributed to the presence of a sheath formed by cyanobacteria and serving as a substrate for fungi.

Cyanobacteria↗
PubMedDate not supplied

Molecular evolution and functional specialization of chalcone synthase superfamily from Phalaenopsis orchid.

Plant genomes appear to exploit the process of gene duplication as a primary means of acquiring biochemical and developmental flexibility. The best example is the gene encoding chalcone synthase (CHS, EC2.3.1.74), the first committed step in flavonoid biosynthesis. In this study, we examined the molecular evolution of three CHS family members of Phalaenopsis including a novel chs gene (phchs5), which is slowly evolved. The inferred phylogeny of the chs genes of Phalaenopsis with other two orchid plants, Bromoheadia finlaysoniana and Dendrobium hybrid, suggested that gene duplication and divergence have occurred before divergence of these three genera. Relatively quantitative RT-PCR analysis identified expression patterns of these three chs genes in different floral tissues at different developmental stages. Phchs5 was the most abundantly expressed chs gene in floral organs and it was specifically transcribed in petal and lip at the stages when anthocyanin accumulated (stage1-4). Phchs3 and phchs4 were expressed at much lower levels than phchs5. Phchs3 was expressed in pigmented tissue (including lip, petal and sepal) at middle stages (stages 2-4) and in colorless reproductive tissue at late stage (stage 5). Phchs4 was only expressed in petal at earlier stages (stage 1-3) and in lip at middle stage (stage 4). These results present new data on differentiation of gene expression among duplicate copies of chs genes in Phalaenopsis.

Acyltransferases↗
PubMed2006

An electrochemical approach to monitor pH change in agar media during plant tissue culture.

In this work, metal oxide microelectrodes were developed to monitor pH change in agar media during plant tissue culture. An antimony wire was produced by a new approach "capillary melt method". The surface of the obtained antimony wire was oxidized in a potassium nitrate melt to fabricate an antimony oxide film for pH sensing. Characterization results show that the oxide layer grown on the wire surface consists of Sb(2)O(3) crystal phase. The sensing response, open-circuit potential, of the electrode has a good linear relationship (R(2)=1.00) with pH value of the test solution. Adding organic compounds into the test media would not affect the linear relationship, although the slope of the lines varied with different ingredients added. The antimony oxide electrodes were employed to continuously monitor pH change of agar culture media during a 2-week plant tissue culture of Dendrobium candidum. The antimony oxide electrode fabricated this way has the advantages of low cost, easy fabrication, fast response, and almost no contamination introduced into the system. It would be suitable for in situ and continuous pH measurement in many bio applications.

Agar↗