Dendrobium Research Articles

Effects of Dendrobium candidum Polysaccharide on Immunity,Intestinal Microbiota and Enzyme Activity in Mice with Spleen Deficiency Constipation

Effects of Dendrobium candidum Polysaccharide on Immunity,Intestinal Microbiota and Enzyme Activity in Mice with Spleen Deficiency Constipation

Respon Pertumbuhan Anggrek Dendrobium Terhadap Jenis Media Tanam dan Pupuk Daun

The use of ferns as orchid growing media feel expensive, so it is necessary to find an alternative media as a media surrogate fern that has been used. This study aimed to explore alternative growing media and fertilizer is good for growth and development of dendrobium orchids. Selection of a good planting medium and the proper use of fertilizers can be expected to support healthy plant growth and quality of orchids. experiments were conducted at Greenhouse Faculty of Agriculture Lampung University. The experiment was conducted using a randomized design perfectly with the treatment group factorial (6x2). The first factor is the type of growing medium consists of wood charcoal (M1), fern (M2), husk + sawdust (M3), acacia bark (M4), cocochip (M5) and coconut bark (M6). The second factor is the type of foliar fertilizer consists of Gandasil (P1) and Hyponex (P2). Data were analyzed by analysis of variance followed by HSD test at 5% level. The results showed that the use of media orchids ferns produce good vegetative growth, no different to use of planting medium charcoal, charcoal husk + sawdust, bark and bark acacia tree coconut, but it is different than the use of cocochip shown in variable plant height, number of leaves , leaf length and leaf width. While fertilizers orchid leaves that produce good growth is fertilizer of Gandasil

Respon Pertumbuhan Anggrek Dendrobium Terhadap Jenis Media Tanam Dan Pupuk Daun

The use of ferns as growing media orchids ranging deemed expensive , so it is necessary to find an alternative media as a media surrogate fern that has been used .This study aimed to explore alternative growing media and fertilizers are good for growth and development of dendrobium orchids . Selection of a good planting medium and the proper use of fertilizers can be expected to support healthy plant growth and quality of orchids .Greenhouse experiments were conducted at the Faculty of Agriculture University of Lampung . Treatment arrangement was factorial by randomized complete block design with three replication. The treatment is done byp factorial ( 6x2 ) . The first factor is the type of growing medium consists of wood charcoal ( M1 ) , ferns ( M2 ) , husk + sawdust ( M3 ) , acacia bark ( M4 ) , cocochip ( M5 ) and coconut bark ( M6 ) . The second factor is the type of foliar fertilizer consists of Gandasil ( P1 ) and Hyponex ( P2 ) . Data were analyzed by analysis of variance followed by HSD test at 5% level .The results showed that the use of media orchids ferns produce good vegetative growth , not unlike the use of planting medium charcoal , charcoal husk + sawdust , bark and bark acacia tree oil , but it is different than the use of cocochip shown in variable plant height , number of leaves , leaf length and leaf width . While foliar fertilizers that produce good growth is fertilizer Gandasil . Key word: dendrobium , growing media , foliar fertilizers

Pengaruh Jenis Pupuk dan Konsentrasi Benzyladenin (BA) Terhadap Pertumbuhan dan Pembungaan Anggrek Dendrobium Hibrida

Dendrobium as ornamental plants that are used as cut flowers, potted plants, wreaths, garden ornament has a high economic value (due to the type, beauty, shape, texture, flower size, and rarity), has a broad market opportunities, sources of germplasm as mains to cross in order to get new varieties, and to cultivate them do not require large tracts of land. to get orchid production which is reached with good cultivation, one of them is by using fertilizers and growth regulators (PGR) to obtain growth and good flowering of orchids. This study was conducted to answer the following questions: (1) Which type of foliar fertilizer that can generate the best response to the growth and flowering of orchid Dendrobium, (2) how the effect of benzyladenine (BA) on the growth and flowering of orchid Dendrobium, (3) whether there is an interaction between foliar fertilizers and provision of benzyladenine (BA) to influence the growth and flowering of orchid Dendrobium. The research conducted in the greenhouse, Faculty of Agriculture, University of Lampung from January to June 2014. The experiments were carried out with a complete randomized block design with three replications. The treatments arranged in factorial (2x5). The first factor of 2 types of fertilizers, was (NPK 20-15-15) and (NPK 10-40-15). The second factor is the various concentrations of BA are: 0, 100, 200, 300, and 400 mg/l. based on data and discussion of experimental results that have been raised, it can be concluded as follows: Gandasil fertilizer (NPK 20-15-15) and Hyponex (NPK 10-40-15), had no effect on the growth and flowering of plants Dendrobium hybrids indicated by a variable percentage of plants to germinate, the number of new shoots, the height of new shoots, the increase of leaf pseudo stem diameter, and the percentage of flowering plants. Application of benzyladenine (BA) on the concentration of 100-400 mg / l, can stimulate flowering orchid hybrid Dendrobium, which is indicated by an increase in the percentage of flowering from 60.50 to 64.83%. Application of BA on the concentration of 100-400 mg / l had no effect on the percentage of ornamental plants whis have new sprout, and the number and the height of new shoots. There is no interaction between the two types of NPK (20-15-15 and 10-40-15), with concentrations of BA in influencing all observed variables. Keywords: Dendrobium, Two kinds of completed fertelizers, Benzyladenine, flowering

Culturable fungal endophytes in shoots of Dendrobium aqueum Lindley – An imperiled orchid

Three non–mycorrhizal endophytic fungi were isolated and identified in a threatened epiphytic orchid Dendrobium aqueum Lindley. Stem, leaf and pseudobulb segments obtained from wild plants collected from Kolli hills, Tamil Nadu, India were used to isolate the fungi. Both morphology and molecular sequencing of internal transcribed spacer (ITS) regions of endophytic fungi revealed that all three isolates belonged to the genus Colletotrichum. Endophytes colonization rate was higher on basal stem segments (27.78%) compared to other stem portions, leaves (16.67%) and pseudobulbs (16.67%). All three endophytes showed organ specificity with higher assemblage in stem segments, whereas leaf and pseudobulb segments contained only one endophyte. The wild plants showed no major disease symptoms to affect leaf or plant growth, except few minor dark or grey spots on the mature senescing leaves. Hence, the Colletotrichum isolates were found to be the dominant endophytes of D. aqueum, perceived to have a symbiotic relationship with it, as there were no other fungal isolates found in this study.

Stems age, nitrogen fertilizer and salicylic acid application in cutting induction of noble dendrobium orchid of the Yamamoto series cultivars

Propagation of noble dendrobium orchid (Dendrobium nobile Lindl.) by cutting was studied in two experiments. In the first experiment we evaluated the effect stem age on propagation success: mature stems - from already bloomed stems; and young stems – yet to bloom; and Nitrogen fertilizer application, from two sources: as Nitrate and Ammonium (respectively as Calcium Nitrate at concentrations of: 5.81 gL-1; 11.61 gL-1; 17.42 gL-1; and Urea at concentrations of 2.00 gL-1; 4.00 gL-1 and 6.00 gL-1 plus control treatments). We evaluated the following parameters: the number of cuttings stalks that launched shoots and/or roots, vigor, number of roots per plant and root length per plant. Factorial analysis of variance (stems age x source of Nitrogen; and age of stem x Nitrogen level) was applied using a Generalized Linear Model (GLM) approach. Where significant differences were observed, averages were compared using post-hoc tests (Tukey). Propagation success was higher using cuttings from mature stems (60.2%), a value 1.6 times higher than obtained with stem cuttings from young stems (38.0%). Application of Nitrogen, in both forms, did not influence any of the evaluated parameters. In the second experiment we treated cuttings from mature stems with Salicylic acid in 3 concentrations (0.10 mM; 0.50 mM; 1.00 mM and plus a control treatment). Evaluated parameters included proportion of cuttings stalks that launched shoots and/or roots, leaf length, root length, and number of roots per stem cutting. Factorial analysis of variance was applied with post-hoc tests. Application of 0.50 mM of Salicylic acid increased the proportion of cuttings stalks that launched shoots and/or roots by 20.5% relative to the control treatment.

Effect of germination media on in vitro symbiotic seed germination of three Dendrobium orchids

In vitro symbiotic seed germination has become increasingly popular for orchid propagation. With very few exceptions, in vitro symbiotic seed germination methods use oat meal agar (OMA) as the medium. However, effects of oat concentrations on symbiotic germination of orchid seeds have not been investigated. In our first experiment, effectiveness of three concentrations of ground oat (1, 5, or 10g/l) in OMA inoculated with an orchid mycorrhizal fungus (Tulasnella deliquescens (Juel) Juel), uninoculated OMA (10g/l of oat) and one fifth Murashige and Skoog medium containing 6g/l of sucrose (1/5MS) on promoting seed germination of Dendrobium lindleyi Steud. were compared. Germination and protocorm development of D. lindleyi were found to be enhanced by higher oat concentrations. The OMA containing 10g/l of oat with mycorrhizal inoculation also outperformed 1/5MS. In our second and third experiments, the use of common orchid cultivation substrates as alternative media for in vitro symbiotic orchid seed germination was investigated. For Dendrobium fimbriatum Hook., we demonstrated that sphagnum peat moss inoculated with T. deliquescens either isolate Da-KP-0-1 or Pv-PC-1-1 in plastic containers could be used to germinate the orchid to advanced seedling stage, although the germination percentages were low, probably due to the waterlogged characteristic of the peat moss and low ventilation of the plastic boxes. For Dendrobium findlayanum C.S.P. Parish & Rchb.f., we used the mixture of peat moss and coir dust packed in Petri dishes to solve the mentioned problems and compared the effectiveness of this system to OMA and 1/5MS. The three treatments resulted in similar germination percentages but the symbiotic methods were more effective than 1/5MS in promoting protocorm development of D. findlayanum. The findings of this study can be used to improve symbiotic germination media and they encourage the use of symbiotic germination method as mean for orchid seed propagation.

Comparative analysis of Dendrobium plastomes and utility of plastomic mutational hotspots

Dendrobium is one of the largest genera in Orchidaceae, comprising about 800–1500 species mainly distributed in tropical Asia, Australasia, and Australia. There are 74 species and two varieties of this genus in China. Because of their ornamental and commercial value, Dendrobium orchids have been studied at low taxonomic levels. However, structural changes and effective mutational hotspots of Dendrobium plastomes have rarely been documented. Here, 30 Dendrobium plastomes were compared, comprising 25 newly sequenced in this study and five previously published. Except for their differences in NDH genes, these plastomes shared identical gene content and order. Comparative analyses revealed that the variation in size of Dendroubium plastomes was associated with dramatically changed length of InDels. Furthermore, ten loci were identified as the top-ten mutational hotspots, whose sequence variability was almost unchanged with more than 10 plastomes sampled, suggesting that they may be powerful markers for Dendrobium species. In addition, primer pairs of 47 polymorphic microsatellites were developed. After assessing the mean BS values of all combinations derived from the top-ten hotspots, we recommend that the combination of five hotspots—trnT-trnL, rpl32-trnL, clpP-psbB, trnL intron, and rps16-trnQ—should be used in the phylogenetic and identification studies of Dendrobium.

ITRAQ and RNA-Seq Analyses Provide New Insights into Regulation Mechanism of Symbiotic Germination of Dendrobium officinale Seeds (Orchidaceae).

Mycorrhizal fungi colonize orchid seeds and induce germination. This so-called symbiotic germination is a critical developmental process in the lifecycle of all orchid species. However, the molecular changes that occur during orchid seed symbiotic germination remain largely unknown. To better understand the molecular mechanism of orchid seed germination, we performed a comparative transcriptomic and proteomic analysis of the Chinese traditional medicinal orchid Dendrobium officinale to explore the change in protein expression at the different developmental stages during asymbiotic and symbiotic germination and identify the key proteins that regulate the symbiotic germination of orchid seeds. Among 2256 identified plant proteins, 308 were differentially expressed across three developmental stages during asymbiotic and symbiotic germination, and 229 were differentially expressed during symbiotic germination compared to asymbiotic development. Of these, 32 proteins were coup-regulated at both the proteomic and transcriptomic levels during symbiotic germination compared to asymbiotic germination. Our results suggest that symbiotic germination of D. officinale seeds shares a common signaling pathway with asymbiotic germination during the early germination stage. However, compared to asymbiotic germination, fungal colonization of orchid seeds appears to induce higher and earlier expression of some key proteins involved in lipid and carbohydrate metabolism and thus improves the efficiency of utilization of stored substances present in the embryo. This study provides new insight into the molecular basis of orchid seed germination.

Economic Returns and Enhanced Quality in Orchid (Dendrobium Sonia 17) Using Biosafe Compound- Chitosan

Economic Returns and Enhanced Quality in Orchid (Dendrobium Sonia 17) Using Biosafe Compound- Chitosan

Pollen ultrastructure of genus Dendrobium orchids as a learning resource

Anggrek genus Dendrobium merupakan salah satu genus dari divisi spermatophyta yang merupakan kelompok tumbuhan yang berkembang dengan menggunakan biji. Tumbuhan berbiji tentu memiliki bunga sebagai alat perkembangan generatifnya. Perkembangan generatif pada bunga artinya pertemuan antara sel gamet jantan dan sel gamet betina. Sel gamet betina pada tumbuhan dihasilkan oleh putik, sedangkan sel gamet jantan disebut serbuk sari atau pollen. Genus Dendrobium merupakan salah satu kekayaan alam Indonesia, jumlahnya diperkirakan mencapai 275 spesies. Penelitian ini bertujuan untuk mengetahui bagaimana ultrastruktur pollen anggrek genus Dendrobium dari sepuluh spesies yang diamati menggunakan SEM. Jenis penelitian ini adalah deskriptif kualitatif. Hasil penelitian menunjukkan unit pollen untuk semua spesies yaitu kategori pollinia, sedangkan untuk polaritas pollen adalah apolar. Jenis aperture kesepuluh spesies yang diamati mempunyai aperture dengan pola yang tidak beraturan dan lebih dari enam yang disebut colpate. Bentuk pollen dari semua spesies yang diteliti bentuknya adalah subprolate hingga prolate dan ukuran pollen termasuk dalam kategori minuta hingga media. Ornamentasi pollen atau skluptur pollen tidak teridentifikasi dikarenakan ukuran pollen yang terlalu kecil, permukaan pollen terlihat kurang jelas. Sumber belajar yang digunakan adalah atlas.

Anthocyanin biosynthesis regulation of DhMYB2 and DhbHLH1 in Dendrobium hybrids petals

Dendrobium hybrids orchid are popular throughout the world. They have various floral color and pigmentation patterns that are mainly caused by anthocyanins. It is well established that anthocyanin biosynthesis is regulated by the interplay between MYB and bHLH transcription factors (TF) in most plants. In this study, we identified one R2R3-MYB gene, DhMYB2, and one bHLH gene, DhbHLH1, from a Dendrobium hybrid. Their expression profiles were related to anthocyanin pigmentation in Dendrobium petals. Transient over-expression of these two TF genes showed that both DhMYB2 and DhbHLH1 resulted in anthocyanin production in white petals. The interaction between the two TFs was observed in vitro. In different Dendrobium hybrids petals with various pigmentations, DhMYB2 and DhbHLH1 were co-expressed with DhDFR and DhANS, which are regarded as potential regulatory targets of the two TFs. In flowers with distinct purple lips but white or yellow petals/sepals, the expression of DhbHLH1 was only related to anthocyanin accumulation in the lips. Taken together, DhMYB2 interacted with DhbHLH1 to regulate anthocyanin production in Dendrobium hybrid petals. DhbHLH1 was also responsible for the distinct anthocyanin pigmentation in lip tissues. The functional characterization of DhMYB2 and DhbHLH1 will improve understanding of anthocyanin biosynthesis modulation in Dendrobium orchids.

Agrobacterium-mediated transformation of Dendrobium orchid with the flavanone 3-hydroxylase gene

The Ascocenda flavanone 3-hydroxylase (AcF3H) gene was successfully transformed into Dendrobium 5N white orchid plants using Agrobacterium-mediated gene transformation. In this study, for the first time, we report the construction of a plant expression vector harboring the AcF3H gene using the Gateway cloning system. Protocorm-like bodies (PLBs) were cocultivated with the Agrobacterium tumefaciens strain AGL1 harboring the plant expression vector pGWB5-AcF3H, which contained the hygromycin phosphotransferase (hpt) gene as a selectable marker. The highest transformation efficiency (10.13%) was achieved when PLBs were cocultivated with Agrobacterium cells for 15 min. Three months after the transformation, the plantlets were regenerated, and the transgenic plants were confirmed by polymerase chain reaction (PCR) analysis using specific primers for the hpt gene and 35S promoter region. PCR products of approximately 400 and 500 bp, corresponding to the hpt gene and the 35S promoter, respectively, were detected in the transgenic plants, while no such product was observed in nontransgenic plants, indicating that the AcF3H gene was integrated into the genome of Dendrobium 5N white orchid plants. The transient expression of the AcF3H gene in Dendrobium 5N white and Dendrobium Anna petals was performed using the agroinfiltration technique, and the results demonstrated that no cyanidin content was detected in the Dendrobium 5N white petals after AcF3H infiltration. In contrast, the cyanidin content was increased by approximately 6% in the Dendrobium Anna petals, suggesting that the AcF3H gene was transiently expressed in this orchid.

Phylogeography of the endangered orchid Dendrobium moniliforme in East Asia inferred from chloroplast DNA sequences

The aim of the current study was to elucidate the phylogeographic history of Dendrobium moniliforme, an endangered orchid species, based on two chloroplast DNA (cpDNA) markers (trnC-petN and trnE-trnT). One hundred and thirty-five samples were collected from 18 natural populations of D. moniliforme covering the entire range of the Sino-Japanese Floristic Region (SJFR) of East Asia. A total of 35 distinct cpDNA haplotypes were identified in these populations, of which 23 haplotypes were each present in only one sample and thus restricted to a single population. The significantly larger NST value (0.586) than GST (0.328) (p < 0.05) demonstrated the presence of strong phylogeographic structure. Phylogenetic analyses indicated that all haplotypes were clustered into two lineages. The genetic diversity of D. moniliforme was high at the species level, reflected in its haplotype diversity (Hd=0.8862), nucleotide diversity (Pi=0.00361), total genetic diversity (HT=0.9011), and significant differentiation (ΦST=0.5482). Based on mismatch distribution analysis and neutrality tests, population expansion was evident in all sampled populations and also in all populations sampled in mainland China. Three refuge areas were identified, one each in southwestern China, central-southeastern China, and the CKJ (Taiwan, Japan and Korea) Islands. The results supported the hypothesis that glacial refugia were maintained on different spatial-temporal scales in the SJFR during the last glacial maximum or earlier cold periods, suggesting that Quaternary refugial isolation promoted allopatric speciation of D. moniliforme in East Asia.

A novel approach for the selection of Cattleya hybrids for precocious and season-independent flowering

Orchids are one of the most commercialized potted flowers in the world. Cattleya hybrids are highly valued by the international flower market but its horticultural characteristics can still benefit from genetic improvement, particularly the production of precocious cultivars and season-independent flowering. This improvement would allow Cattleya to compete with Phalaenopsis and Dendrobium orchids, as well as with other potted and cut-flower groups. The aim of this work was first to obtain interspecific hybrids between two superior cultivars, Cattleya ‘Pao de Acucar’ and Brassolaeliocattley ‘Sun King’. This was followed by selection among the progeny for precocious flowering and other valuable horticultural and ornamental characteristics. Seedlings grown in vitro were initially selected based on shoot and root development over a period of 6 months, then acclimatized in a greenhouse. From a total of 200 acclimatized plantlets, five (i.e., 2.5 %) flowered 2 years after acclimatization. This was approximately half the time required to flower for most of the remaining progeny. This novel progeny showed gains in most morphological characteristics evaluated relative to their parents. One of the hybrids obtained (‘BR501’) flowered four times a year and had ornamentally and horticulturally important characteristics related to pot-flower production, including novel color, compact plant size, a greater number and larger inflorescences and flowers. This hybrid can be included in further breeding programs of the Cattleya hybrid group.

FIRST REPORT OF MYROTHECIUM RORIDUM CAUSING ROUND SPOT ON DENDROBIUM CANDIDUM IN CHINA

Dendrobium candidum (family Orchidaceae) is grown as a medicinal plants in China. In July 2013, in some plastic greenhouses of Puer (Southwest Yunnan) round spots were observed on the leaves of D. candidum plants with 20-30% incidence. Initial symptoms included black to brown circular or subcircular lesions 0.5-2.0 cm in diameter, surrounded by water-soaked tissue and later by concentric rings, grey brown and dark green. Infected leaves turned yellow, wilted, and decayed. Symptomatic leaf tissues (4x5 mm fragments) were surface-sterilized and cultured onto potato dextrose agar (PDA) at 25°C in darkness. Developing colonies were white, floccose at the beginning, then produced sporodo- chia in dark greyish-green concentric rings bearing slimy spore masses. Conidia were smooth, hyaline, cylindrical with rounded ends, 4.9-8.9x1.4-2.8 μm in size. DNA was extracted from a fungal isolate denoted YNPE-SH9 using a DNA extraction kit (OMEGA, USA). The internal tran- scribed spacer (ITS) region and 5.8S rDNA gene were am- plified using primer pair of ITS1 and ITS4 (White et al., 1990). BLAST search of the obtained sequence (GenBank accession No. KM986033) revealed a 100% identity with two Myrothecium roridum strains (AJ301995, AJ302001). Leaves of 10 healthy greenhouse-grown D. candidum plants at the seedling stage were inoculated by injecting a conidial sus- pension of M. roridum (1.1×105 conidia per ml) and kept at 28°C, 80% relative humidity and 14-h photoperiod. Seed- lings inoculated with sterile distilled water served as con- trols. Symptoms like those seen in naturally infected plants were observed in all inoculated D. candidum seedlings seven days post inoculation while control plants remained symp- tomless. To our knowledge, this is the first report of natural infection by M. roridum on Dendrobium spp. in China.

PENGARUH NAA DAN BAP TERHADAP PERTUMBUHAN SUBKULTUR ANGGREK HASIL PERSILANGAN Dendrobium biggibum X Dendrobium liniale

&lt;p&gt;&lt;em&gt;Indonesia has a high diversity of species of orchids. One of them is the Dendrobium orchid. Orchid seeds do not have endosperm should be grown in a medium that has enough nutrients. Orchid propagation in vitro is strongly influenced by the composition of the medium used. Research through experiments aimed at studying the effect of NAA, BAP, NAA and BAP combination of the subculture plantlets growth of &lt;/em&gt;&lt;em&gt;hybrids&lt;/em&gt;&lt;em&gt; orchid Dendrobium biggibum X liniale in Vacin Went media. Research conducted at the Laboratory of Tissue Culture Center for Plant Conservation Bogor Botanical Gardens. &lt;/em&gt;&lt;em&gt;The experimental design used was completely randomized design (CRD) with two factors. The first factor was the concentration of Naphthalene Acetic Acid /NAA ( 0 ppm, 1 ppm, 3 ppm and 5 ppm). The second factor was the type media of &lt;/em&gt;&lt;em&gt;Benzyl Amino Purine&lt;/em&gt;&lt;em&gt; /BAP ( 0 ppm, 1 ppm, 3 ppm and 5 ppm). &lt;/em&gt;&lt;em&gt;Each treatment was replicated eight times. Analysis of the data by F test level 5% and if there is a significant difference continued with Duncan Multiple (Duncan's Multiple Range Test) level of 5%. The result showed that &lt;/em&gt;&lt;em&gt;the addition &lt;/em&gt;&lt;em&gt;of NAA 3 ppm &lt;/em&gt;&lt;em&gt;as much as 4,96 cm &lt;/em&gt;&lt;em&gt; and BAP 3 ppm &lt;/em&gt;&lt;em&gt;as much as 4,41 cm &lt;/em&gt;&lt;em&gt; give a significant effect on the increase of high plantlets&lt;/em&gt;&lt;em&gt; &lt;/em&gt;&lt;em&gt;and so NAA 3 ppm &lt;/em&gt;&lt;em&gt;as much as 5,76 cm &lt;/em&gt;&lt;em&gt; effect on roots length , but did not significantly effect the number of leaves and roots.&lt;/em&gt;&lt;/p&gt;

Overexpression of an Orchid (Dendrobium nobile) SOC1/TM3-Like Ortholog, DnAGL19, in Arabidopsis Regulates HOS1-FT Expression.

Flowering in the appropriate season is critical for successful reproduction in angiosperms. The orchid species, Dendrobium nobile, requires vernalization to achieve flowering in the spring, but the underlying regulatory network has not been identified to date. The MADS-box transcription factor DnAGL19 was previously identified in a study of low-temperature treated D. nobile buds and was suggested to regulate vernalization-induced flowering. In this study, phylogenetic analysis of DnAGL9 and the MADS-box containing proteins showed that DnAGL19 is phylogenetically closely related to the SOC1-like protein from orchid Dendrobium Chao Parya Smile, DOSOC1. The orchid clade closed to but is not included into the SOC1-1/TM3 clades associated with either eudicots or monocots, suggesting that DnAGL19 is an SOC1-1/TM3-like ortholog. DnAGL19 was found to be highly expressed in pseudobulbs, leaves, roots, and axillary buds but rarely in flowers, and to be substantially upregulated in axillary buds by prolonged low-temperature treatments. Overexpression of DnAGL19 in Arabidopsis thaliana resulted in a small but significantly reduced time to bolting, suggesting that flowering time was slightly accelerated under normal growth conditions. Consistent with this, the A. thaliana APETELA1 (AP1) gene was expressed at an earlier stage in transgenic lines than in wild type plants, while the FLOWERING LOCUS T (FT) gene was suppressed, suggesting that altered regulations on these transcription factors caused the weak promotion of flowering. HIGH EXPRESSION OF OSMOTICALLY RESPONSIVE GENE 1 (HOS1) was slightly activated under the same conditions, suggesting that the HOS1-FT module may be involved in the DnAGL19-related network. Under vernalization conditions, FT expression was significantly upregulated, whereas HOS1 expression in the transgenic A. thaliana has a level similar to that in wild type. Taken together, these results suggest that DnAGL19 controls the action of the HOS1-FT module depending on temperature cues, which could contribute to regulation of D. nobile flowering time. These data provide insights into how flowering is fine-tuned in D. nobile to acclimate the plant to seasonal changes in temperature.

Effect of Banana Extract on Growth and Development of Protocorm Like Bodies in &lt;i&gt;Dendrobium&lt;/i&gt; sp. orchid

An experiment was carried out in Plant Tissue Culture Laboratory, Department of Crop Botany, Bangladesh Agricultural University, Mymensingh to investigate the effect of banana extract on micropropagation of &lt;i&gt;Dendrobium&lt;/i&gt; sp. var. Sonia orchid through PLBs. The experiment was conducted during July 2012 to October 2013. Half-Murashige and Skoog (1/2MS) medium were used as basal medium and the medium was supplemented with banana extract at 12.5, 25, 50, 100, and 200 ml L-1 with a control, where no banana extract was supplemented. The cultures were done in 100 ml conical flasks and maintain at 25°C with 30µ mol m-2 S-1 lighting provided by florescent tubes for 16 hours per day. Banana extract showed significant effect on growth and development of PLBs. Among the treatments, 100 ml L-1 banana extract enhanced new PLBs regeneration from explanted PLBs and growth and development of PLBs. Present research indicated that nutrient requirement for PLBs multiplication and plantlets growth of Dendrobium orchid is quantitatively different in vitro. Finally, 100 ml L-1 and 25 ml L-1 of banana extract may be recommended as supplement into 1/2MS medium for PLBs multiplication and plantlet regeneration, respectively in vitro.The Agriculturists 2015; 13(1) 101-108

Methods for genetic transformation in Dendrobium.

The genetic transformation of Dendrobium orchids will allow for the introduction of novel colours, altered architecture and valuable traits such as abiotic and biotic stress tolerance. The orchid genus Dendrobium contains species that have both ornamental value and medicinal importance. There is thus interest in producing cultivars that have increased resistance to pests, novel horticultural characteristics such as novel flower colours, improved productivity, longer flower spikes, or longer post-harvest shelf-life. Tissue culture is used to establish clonal plants while in vitro flowering allows for the production of flowers or floral parts within a sterile environment, expanding the selection of explants that can be used for tissue culture or genetic transformation. The latter is potentially the most effective, rapid and practical way to introduce new agronomic traits into Dendrobium. Most (69.4 %) Dendrobium genetic transformation studies have used particle bombardment (biolistics) while 64 % have employed some form of Agrobacterium-mediated transformation. A singe study has explored ovary injection, but no studies exist on floral dip transformation. While most of these studies have involved the use of selector or reporter genes, there are now a handful of studies that have introduced genes for horticulturally important traits.