Dendrobium Research Articles

Correlation between cane growth and flowering behavior of Dendrobium orchid cultivars

The experiment was conducted to observe the correlation of cane growth with floral behavior of nine Dendrobium cultivars. Results revealed that, cane growth of different Dendrobium cultivars influenced flowering behavior. The present experimental findings may help to determine standard cane growth for efficient nutrient management and commercial grade flower production of Dendrobium cultivars. DOI: http://dx.doi.org/10.3329/jbas.v37i2.17561 Journal of Bangladesh Academy of Sciences, Vol. 37, No. 2, 205-209, 2013

In vitro growth and multiplication of a hybrid orchid Dendrobium alba Ascanda dongtarm with different concentration of plant growth regulators

In vitro growth and multiplication of a hybrid orchid Dendrobium alba Ascanda dongtarm with different concentration of plant growth regulators

Effects of NPK and 6-Benzylaminopurine on Growth and Flowering of Two Orchid Genera

The rising demand for herbal medicine and environmental degradation necessitates the development of more productive management practices for many valuable orchid species. The nitrogen, phosphorous and potassium (NPK) fertilisation and 6-benzylaminopurine (BAP) application has been advised as a practice to address these trends. However, it is not known that at what rate the plant would efficiently endorse the growth. Performance of three NPK ratios, viz., (10:10:10), (20:10:15) and (30:10:15), with three dosages, i.e. 1, 2 and 3 g/l, for each ratio and nine concentrations, i.e. 15, 25, 50, 75, 100, 125, 150, 175 and 200 mg/l, of BAP supplement on two rare orchids Dendrobium densiflorum and Phaius tankervilleae was evaluated in green house conditions. At 1 g/l of (30:10:15) ratio NPK application, both the species showed significantly highest plant height, leaf length, leaf width and number of leaves. Shortest time interval from inflorescence emergence to first flower opening was observed when 200 mg/l of BAP was applied. The results indicate that NPK with high N and K promote vegetative growth and the cytokinin (BAP), at a concentration of 200 mg/l, has a great potential for speeding up flowering process in both the genera.

Ultrastructure of symbiotic germination of the orchid Dendrobium officinale with its mycobiont, Sebacina sp.

Dendrobium officinale is an endangered epiphytic orchidaceous medicinal plant. Similar to other orchid plants, the seed germination of D. officinale under natural conditions depends nutritionally upon mycorrhizal fungi. The compatible fungi have been isolated from D. officinale protocorms using in situ seed baiting technique in our previous studies. However, the interaction between seed germination of D. officinale and its mycobiont is still unclear. In the present study, we investigated the morphological changes of seed and fungus during the symbiotic germination using a light microscope and transmission electron microscope. Seeds of D. officinale have no conspicuous suspensor cells. The fungus enters into the embryo cell through the posterior end of the embryo and colonises the cortical cell in the first stage of germination (Stage 1). Then, the hyphae form pelotons with the protocorm development (Stages 1–3). After protocorm formation, the reinvaded fungal hyphae conspicuously decrease. Invaded hyphae lose bioactivity, form clumps and start degeneration at Stage 4 or 5 (seedling development). When penetrating the neighbouring cortical cell, the fungal hyphae constrict to collar shape at the contacted site and follow by swelling in the apex. Our study suggested that fungi trigger protocorm development and concomitant reserve utilisation during the symbiotic germination.

Retraction Note: Synthetic seed technology for short term conservation of medicinal orchid Dendrobium densiflorum Lindl. Ex Wall and assessment of genetic fidelity of regenerants

Artificial seeds were obtained through encapsulation of protocorm-like bodies (PLBs) of Dendrobium densiflorum in calcium alginate beads. This paper demonstrates the alginate-encapsulation and conversion (complete plantlet regeneration) from PLBs, the effect of storage conditions (at different temperature; 4, 8, 16 °C, RT and duration; 15, 30, 45, 60, 75, 90 days) on viability of encapsulated plant materials as well as the assessment of genetic fidelity of the regenerants. Individual PLBs were encapsulated in calcium alginate beads for mass propagation, short-term storage and germplasm sharing. The superior gel matrix for encapsulation was obtained using 3 % sodium alginate and 100 mM calcium chloride (CaCl2·2H2O). The highest percentage of conversion (100 %) of encapsulated PLBs (capsules) was obtained on MS2 medium (MS medium + 2 mg/l BAP). Capsules were successfully stored till 60 days at 8 °C with conversion frequency of 95.5 %. Plantlets regenerated from encapsulated beads were acclimatized successfully with 95 % survival rate. A total of 40 primers were screened, out of which 10 primers successfully generated 39 scorable bands, ranging from 0.2 to 1.3 kb amplicons. The uniform RAPD banding profile among the plantlets derived from encapsulated PLBs following 60 days of storage confirmed genetic fidelity.

Moscatilin Induces Apoptosis and Mitotic Catastrophe in Human Esophageal Cancer Cells

Moscatilin, a bibenzyl derivative from the orchid Dendrobium loddigesii, has been shown to possess anticancer activity. We examined the effect of moscatilin on human esophageal cancer cells, including squamous cell carcinoma (SCC) and adenocarcinoma (ADC) cells and its possible mechanisms. Moscatilin suppressed the growth of both the histological cell lines in a dose- and time-dependent manner. Morphological changes indicative of apoptosis and mitotic catastrophe were observed following moscatilin treatment. The population of cells in the sub-G1 phase and polyploidy phase significantly increased after treatment. Immunofluorescence revealed multipolar mitosis and subsequent multinucleation in moscatilin-treated cells, indicating the development of mitotic catastrophe. Western blot showed a marked increase in expressions of polo-like kinase 1 and cyclin B1 after exposure to moscatilin. In conclusion, moscatilin inhibits growth and induces apoptosis and mitotic catastrophe in human esophageal SCC- and ADC-derived cell lines, indicating that moscatilin has broad potential against esophageal cancer.

<b>Propagation of Noble Dendrobium (<i>Dendrobium nobile</i> Lindl.) by cutting</b> - doi: 10.4025/actasciagron.v35i4.15198

The Noble Dendrobium orchid (Dendrobium nobile Lindl.) is an ornamental species usually propagated by leaf axillary shoots called “Keikes”, but cutting is possible although, many do not produce leaves or roots and eventually rot. To increase the proportion of successful stalk cuttings, two substrates were evaluated in the present study (gravel and a 1:1 tree-fern shredded trunk:palm seed mixture) in interaction with the application of nitrogen fertilizer (urea 2 g L-1) and a commercial leaf fertilizer made from kelp seaweed (“Kelpak” a 2 mL L-1). Only water was applied for the control treatment. The evaluated parameters included the proportion of successful cuttings, vigor, the proportion of rotten stalks, the number of roots/plant and root length/per plant. The gravel was found to be the best substrate for the rooting and/or shoot production (37.2% in average) of the cuttings. The application of urea or Kelpak induced vigor in the obtained plantlets, but the dosage required for a greater efficiency was not reached. The cuttings layered on gravel plus the application of urea at a concentration of 2 g L-1 was the most effective treatment, with 40.7% successful cuttings.

Efeito do silício na qualidade de flores de Dendrobium nobile (Orchidaceae)

The orchid Dendrobium nobile Lindl is widely cultivated throughout the world as cut and potted flowers. Silicon (Si) has demonstrated beneficial effects on various crops, increasing cell stiffness, giving protection to pathogens, increasing photosynthetic capacity and drought tolerance, promoting higher growth and longevity. The aim of this study was to evaluate the effect of different concentrations of silicon on Dendrobium nobile orchid flowers. Treatments were performed with magnesium silicate (SiMg) at the following concentrations: 0.0, 0.16; 0.32; 0.48 and 0.64 g L-1. The foliar applications were carried out fortnightly totaling four applications two months before flowering. The variables evaluated were: longevity of flowers, number of flowers per pot and number of shoots per plant. The experimental design was completely randomized with five treatments and ten replications. The foliar applications of SiMg increased 59% flower production and shoots up to 66%, being more efficient with the increasing of concentrations. The increasing of longevity of the flowers in the dose 0.45 g L-1 was up to four days.

In vitro growth and carbon utilization of the green-leaved orchid Dendrobium officinale are promoted by mycorrhizal associations.

BackgroundMycorrhizal associations play a key role in the life cycle and evolutionary history of orchids. All orchids grow from extremely small seeds that are lacking in reserves, and germination and growth into an underground heterotrophic, achlorophyllous stage depend upon symbiotic fungi to provide nutrient. However, the nutritional physiology between this symbiosis and green-leaved orchids is still unclear. To understand further how these associations affect growth and carbon utilization of green orchids, the green orchids were inoculated with two symbiotic fungi isolated from the roots of a wild orchid (Dendrobium officinale) in vitro and 13C stable isotope signature experiments were designed to analyze carbon nutrition acquisition.ResultsAfter two months, both fungi had formed mycorrhizal associations with the host roots. Moreover, the growth rate was more rapid for the mycorrhizal seedlings than for the non-mycorrhizal seedlings. The mycorrhizal seedlings not only absorbed more 13C from the substrate, but also the S3-mycorrhizal seedlings assimilated more atmospheric 13CO2 due to significantly higher effective quantum yield of photosystem II, compared with the non-mycorrhizal seedlings. These results suggested that the green orchids could receive more C nutrition from the substrate due to symbiotic fungi, and photosynthesis capacity of the green D. officinale could be enhanced by the S3 fungus, therefore carbon nutrition acquisition also increased. As a result, the S1- and S3- mycorrhizal seedlings showed markedly higher biomass and polysaccharides contents than the non-mycorrhizal seedlings.ConclusionsThese results improve our understanding of the mycorrhizal functioning in the green Dendrobium and show some potential application in the cultivation of D. officinale.Electronic supplementary materialThe online version of this article (doi:10.1186/1999-3110-54-23) contains supplementary material, which is available to authorized users.

Erratum to: Synthetic seed technology for short term conservation of medicinal orchid Dendrobium densiflorum Lindl. Ex Wall and assessment of genetic fidelity of regenerants

Erratum to: Synthetic seed technology for short term conservation of medicinal orchid Dendrobium densiflorum Lindl. Ex Wall and assessment of genetic fidelity of regenerants

Isolation of an actin promoter for strong expression of transgenes in the orchid genus Dendrobium

We isolated and functionally characterized a Dendrobium Actin1 (DmACT1) promoter that drives strong gene expression in the orchid genus Dendrobium. A genomic fragment containing the region 3227 bp upstream of the coding region of DmACT1 was obtained by inverse PCR. Detailed comparison of the full-length cDNA and genomic sequences revealed that DmACT1 has a 1374 bp first intron in the 5' UTR. However, the 5' flanking sequences upstream of the coding region showed no obvious sequence similarities compared to those of known promoters, including plant actin promoters. Serial deletion constructs of the 5' flanking region from the translation initiation codon were fused to the coding sequence of a GUS/luciferase fusion reporter to identify the regulatory elements necessary for promoter activity. Transient assays in the flowers of Dendrobium revealed that the 5' UTR-intron greatly enhanced promoter activity. Moreover, the DmACT1 promoter with its 5' UTR-intron yielded approximately 10-fold higher reporter activity than the rice Act1 promoter-intron. Our data suggest that the DmACT1 promoter with its 5' UTR-intron is a useful tool for strong expression of transgenes in Dendrobium orchids.

RETRACTED ARTICLE: Synthetic seed technology for short term conservation of medicinal orchid Dendrobium densiflorum Lindl. Ex Wall and assessment of genetic fidelity of regenerants

RETRACTED ARTICLE: Synthetic seed technology for short term conservation of medicinal orchid Dendrobium densiflorum Lindl. Ex Wall and assessment of genetic fidelity of regenerants

Overexpression of DOSOC1, an Ortholog of Arabidopsis SOC1, Promotes Flowering in the Orchid Dendrobium Chao Parya Smile

SUPPRESSOR OF OVEREXPRESSION OF CONSTANS1 (SOC1) encodes a MADS-box protein that plays an essential role in integrating multiple flowering signals to regulate the transition from vegetative to reproductive development in the model plant Arabidopsis. Although SOC1-like genes have been isolated in various angiosperms, its orthologs in Orchidaceae, one of the largest families of flowering plants, are so far unknown. To investigate the regulatory mechanisms of flowering time control in orchids, we isolated a SOC1-like gene, DOSOC1, from Dendrobium Chao Praya Smile. DOSOC1 was highly expressed in reproductive organs, including inflorescence apices, pedicels, floral buds and open flowers. Its expression significantly increased in whole plantlets during the transition from vegetative to reproductive development, which usually occurred after 8 weeks of culture in Dendrobium Chao Praya Smile. In the shoot apex at the floral transitional stage, DOSOC1 was particularly expressed in emerging floral meristems. Overexpression of DOSOC1 in wild-type Arabidopsis plants resulted in early flowering, which was coupled with the up-regulation of two other flowering promoters, AGAMOUS-LIKE 24 and LEAFY. In addition, overexpression of DOSOC1 was able partially to complement the late-flowering phenotype of Arabidopsis soc1-2 loss-of-function mutants. Furthermore, we successfully created seven 35S:DOSOC1 transgenic Dendrobium orchid lines, which consistently exhibited earlier flowering than wild-type orchids. Our results suggest that SOC1-like genes play an evolutionarily conserved role in promoting flowering in the Orchidaceae family, and that DOSOC1 isolated from Dendrobium Chao Praya Smile could serve as an important target for genetic manipulation of flowering time in orchids.

EFFECT OF DIFFERENT MATURITY STAGES ON THE DISPLAY-LIFE OF CUT DENDROBIUM ORCHIDS

Dendrobium orchid inflorescences are the most important cut flower for exports. The experiment was to investigate the vase-life of cut Dendrobium 'Suree White' and Dendrobium 'Suree Peach' 115 inflorescences at different stages of development. Inflorescences of both cultivars were harvested from the Mana Orchid nursery at four different stages of development and were transported to the laboratory at Silpakorn University within one hour. The four different stages were determined as following; stage 1 had 25% open flowers, stage 2 had 40% open flowers, stage 3 had 50% open flowers and stage 4 had 75% open flowers per inflorescence where the 40% open stage serves as the commercial stage. The stem ends were re-cut to ensure a uniform size before placing in distilled water at 25°C for the evaluation of vase-life. The results showed that cut inflorescences of Dendrobium 'Suree White' at different stages of development did not affect its vase-life, while the inflorescences of Dendrobium 'Suree Peach' 115 cut at 25% of open florets had a longer vase-life (approximately 10 days) compared with other stages (8, 6 and 5 days, respectively).

Cryopreservation of pharmaceutically important orchid Dendrobium chrysanthum Wall. ex Lindl. using vitrification based method

Our present study constitutes the successful and efficient protocol for cryopreservation of Dendrobium chrysanthum. D. chrysanthum Wall. ex Lindl. is a pharmaceutically valuable, ornamental epiphytic orchid of temperate and subtropical regions. On account of excellent herbal medicinal value and horticultural importance, D. chrysanthum is becoming rare due to over exploitation. For long-term conservation of this orchid, protocorm-like bodies of D. chrysanthum were excised and used for cryopreservation by encapsulation–vitrification. In this cryogenic procedure, PLBs were initially osmoprotected with a mixture of 0.4 M sucrose and 2 M glycerol, incorporated in the encapsulation matrix (comprising of 3 % (w/v) sodium alginate and 0.1 M CaCl2). Encapsulated protocorm-like bodies (PLBs) were then precultured on MS liquid medium supplemented with different concentrations of sucrose (0.06, 0.3, 0.5, 0.7 M), and loaded in a loading solution (comprised of 2 M glycerol and 0.4 M sucrose) for different duration to make the precultured PLBs tolerant to plant vitrification solution 2 (PVS2). Subsequently, the PLBs were subjected to PVS2 (Sakai et al. 1990) treatment at different time of exposure (minutes) and temperatures (0 °C and 25 °C). Encapsulated–vitrified PLBs were plunged directly into liquid nitrogen and stored for 1 h. Optimum result (survival 63.2 % and regrowth 59.9 %) was obtained when the beads treated with loading solution for 80 min followed by PVS2 treatment for 100 min. Regenerated plants showed normal morphology as that of control plants.

UJI BEBERAPA ISOLAT Trichoderma sp UNTUK MENGEP«)ALIKAN PENYAKITBUSUKmTAMPADATANAMANANGGREK DENDROBIUM

Objective of this research was to test the ability of Trickottermasp isolate andget the best isolate incontrolling blighted leave disease on dendrobium orchid. TUs research was conducted cxperimentelly usingCompletely Randondzed Design (RAL) byfivetreatments of TridHHlerma sp isoUte (TO « without TrichuJennmsp,TI 'isotateT-ag,T2-=T-«a,T3>T-k,T4'^b). Resultof research indicates that application of some isolateon dendrobium orchid gives different influence hi controlling blighted leave disease on orchid. In controllingPhytopktkon sp.. Isolate T-ag is better because it has stronger hihibition ability.

Genetic Variability and Character Association in Some Native Orchid Species (<i>Dendrobium spp.</i>)

An experiment was carried out using 20 native Dendrobium orchids in Completely Randomized Design (CRD) with three replications at the Orchidarium of Landscape, Ornamental and Floriculture Division, HRC, BARI, Gazipur during the period January 2007 to June 2007 to estimate genetic variability, genetic parameters and correlation coefficient among different flower components. Highly significant variations were observed among the genotypes for all the characters. High broad sense heritability with high genetic advance was observed in spike length (94.00% and 98.29), rachis length (95.34% and 93.85), flower durability (94.00% and 89.00) and floret number (70.50% and 65.47) indicating additive gene action, suggesting the possibility of improvement of these traits through selection. Other characters exhibited moderate broad sense heritability with low genetic advance. The number of florets per spike recorded a highly significant association with flower durability, rachis length and spike length. Durability of flower had significant positive correlation with rachis length, flower size and spike length at both genotypic and phenotypic level. Highly significant positive correlation was also found between rachis length and spike length. However, the correlation study revealed that selection of parents should be done based on characters such as floret number, rachis length and flower durability which would be useful in a breeding program. The path analysis revealed that rachis length, durability of flower and number of flowers per spike had contributed maximum direct effects on flower yield, indicating the importance of these three characters as selection criteria for native Dendrobium orchid. DOI: http://dx.doi.org/10.3329/agric.v10i1.11058 The Agriculturists 2012; 10(1): 1-9

Postharvest responses of cut Dendrobium orchids to exogenous ethylene

The time to senescence of flowers in Dendrobium hybrids is different and one of the major reasons for this variation in vase life can be related to differences in the level of ethylene sensitivity. This study was conducted to determine the sensitivity of six cut Dendrobium hybrids to exogenous ethylene. The cut orchid inflorescences were treated with or without 10 μL/L ethylene gas for 24 h, and then placed in bottles containing a standard vase solution. Water loss, vase life, anthocyanin contents and ethylene production were determined after the treatments. The results indicated that different hybrids showed distinct variances in ethylene sensitivities and degrees of deterioration. Dendrobium ‘Darren Glory’ and D. ‘Jaquelyne Concert’ × D. ‘Rinappa’ exhibited the utmost hyponasty, weight loss and degradation of anthocyanin content in sepals and petals. Thus, these two hybrids were categorized as the very sensitive group. On the other hand, D. ‘Sonia Red ’, D. ‘Shavin White’ , D. ‘Sonia White’ and D. ‘Sonia Bom ’ showed lower sensitivity and hence were categorized in the less sensitive group. The results of this experiment and similar experiments to determine the resistant and susceptible cultivars to ethylene injury can be helpful in improving the postharvest life of cut orchid flowers. Key words: Ethylene sensitivity, vase life, anthocyanin content, ACC synthase, ACC oxidase.

In vitro plantlet regeneration from protocorms of Dendrobium lituiflorum Lindl. and Cymbidium bicolor Lindl. and their acclimatisation: effect of salts, sucrose, and banana extract

SummaryThe salts present in modified Knudson C (KC) medium (1946), 2% (w/v) sucrose, and a natural banana extract (BE) [1 – 20% (v/v)] were studied singly, or in combination, for their effects on the regeneration of protocorms of the orchid species, Dendrobium lituiflorum and Cymbidium bicolor. The incorporation of KC salts along with higher percentages of BE [10% or 20% (v/v)] promoted protocorm development as well as shoot and root formation. The presence of 2% (w/v) sucrose in the medium further enhanced root lengths and the rooting percentage, irrespective of the presence of KC salts. Incorporation of both KC salts and 2% (w/v) sucrose was found to be obligatory, in conjunction with BE (a cost-effective natural additive) for plantlet regeneration. In vitro-raised plantlets of both orchid species exhibited high rates of survival under greenhouse conditions. Scanning electron microscopy revealed elliptical stomata and epicuticular granular wax deposits on their abaxial leaf surfaces after acclimatisation.

Deferring flowering of nobile dendrobium hybrids by holding plants under low temperature after vernalization

Orchids are currently the most valuable potted crop in the United States. To date, no studies focused on making possible the year-round greenhouse production of flowering nobile dendrobium orchids. This experiment was aimed at developing a strategy to defer flowering of nobile dendrobium orchids by holding them under low temperature. Mature Den. Red Emperor ‘Prince’ and Den. Sea Mary ‘Snow King’ were held at 10 °C for various durations (0, 4, 8, 12 or 16 weeks) after vernalization (4 weeks at 10 °C). Plants were forced in a greenhouse after holding. Time to flower, flower differentiation (flowering node percentage, number of aerial shoot and aborted bud) and flower quality (total flower number, flower diameter, flower number per flowering node and flower longevity) were determined. Increase of low temperature holding duration from 0 to 16 weeks extended time to flower up to 3 months and did not affect parameters of flower except producing larger flowers and reducing flower number per flowering node for Den. Red Emperor ‘Prince’. Notably, the flower longevity was not adversely affected. Defoliation was aggravated in Den. Red Emperor ‘Prince’ by longer duration of cooling and was considered a detrimental effect of low temperature holding.