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The use of plant growth regulators has led to environmental contamination of water bodies that occur adjacent to agricultural areas. Some of these chemicals are bioactive, not only to plants, but also to non-target exposed biota, namely of the aquatic compartment. Previous work demonstrated the establishment of hepato- and nephrotoxic effects in juvenile tilapia (Oreochromis niloticus) exposed via aquatic media to gibberellic acid (GA3), which is among the most used plant growth regulators, in agricultural practices. Here, we investigated the effect of GA3 on hematological indices, poikilocytosis, nuclear abnormalities, and genotoxic indices measured in Nile tilapia (Oreochromis niloticus), as well as the putative protective effects of dietary supplementation of Spirulina (Arthrospira platensis). Fish were evenly assorted into 5 groups: group I served as a control, and groups II-V were fed diets supplemented with Spirulina at rates of 0 g/kg, 5 g/kg, 20 g/kg, and 100 g/kg, respectively, for 2 months before being exposed to 150 mg/L GA3. The results revealed that GA3 exposure decreased significantly all hematological indices (P < 0.05), except leucocytes and mean corpuscular hemoglobin concentration (MCHC), compared to the control group (P > 0.05). GA3 exposure increased significantly the percentage of nuclear abnormalities, altered erythrocytes and the percentages of tail DNA, compared to the control group (P < 0.05). Spirulina supplementation restored the hematological, poikilocytosis, nuclear abnormalities, and the percentages of tail DNA to near normal levels. The 100 g/kg SP treatment was the most effective in attaining such effect, showing concentration-dependency. The present study reinforces our findings of the toxicity of GA3 on O. niloticus and suggests that the addition of Spirulina to fish diet can mitigate the hemotoxic effects of GA3.
Assuntos
Ciclídeos , Spirulina , Tilápia , Animais , Reguladores de Crescimento de Plantas , Suplementos Nutricionais , Dieta , Ração Animal/análiseRESUMO
Sorghum ("Jitian 3") is a salt-tolerant seed cultivar used regularly in marginal lands, such as those with saline soils. Herein, we examined the potential of employing gibberellic acid (GA3) as an inducer of sorghum development during salt stress. Thus far, there have been no reports on the signaling network involved in the GA3-mediated regulation of sorghum development. In this study, we demonstrated that the stimulating properties of 50 mg/L GA3 on sorghum development was far superior to other GA3 concentrations under a 150 mM NaCl salinity condition. Furthermore, using methylated RNA immunoprecipitation sequencing (MeRIP-seq), we established an m6A methylation (m6A-M) profile in sorghum following exposure to 50 mg/L GA3. Overall, 23,363 m6A peaks and 16,200 m6A genes were screened among the GA3-treated and control leaves. These identified peaks were shown to be primarily enriched in the coding, as were the 3'- and 5'-untranslated regions. In addition, we employed m6A and transcript expression cross-analysis to identify 70 genes with differential transcript expression and simultaneous m6A-M. Intriguingly, the principal gene, LOC8066282, which is associated with LOC8084853, was shown to be intricately linked to the phosphatidylinositol signaling, which in turn regulates sorghum development and response to salt stress. This investigation presents a novel RNA m6A-M profile in sorghum, which may facilitate new insights into the underlying signaling behind salt stress resistance. This work will also benefit future investigations on foreign GA3 administration of sorghum.
Assuntos
Sorghum , Epigenoma , Perfilação da Expressão Gênica , Fosfatidilinositóis/metabolismo , RNA/metabolismo , Estresse Salino/genética , Cloreto de Sódio/metabolismo , Cloreto de Sódio/farmacologia , Solo , Sorghum/metabolismo , Transcriptoma , Regiões não TraduzidasRESUMO
Male reproductive development in higher plants experienced a series of complex biological processes, which can be regulated by Gibberellins (GA). The transcriptional factor GAMYB is a crucial component of GA signaling in anther development. However, the mechanism of GAMYB in wheat male reproduction is less understood. Here, we found that the thermo-sensitive genic male sterilitywheat line YanZhan 4110S displayed delayed tapetum programmed cell death and pollen abortive under the hot temperature stress. Combined with RNA-Sequencing data analysis, TaGAMYB associated with fertility conversion was isolated, which was located in the nucleus and highly expressed in fertility anthers. The silencing of TaGAMYB in wheat displayed fertility decline, defects in tapetum, pollen and exine formation, where the abortion characteristics were the same as YanZhan 4110S. In addition, either hot temperature or GA3 treatment in YanZhan 4110S caused the downregulation of TaGAMYB at binucleate stage and trinucleate stage, as well as fertility decrease. Further, the transcription factor TaWRKY2 significantly changed under GA3-treatment and directly interacted with the TaGAMYB promoter by W-box cis-element. Therefore, we suggested that TaGAMYB may be essential for anther development and male fertility, and GA3 activates TaGAMYB by TaWRKY2 to regulate fertility in wheat.
Assuntos
Fenômenos Biológicos , Oryza , Regulação da Expressão Gênica de Plantas , Giberelinas/metabolismo , Oryza/genética , Pólen , RNA , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Triticum/genética , Triticum/metabolismoRESUMO
Salvia miltiorrhiza is a medicinal plant that synthesises biologically-active tanshinones with numerous therapeutic properties. An important rate-limiting enzyme in the biosynthesis of their precursors is 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGR). This study presents the organ-specific expression profile of the S. miltiorrhiza HMGR4 gene and its sensitivity to potential regulators, viz. gibberellic acid (GA3), indole-3-acetic acid (IAA) and salicylic acid (SA). In addition, it demonstrates the importance of the HMGR4 gene, the hormone used, the plant organ, and the culture environment for the biosynthesis of tanshinones. HMGR4 overexpression was found to significantly boost the accumulation of dihydrotanshinone I (DHTI), cryptotanshinone (CT), tanshinone I (TI) and tanshinone IIA (TIIA) in roots by 0.44 to 5.39 mg/g dry weight (DW), as well as TIIA in stems and leaves. S. miltiorrhiza roots cultivated in soil demonstrated higher concentrations of the examined metabolites than those grown in vitro. GA3 caused a considerable increase in the quantity of CT (by 794.2 µg/g DW) and TIIA (by 88.1 µg/g DW) in roots. In turn, IAA significantly inhibited the biosynthesis of the studied tanshinones in root material.
Assuntos
Salvia miltiorrhiza , Salvia , Abietanos , Acil Coenzima A , Coenzima A , Furanos , Oxirredutases/metabolismo , Fenantrenos , Raízes de Plantas/genética , Raízes de Plantas/metabolismo , Quinonas , Salvia miltiorrhiza/metabolismoRESUMO
Melatonin production is induced by many abiotic and biotic stressors; it modulates the levels of many plant hormones and their signaling pathways. This study investigated the effects of plant hormones on melatonin synthesis. Melatonin synthesis in rice seedlings was significantly induced upon exogenous gibberellin 3 (GA3) treatment, while it was severely decreased by GA synthesis inhibitor paclobutrazol. In contrast, abscisic acid (ABA) strongly inhibited melatonin synthesis, whereas its inhibitor norflurazon (NF) induced melatonin synthesis. The observed GA-mediated increase in melatonin was closely associated with elevated expression levels of melatonin biosynthetic genes such as TDC3, T5H, and ASMT1; it was also associated with reduced expression levels of catabolic genes ASDAC and M2H. In a paddy field, the treatment of immature rice seeds with exogenous GA led to enhanced melatonin production in rice seeds; various transgenic rice plants downregulating a GA biosynthesis gene (GA3ox2) and a signaling gene (Gα) showed severely decreased melatonin levels, providing in vivo genetic evidence that GA has a positive effect on melatonin synthesis. This is the first study to report that GA is positively involved in melatonin synthesis in plants; GA treatment can be used to produce melatonin-rich seeds, vegetables, and fruits, which are beneficial for human health.
Assuntos
Melatonina , Oryza , Ácido Abscísico/metabolismo , Regulação da Expressão Gênica de Plantas , Giberelinas/metabolismo , Giberelinas/farmacologia , Humanos , Melatonina/metabolismo , Melatonina/farmacologia , Oryza/metabolismoRESUMO
In this study, we determined the effect of hormonization treatment on yield quantity and quality, content of biologically active compounds, and antioxidant activity in fruits and raisins of 'Einset Seedless' grapevine. Field studies were conducted in 2017 at Nobilis Vineyard (50°39' N; 21°34' E) in the Sandomierz Upland. Analytical studies were carried out in the Laboratory of the University of Life Sciences in Lublin. Hormonized fruits and raisins, which were dried at 40 °C in a food dryer for 7 days, were the experimental material. It was shown that the application of the hormonization treatment had a significant effect on yield size and quality. The hormonization treatment and the form of plant material analyzed had a significant effect on the content of biologically active compounds and the antioxidant activity in 'Einset Seedless' grapevine fruits and raisins. The concentration of applied gibberellic acid had a significant effect on the levels of acidity, content of anthocyanins, and antioxidant activity determined with the FRAP and DPPH methods. The application of the multivariate analysis technique showed that, in the fresh fruits and raisins, the level of biologically active compounds and antioxidant activity in the case of the 200 mgâGA3âL-1 concentration and in the control combination was similar but differed significantly in the case of the 300 mgâGA3âL-1 application.
Assuntos
Vitis/química , Antocianinas/análise , Antioxidantes/análise , Alimentos em Conserva/análise , Frutas/química , Frutas/efeitos dos fármacos , Frutas/crescimento & desenvolvimento , Giberelinas/administração & dosagem , Fenóis/análise , Extratos Vegetais/análise , Reguladores de Crescimento de Plantas/farmacologia , Vitis/efeitos dos fármacos , Vitis/crescimento & desenvolvimentoRESUMO
We used exogenous GA_3 to break the seed dormancy of Thesium chinense. We used high-throughput sequencing technology was used to sequence the transcriptome of dormant seed embryos and dormancy breaking seed embryos of Th. chinense, and the data was analyzed bioinformatically and systematically. The results showed that exogenous GA_3 could effectively break the seed dormancy of Th. chinense; 73 794 up-regulated genes and 42 776 down regulated genes were obtained by transcriptome sequencing; 116 570 diffe-rential genes were annotated by GO function to GO items such as metabolism process, cell process, cell, cell component, binding and catalytic activity. A total of 133 metabolic pathways were found by Pathway analysis of 26 508 differentially expressed genes. In the process of dormancy release, DEGs were mainly enriched in translation, carbohydrate metabolism, folding, classification, degradation and amino acid metabolism. Based on the annotation results in KEGG database, 20 metabolic pathways related to dormancy release were found. Dormancy release of Th. chinense seeds is a complex biological process, including cell morphology construction, secondary metabolite synthesis, sugar metabolism and plant signal transduction, among which plant hormone signal transduction is one of the key factors to regulate dormancy release. The results of qRT-PCR showed that the sequencing results were consistent with the actual results.
Assuntos
Dormência de Plantas , Santalaceae , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Reguladores de Crescimento de Plantas , Sementes , TranscriptomaRESUMO
SUGCT (C7orf10) is a mitochondrial enzyme that synthesizes glutaryl-CoA from glutarate in tryptophan and lysine catabolism, but it has not been studied in vivo. Although mutations in Sugct lead to Glutaric Aciduria Type 3 disease in humans, patients remain largely asymptomatic despite high levels of glutarate in the urine. To study the disease mechanism, we generated SugctKO mice and uncovered imbalanced lipid and acylcarnitine metabolism in kidney in addition to changes in the gut microbiome. After SugctKO mice were treated with antibiotics, metabolites were comparable to WT, indicating that the microbiome affects metabolism in SugctKO mice. SUGCT loss of function contributes to gut microbiota dysbiosis, leading to age-dependent pathological changes in kidney, liver, and adipose tissue. This is associated with an obesity-related phenotype that is accompanied by lipid accumulation in kidney and liver, as well as "crown-like" structures in adipocytes. Furthermore, we show that the SugctKO kidney pathology is accelerated and exacerbated by a high-lysine diet. Our study highlights the importance of non-essential genes with no readily detectable early phenotype, but with substantial contributions to the development of age-related pathologies, which result from an interplay between genetic background, microbiome, and diet in the health of mammals.
Assuntos
Envelhecimento , Coenzima A-Transferases/genética , Microbioma Gastrointestinal , Síndrome Metabólica/patologia , Animais , Antibacterianos/farmacologia , Bactérias/genética , Bactérias/isolamento & purificação , Carnitina/análogos & derivados , Carnitina/metabolismo , Coenzima A-Transferases/deficiência , Suplementos Nutricionais , Fezes/microbiologia , Microbioma Gastrointestinal/efeitos dos fármacos , Humanos , Rim/metabolismo , Rim/patologia , Metabolismo dos Lipídeos , Fígado/metabolismo , Fígado/patologia , Lisina/administração & dosagem , Síndrome Metabólica/metabolismo , Metaboloma/efeitos dos fármacos , Camundongos , Camundongos Knockout , Obesidade/metabolismo , Obesidade/patologia , Triptofano/metabolismoRESUMO
In order to explore appropriate measures to promote germination after the harvest of Epimedium pseudowushanense, 6-BA, urea, ammonium bicarbonate and GA3 were chosen to spray on the root and rhizomes, and then the biological indicators such as branches, leaf length, leaf width, plant height and so on, were measured in different periods, and the contents of epimedin A, epimedin B, epimedin C and icariin in the dry leaves were detected by HPLC. Results showed that 6-BA 90 mg·L⻹(B1), 6-BA 60 mg·L⻹(B2),6-BA 30 mg·L⻹+urea 300 mg·L⻹ (C1), 6-BA 60 mg·L⻹+urea 300 mg·L⻹(C2),6-BA 60 mg·L⻹+ ammonium bicarbonate 300 mg·L⻹(C4) significantly increased bud germination in the early period, and the plants quickly set up new system of photosynthesis, the branches in a month of which were higher than the control group respectively by 165.9%, 115.76%, 103.86%, 104.50%, 81.67%.However the branches developed the next year and the dry weight of leaves per plant in group B1 and B2 were much lower than that in control group. The groups that use 6-BA and nitrogen at the same time reaped a good yield of leaves even though the treatment had no significant influence on the branches developed the next year. The dry weight of leaves of C1, C2, C4 treatments were 36.80%, 32.84%, 45.97% more than the control group respectively. Therefore, C1, C2 and C4 treatments are the more appropriate to promote recovery after harvest. Furthermore, different groups, except 10 mg·L⻹ 6-BA treatment significantly reduced the content of epimedin C, other groups didn't have any significant effect on the contents of such flavonoids.
Assuntos
Epimedium/efeitos dos fármacos , Nitrogênio/farmacologia , Reguladores de Crescimento de Plantas/farmacologia , Epimedium/crescimento & desenvolvimento , Flavonoides/análise , Folhas de Planta/crescimento & desenvolvimentoRESUMO
Adhatoda vasica Nees, belonging to family Acanthaceae, is a well-known medicinal plant. It is endorsed for its pyrroloquinazoline alkaloids and its derivatives, such as vasicine and vasicinone. Germinating A. vasica seeds is a tedious task; on that account, vegetative propagation is the preferred method for its multiplication. For rapid and large-scale multiplication, germplasm conservation as well as secondary metabolites production, in vitro culture of A. vasica was preferred over conventional propagation by several researchers; however, some major applications of this tissue culture technique are still awaiting to undergo extensive research. The present review, for the first time, illustrates all the major achievements associated with in vitro regeneration of A. vasica, reported till date and highlights the future prospects.
RESUMO
Objective: To clone the gibberellin 3-oxidase gene DoGA3ox from an important and endangered medicinal plant Dendrobium officinale (Orchidaceae), followed by bioinformatic and expression analysis. Methods: RACE and RT-PCR were used to isolate the full-length gene. The physicochemical properties, conserved domains, and subcellular localization of DoGA3ox protein were determined using a series of bioinformatic tools. The phylogenetic analyses were performed using DNASTAR 7.0 and MEGA 6.0 software. Real time quantitative PCR was employed for gene expression analysis. Results: The full-length cDNA of DoGA3ox (GenBank registration number KT597694) was 1 318 bp in size, and encoded a 353-amino acid peptide chain with a molecular weight of 39052.5 and an isoelectric point (pI) of 6.21; The deduced DoGA3ox protein without transmembrane or signal peptide residues, contained the gibberellin 3-oxidases conserved domains that DIOX_N (40-130) and 2OG-FeII_Oxy (197-299). DoGA3ox had 51%-56% similarity with GA3ox proteins from various plants, and was closely related to the monocot Allium fistulosum, Elaeis guineensis, and Phoenix dactylifera. The relative transcript levels of DoGA3ox were increased at stage 1, then decreased (stage 2), and increased again (stage 3) during D. officinale symbiotic/asymbiotic seed germination, the fold change to ungerminated seeds was 13.44 (symbiotic)/5.21 (asymbiotic), 7.28/2.32 and 9.40/6.21, respectively. Moreover, its transcript level was higher in symbiotic germination than that in the asymbiotic status. Conclusion: The full-length DoGA3ox gene is cloned for the first time, and its expression in different stages during seed germination indicates that DoGA3ox gene plays a crucial role in the regulation of seed germination in D. officinale.
RESUMO
BACKGROUND: Hypoxis hemerocallidea, arguably the most well-known medicinal species in South Africa, has been the subject of intensive harvesting from the wild leading to recent conservation concerns. The seeds of this species do not propagate easily and can lie dormant for up to twelve months. MATERIALS AND METHODS: In the in vitro germination experiments water, acid and chemical pre-sowing treatments were performed to determine the germination response of this species in both light and dark conditions. In the ex vitro experiment, intact seeds were sown and left to germinate in a potting soil mix under greenhouse conditions. RESULTS: Highest levels of germination (36.7-60.0% in the light and 36.7-46.7% in the dark) were achieved by treating mechanically scarified seeds with GA3 at various concentrations for 24 h. This was followed by scarified seeds soaked in water (26.7% in the light and 23.3% in the dark). Similar results (23.3 and 26.7%) were obtained in the 1% and 4% KNO3 treatments, respectively, under light conditions only. The fastest time to germinate was two days and was obtained in the 1200 ppm GA3 treatment in both light and dark conditions. Ex vitro germination of H. hemerocallidea seeds under greenhouse conditions was unsuccessful. CONCLUSION: H. hemerocallidea displays physical and non-deep physiological dormancy where pre-sowing treatments are required before the seeds will germinate.
Assuntos
Giberelinas/farmacologia , Hypoxis/efeitos dos fármacos , Hypoxis/crescimento & desenvolvimento , Dormência de Plantas/efeitos dos fármacos , Reguladores de Crescimento de Plantas/farmacologia , Hypoxis/efeitos da radiação , Luz , Sementes/efeitos dos fármacos , Sementes/crescimento & desenvolvimento , Sementes/efeitos da radiação , TemperaturaRESUMO
ETHNOPHARMACOLOGICAL RELEVANCE: The genus Eucomis (Hyacinthaceae) consists of 10 species that are extensively used in African traditional medicine. This review is an appraisal of current information on the distribution and morphology, traditional uses, pharmacology, toxicology and approaches devised to enhance the conservation of the genus. METHODS: A systematic and comprehensive literature search using electronic searches such as Scopus, Google Scholar, Web of Science and ethnobotanical books was conducted. RESULTS: Evidence from traditional medicine usage shows wide utilization of this genus for ailments such as respiratory, venereal diseases, rheumatism as well as kidney and bladder infections. Pharmacological screening reported antimicrobial, antiplasmodial, antitumor, cytotoxic, phytotoxic and anti-inflammatory properties. CONCLUSIONS: The potential of the genus Eucomis especially in terms of pharmacology cannot be overemphasized. Apart from the anti-inflammatory properties, the antifungal activity of Eucomis remains a valuable reservoir with potential application in the agriculture sector as a source of an affordable biocontrol agent. Based on the speculated toxic constituents in the genus Eucomis, it will be valuable to conduct detailed toxicological studies. Extensive utilization of members of the genus Eucomis is causing severe strain on wild populations. Although conventional propagation has been relatively effective in the alleviation of the declining status, micropropagation of members may be vital to guarantee the conservation of wild populations.
Assuntos
Conservação dos Recursos Naturais , Liliaceae/química , Liliaceae/fisiologia , Preparações de Plantas/química , Preparações de Plantas/uso terapêutico , África Subsaariana , Humanos , Medicinas Tradicionais AfricanasRESUMO
Oil palm protoplasts are suitable as a starting material for the production of oil palm plants with new traits using approaches such as somatic hybridization, but attempts to regenerate viable plants from protoplasts have failed thus far. Here we demonstrate, for the first time, the regeneration of viable plants from protoplasts isolated from cell suspension cultures. We achieved a protoplast yield of 1.14×10(6) per gram fresh weight with a viability of 82% by incubating the callus in a digestion solution comprising 2% cellulase, 1% pectinase, 0.5% cellulase onuzuka R10, 0.1% pectolyase Y23, 3% KCl, 0.5% CaCl2 and 3.6% mannitol. The regeneration of protoplasts into viable plants required media optimization, the inclusion of plant growth regulators and the correct culture technique. Microcalli derived from protoplasts were obtained by establishing agarose bead cultures using Y3A medium supplemented with 10µM naphthalene acetic acid, 2µM 2,4-dichlorophenoxyacetic acid, 2µM indole-3-butyric acid, 2µM gibberellic acid and 2µM 2-γ-dimethylallylaminopurine. Small plantlets were regenerated from microcalli by somatic embryogenesis after successive subculturing steps in medium with limiting amounts of growth regulators supplemented with 200mg/l ascorbic acid.
Assuntos
Arecaceae/fisiologia , Meios de Cultura , Reguladores de Crescimento de Plantas/farmacologia , Técnicas de Embriogênese Somática de Plantas/métodos , Protoplastos/fisiologia , Arecaceae/crescimento & desenvolvimento , Divisão Celular , Óleo de Palmeira , Óleos de Plantas , Protoplastos/citologia , Protoplastos/efeitos dos fármacos , Regeneração , SefaroseRESUMO
The production of anthocyanins in the tomato (Solanum lycopersicum L.) fruit is normally absent or poor, but a number of mutants or introgression lines are known to increase anthocyanin levels in vegetative and reproductive tissues. Through conventional breeding, a genetic combination was obtained with the remarkable phenotype of a deep purple fruit pigmentation, due to an accumulation of anthocyanins on the peel. Such a genotype was named Sun Black (SB) as a consequence of its sensitivity to light induction. When characterized for morpho-agronomic traits, SB plants showed increased fertility. Purple fruits displayed an arrangement of the epicarp cells different from normal tomatoes, a feature that could account for different mechanical properties and shelf-life potential. The SB genotype and, to a lesser extent, its single mutant parents showed the capacity to accumulate anthocyanins in the seedling root when grown under light. This phenotype, which was greatly improved by the addition of sucrose to the germination medium, proved to be useful as selection index and gave new insights for in vitro production of anthocyanin extracts. To assess the nutraceutical potential of purple tomatoes, we tested the activity of SB skin extracts on the proliferation of two human cancer cells lines. Cell proliferation was significantly inhibited by SB extract in a dose-dependent manner. When the bioactivity of SB extracts was compared with that of other anthocyanin-containing fruits or vegetables, a significant "Extract*Line" interaction was evidenced, suggesting a crucial role for the extract composition in terms of anthocyanidins and other eventual cell growth-inhibiting compounds.
Assuntos
Frutas/metabolismo , Solanum lycopersicum/metabolismo , Antocianinas/metabolismo , Antioxidantes/metabolismo , Cruzamento , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Frutas/química , Humanos , Solanum lycopersicum/química , Fenótipo , Extratos Vegetais/química , Extratos Vegetais/farmacologiaRESUMO
O presente trabalho teve como objetivo estudar a influência dos reguladores vegetais BAP e GA3 como tratamentos pré-germinativos no processo de germinação e desenvolvimento inicial de plântulas de Dendrobium nobile, espécie importante pelas propriedades farmacológicas como anti-oxidante, vasodilatadora e até mesmo anti-cancerígena, além do valor ornamental. Os tratamentos pré-germinativos consistiram de BAP e GA3, separadamente, nas concentrações de 0,0; 1,0; 2,0 e 5,0 mg L-1. Após seis meses da semeadura in vitro e manutenção em câmara de germinação e de crescimento com temperatura e foto-período controlados (12 horas e 23ºC ± 2), foram avaliados os parâmetros número de sementes germinadas, porcentagem de germinação, massa fresca e altura das plântulas, diâmetro e número de pseudobulbos, número de folhas, número de raízes, e o comprimento da maior raiz. O delineamento experimental foi inteiramente casualizado. Todas as variáveis foram submetidas à análise de variância e de regressão, quando significativas. As sementes de D. nobile germinaram melhor na ausência de reguladores vegetais e os tratamentos com BAP ou GA3 na embebição das sementes pouco beneficiaram o desenvolvimento in vitro de D. nobile.
The present study aimed to investigate the influence of plant growth regulators BAP and GA3 as pre-germinative treatment in the process of germination and initial development of seedlings of Dendrobium nobile, a species important for its pharmacological properties like antioxidant, vasodilator and even anticancer, besides its ornamental value. Pre-germinative treatments consisted of BAP and GA3, separately, at the concentrations of 0.0; 1.0; 2.0 and 5.0 mg L-1. At six months after in vitro sowing and maintenance in a germination and growth chamber with controlled temperature and photoperiod (12 hours and 23ºC ± 2), the following parameters were evaluated: number of germinated seeds, percentage of germination, fresh mass and height of seedlings, number and diameter of pseudo-bulbs, number of leaves, number of roots, and length of the largest root. The experimental design was completely randomized. All variables underwent analysis of variance and regression analysis when significant. D. nobile seeds presented better germination in the absence of plant growth regulators and the treatments with BAP or GA3 in seed imbibition little benefited D. nobile in vitro development.