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Natural pigments are components very important in the dye industry. The betalains are pigments found in plants from Caryophyllales order and are relevant in the food manufacturing. The main source of betalains is beetroot, which has unfavorable aftertaste. Therefore, the demand for alternative species producing betalains has increased. Elicitor molecules such as methyl jasmonate (MeJA) induce metabolic reprogramming acting in the biosynthesis of specialized metabolites and can enhance pigment concentrations. Here, we used this strategy to identify if treatment with MeJA at 100 µM can promote the accumulation of betalains and other bioactive compounds in Alternanthera philoxeroides and Alternanthera sessilis. We performed the gene expression, concentration of betalains, phenols, flavonoids, amino acids (phenylalanine and tyrosine), and antioxidant activity. The results showed that MeJA treatment increased betalains and other bioactive compounds in the two Alternanthera species but A. sessilis had a better performance. One key factor in this pathway is related to the phenylalanine and tyrosine concentration. However, the species have distinct metabolic regulation: in A. philoxeroides, high concentrations of betalain pigments increase the tyrosine concentration and gene expression (include ADH) under MeJA and in A. sessilis, high concentrations of betalain pigments reduce the gene expression and tyrosine concentration after 2 days under MeJA. This study brings new questions about betalain biosynthesis and sheds light on the evolution of this pathway in Caryophyllales.
Assuntos
Amaranthaceae , Betalaínas , Pigmentos Biológicos , Amaranthaceae/genética , Amaranthaceae/metabolismo , Betalaínas/biossíntese , Pigmentos Biológicos/análise , Fenilalanina , Tirosina , Redes e Vias Metabólicas , Regulação da Expressão Gênica de Plantas , Flavonoides/análise , Fenóis/análise , Antioxidantes/análiseRESUMO
Drought is a pivotal cause for crop yield reductions. When subjected to recurrent external stimuli, plants can develop memory of stress responses that, eventually, enables improved plant tolerance to environmental changes. In addition, despite causal relationships, these responses may vary according to hierarchical levels of observation. Thus, this study aims to check the responses of recurrent and non-recurrent stresses in two rice genotypes observing their drought memory responses at different levels of organization, that is, on a physiological, biochemical and metabolomic scale and for end in global PCA. For this, seventy variables were measured on the scales described in order to obtain a large number of observations. The memory responses were evident in almost all scales observed. The lowland genotype, especially plants not subjected to recurrent water shortage, showed higher damage to the photosynthetic apparatus under drought conditions, although it has exhibited more evident memory response effect after rehydration. On the other hand, the upland genotype appears to be more tolerant to drought insofar lower biochemical damage was observed. Specific behaviors of each genotype at biochemical and metabolomics levels and similar behavior at physiological level were observed. This study demonstrates the importance of observation at different hierarchical levels.
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Adaptação Fisiológica/genética , Desidratação/genética , Desidratação/fisiopatologia , Secas , Oryza/genética , Oryza/fisiologia , Água/metabolismo , Brasil , Produtos Agrícolas/genética , Produtos Agrícolas/fisiologia , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Variação Genética , Genótipo , Estresse Fisiológico/genéticaRESUMO
Plants are constantly exposed to environmental fluctuations, that may occur in a single day or over longer periods. In many cases, abiotic stresses are transient and recurrent, impacting how plants respond in subsequent adverse conditions. Adaptation mechanisms may occur at the physiological, biochemical and molecular level, modifying transcriptional response, regulatory proteins, epigenetic marks or metabolites. Here, we aimed to uncover the different strategies that rice uses to respond to recurrent stress. We tested varieties with contrasting behavior towards salinity (tolerance or sensitivity) and imposed salt stress (150 mM NaCl) during 48 h at vegetative and/or reproductive stages. After 48 h of stress in reproductive stage, leaves and roots were harvested separately or otherwise the plants were submitted to a 24 h recovery, prior to sample harvesting. Plants submitted to a recurrent stress responded differently from those suffering a single stress event. In the case of the sensitive genotype, recurrent stress led to lower Na/K ratio in roots and lower hydrogen peroxide accumulation and lipid peroxidation in leaves, but maintenance of global DNA methylation levels. In the tolerant genotype, recurrent stress did neither affect the Na/K ratio nor the stomatal conductance, although the levels of superoxide anion and hydrogen peroxide accumulation were lower, as also observed for global levels of DNA methylation. Our work shows that a short pre-exposure to salt stress may improve rice tolerance to subsequent stress, trough biochemical, physiological and epigenetic processes, with more significant changes visible in the tolerant genotype.
Assuntos
Oryza/genética , Epigênese Genética , Regulação da Expressão Gênica de Plantas , Genótipo , Salinidade , Estresse FisiológicoRESUMO
Stevia rebaudiana is an important source of natural steviol glycosides and is of increasing interest in various fields of study. Therefore, understanding the molecular processes regulating its metabolism is of great importance. In this study, the stability of seven reference genes (18S ribosomal RNA, Actin, Aquaporin, Calmodulin, Eukaryote elongation factor 1-α, Malate dehydrogenase, and Ubiquitin) under the effect of three stress-related elicitors (methyl jasmonate, salicylic acid, and spermidine) was evaluated in stevia plants. We used RefFinder software, which makes use of the four main currently available algorithms for reference gene selection: geNorm, NormFinder, BestKeeper, and the Comparative ∆Ct method. The results indicated that Ubiquitin and Actin can be used as reference genes under all tested experimental conditions. The genes, 18S ribosomal RNA, traditionally used as a reference gene, along with Calmodulin, showed the lowest stability. The expression of Deoxyxylulose-5-phosphate synthase and Kaurenoic acid hydroxylase genes was used to confirm the validated reference genes, showing that inadequacy of the reference gene may lead to erroneous results. This is the first study on the stability of reference genes in Stevia rebaudiana plants, and is of great relevance for further analysis of the gene expression of the steviol glycoside biosynthetic pathway.
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The rice cultivar (Oryza sativa L.) BRS AG, developed by Embrapa Clima Temperado, is the first cultivar designed for purposes other than human consumption. It may be used in ethanol production and animal feed. Different abiotic stresses negatively affect plant growth. Soil salinity is responsible for a serious reduction in productivity. Therefore, the objective of this study was to evaluate the gene expression and the activity of antioxidant enzymes (SOD, CAT, APX and GR) and identify their functions in controlling ROS levels in rice plants, cultivar BRS AG, after a saline stress period. The plants were grown in vitro with two NaCl concentrations (0 and 136 mM), collected at 10, 15 and 20 days of cultivation. The results indicated that the activity of the enzymes evaluated promotes protection against oxidative stress. Although, there was an increase of reactive oxygen species, there was no increase in MDA levels. Regarding genes encoding isoforms of antioxidant enzymes, it was observed that OsSOD3-CU/Zn, OsSOD2-Cu/Zn, OsSOD-Cu/Zn, OsSOD4-Cu/Zn, OsSODCc1-Cu/Zn, OsSOD-Fe, OsAPX1, OsCATB and OsGR2 were the most responsive. The increase in the transcription of all genes among evaluated isoforms, except for OsAPX6, which remained stable, contributed to the increase or the maintenance of enzyme activity. Thus, it is possible to infer that the cv. BRS AG has defense mechanisms against salt stress.
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MAIN CONCLUSION: The set of variables analyzed as integrated by multivariate analysis of principal components consistently showed a memory effect induced by the drought pre-treatment in AN Cambará plants. The effects of drought can vary ddepending on many factors. Among these the occurrence of a previous water stress may leave a residual effect (memory), influencing the future performance of a plant in response to a new drought event. This study tested the hypothesis that plants experiencing recurrent drought would show more active mechanisms of water deficit tolerance, mainly plants of the genotype that is cultivated often experiencing water shortages periods. Additionally, all the plants subjected to water deficit were rehydrated by 24 h and the expression of transcription factors related to drought responses was re-evaluated. To this end, the water status of two rice genotypes, BRS Querência (flooded) and AN Cambará (dryland), was evaluated to identify molecular alterations likely underpinning drought-memory. In growth stage V5, some plants were exposed to water stress (10% VWC soil moisture-pre-treatment). Thereafter, the pots were rehydrated at the same level as the control pots and maintained under this condition until drought was reapplied (10% VWC) at the reproductive stage (R1-R2). Then, the plants were rehydrated and maintained at pot capacity for 24 h. Overall, the set of variables analyzed integrally by multivariate analysis of principal components consistently showed a memory effect induced by the drought pre-treatment in AN Cambará plants (the dryland genotype). This conclusion, based on data of the biochemical and molecular analyses, was supported by the greater capacity of maintenance of the water status by stomatal regulation of the pre-treated and rehydrated plants after the second drought stimulus.
Assuntos
Regulação da Expressão Gênica de Plantas , Oryza/fisiologia , Estresse Fisiológico , Antioxidantes/metabolismo , Desidratação , Secas , Perfilação da Expressão Gênica , Genótipo , Peróxido de Hidrogênio/metabolismo , Peroxidação de Lipídeos , Oryza/genética , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Estômatos de Plantas/genética , Estômatos de Plantas/fisiologia , Prolina/metabolismo , Solo , Água/fisiologiaRESUMO
Among the compounds produced by plants, pigments such as betalains have received attention from both food and pharmaceuticals industries. The Alternanthera sessilis species produces these pigments, though in small quantities, and so it is necessary to increase production. Thus, many studies use elicitors that are capable of triggering physiological or morphological responses in plants. The objective was to establish callus production in A. sessilis grown under different combinations of growth regulators and light qualities and to assess whether these factors can increase betalain and flavonoid production. Leaf and internodal explants in MS medium with different growth regulators were used to obtain calli, which were subsequently transferred to a betacyanin induction medium remaining for 40 days under different light qualities (white, blue, red, and dark). The most suitable treatment for callus formation and subsequent betalain and flavonoid induction was to combine a medium containing 6.7 µmol L-1 2,4-D and 9.0 µmol L-1 BAP and blue light. Physical elicitation by light combined with appropriate concentration of growth regulators on calli can increase production of commercially important metabolites.
Dentre os compostos produzidos pelas plantas, os pigmentos, como as betalaínas, vêm recebendo destaque tanto pela indústria alimentícia como farmacêutica. A espécie Alternanthera sessilis produz esses pigmentos, porém em pequenas quantidades, sendo necessário incrementar a produção. Para isso, muitos estudos utilizam elicitores que são capazes de desencadear respostas fisiológicas ou morfológicas nas plantas. O objetivo do trabalho foi estabelecer a produção de calos de A. sessilis crescidos quando submetidos a diferentes combinações de reguladores de crescimento e qualidades de luz, e avaliar se esses fatores são capazes de incrementar a produção de betalaínas e flavonoides. Foram utilizados explantes foliares e internodais em meio MS com diferentes reguladores de crescimento para obtenção dos calos que, posteriormente, foram transferidos para meio de indução de betacianina, onde permaneceram por 30 dias sob diferentes qualidades de luz (branca, azul, vermelha e escuro). O tratamento mais propício para formação de calos e consequente indução de betalaínas e flavonoides foi a combinação do meio contendo 6,7 µmol L-1 2,4-D e 9,0 µmol L-1 BAP e a luz azul. Conclui-se que a elicitação física pela luz em conjunto com a concentração adequada de reguladores de crescimento em calos é capaz de incrementar a produção de metabólitos de interesse comercial.
Assuntos
Betalaínas , Flavonoides , Plantas MedicinaisRESUMO
Many studies use strategies that allow for the identification of a large number of genes expressed in response to different stress conditions to which the plant is subjected throughout its cycle. In order to obtain accurate and reliable results in gene expression studies, it is necessary to use reference genes, which must have uniform expression in the majority of cells in the organism studied. RNA isolation of leaves and expression analysis in real-time quantitative polymerase chain reaction (RT-qPCR) were carried out. In this study, nine candidate reference genes were tested, actin 11 (ACT11), ubiquitin conjugated to E2 enzyme (UBC-E2), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), beta tubulin (ß-tubulin), eukaryotic initiation factor 4α (eIF-4α), ubiquitin 10 (UBQ10), ubiquitin 5 (UBQ5), aquaporin TIP41 (TIP41-Like) and cyclophilin, in two genotypes of rice, AN Cambará and BRS Querência, with different levels of soil moisture (20%, 10% and recovery) in the vegetative (V5) and reproductive stages (period preceding flowering). Currently, there are different softwares that perform stability analyses and define the most suitable reference genes for a particular study. In this study, we used five different methods: geNorm, BestKeeper, ΔCt method, NormFinder and RefFinder. The results indicate that UBC-E2 and UBQ5 can be used as reference genes in all samples and softwares evaluated. The genes ß-tubulin and eIF-4α, traditionally used as reference genes, along with GAPDH, presented lower stability values. The gene expression of basic leucine zipper (bZIP23 and bZIP72) was used to validate the selected reference genes, demonstrating that the use of an inappropriate reference can induce erroneous results.
Assuntos
Genes de Plantas , Oryza/genética , Água/fisiologia , Regulação da Expressão Gênica de Plantas , Genótipo , Oryza/fisiologia , RNA de Plantas/genética , Reação em Cadeia da Polimerase em Tempo Real , Padrões de Referência , SoftwareRESUMO
Abiotic stresses such as salinity, iron toxicity, and low temperatures are the main limiting factors of rice (Oryza sativa L.) yield. The elucidation of the genes involved in responses to these stresses is extremely important to understand the mechanisms that confer tolerance, as well as for the development of cultivars adapted to these conditions. In this study, the RNA-seq technique was used to compare the transcriptional profile of rice leaves (cv. BRS Querência) in stage V3, exposed to cold, iron, and salt stresses for 24 h. A range of 41 to 51 million reads was aligned, in which a total range of 88.47 to 89.21 % was mapped in the reference genome. For cold stress, 7905 differentially expressed genes (DEGs) were observed, 2092 for salt and 681 for iron stress; 370 of these were common to the three DEG stresses. Functional annotation by software MapMan demonstrated that cold stress usually promoted the greatest changes in the overall metabolism, and an enrichment analysis of overrepresented gene ontology (GO) terms showed that most of them are contained in plastids, ribosome, and chloroplasts. Saline stress induced a more complex interaction network of upregulated overrepresented GO terms with a relatively low number of genes compared with cold stress. Our study demonstrated a high number of differentially expressed genes under cold stress and a greater relationship between salt and iron stress levels. The physiological process most affected at the molecular level by the three stresses seems to be photosynthesis.
Assuntos
Oryza/genética , Proteínas de Plantas/biossíntese , Estresse Fisiológico/genética , Transcriptoma/genética , Temperatura Baixa , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Ferro/toxicidade , Oryza/crescimento & desenvolvimento , Proteínas de Plantas/genética , Cloreto de Sódio/toxicidade , Transcriptoma/efeitos dos fármacosRESUMO
This research investigates effects of salicylic acid (an abiotic elicitor) on the antioxidant activity and betacyan production from leaves of Alternanthera tenella cultured in vitro was evaluated. Plants were grown in a liquid MS medium and vermiculite substrate. After 35 days salicylic acid was added to the medium. Content of betacyanins, total phenols and flavonoids and non-enzymatic antioxidant capacity were determined in leaves of A. tenella after 0, 12, 36 and 48h of treatment. After 36h, concentration of betacyanins and total phenols increased. On the other hand, the increase of the treatment time caused a slight decrease in total flavonoids and reduced the DPPH free radical activity. As result the antioxidant activity of the leaves of A. tenella is promoted by salicylic acid and can be attributed to the increase in betacyanin content, which are compounds with recognized antioxidant action.
Este trabalho investiga o efeito do ácido salicílico (um elicitor abiótico) sobre a atividade antioxidante e produção de betacianinas em folhas de Alternanthera tenella cultivada in vitro. As plantas foram cultivadas em meio MS líquido e vermiculita como substrato. Após 35 dias, o ácido salicílico foi adicionado ao meio. Conteúdo de betacianinas, fenóis totais e flavonoides e a capacidade antioxidante não-enzimática foi determinada em folhas de A. tenella após 0, 12, 36 e 48h de tratamento. Após 36h, a concentração de betacianinas e fenóis totais aumentaram. Em contrapartida, o aumento no tempo de exposição causou uma ligeira diminuição nos teores de flavonoides totais e inibição da atividade do radical livre DPPH. Como resultado, a atividade antioxidante de folhas de A. tenella é promovida pelo ácido salicílico e pode ser atribuída ao aumento do conteúdo de betacianina, os quais são compostos com ação antioxidante reconhecida.
RESUMO
The aim of the present study was to investigate the influence of tyrosine on the in vitro growth and the production of the betacyanin pigment in Alternanthera philoxeroides and A. tenella. Nodal segments were inoculated in MS medium containing different concentrations of tyrosine (0, 25, 50 and 75 μM), and the number of sprouts and buds, height, root length, fresh matter of shoots and roots and betacyanin content were evaluated. In A. philoxeroides , the highest production of betacyanin (51.30 mg 100 g-1 FM) was in the stems with the addition of approximately 45 μM tyrosine, while the increase in the leaves was proportional to the tyrosine concentration, and the best average was obtained with a tyrosine concentration of 75 μM (15.32 mg 100 g-1 FM). Higher tyrosine concentrations were deleterious to the growth of A. tenella plants, and a concentration of 75 μM was considered toxic. However, a tyrosine concentration of 50 μM benefitted betacyanin production, which reached 36.5 mg 100 g-1 FM in the plant shoots. These results showed the positive effect of tyrosine on the production of betacyanin in both species; however, application at high concentrations hampered the growth of Alternanthera plants.
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Techniques used to induce mutations, such as ionizing radiation, are an effective tool in increasing genetic variability in breeding programs of species of economic interest. This study aimed to evaluate the effect of different doses of Co60 gamma radiation on previously soaked seeds on the emergence and early growth of seedlings of two rice cultivars. To do this, seeds (25 percent moisture) of BRS Querência and BRS Fronteira were irradiated with zero (control), 50, 100, 150 and 200 Gy, and then sown in trays containing soil and kept in a greenhouse. The results showed that gamma radiation affected seedling development, where the highest dose tested (200 Gy) significantly reduced the emergence and the index of emergence speed. Growth parameters were reduced greater reduction in cv. BRS Querência. For antioxidant enzymes, superoxide dismutase expressed little variation for the periods evaluated. Already ascorbate peroxidase and catalase showed a significant increase in horsepower cv. BRS Fronteira at 14 DAS, followed by an increase in both cultivars ascorbate peroxidase activity at 28 DAS. The highest antioxidant capacity observed in cv. BRS Fronteira conferred greater tolerance to stress caused by gamma radiation.
Técnicas como radiações ionizantes, utilizadas para induzir mutações constituem ferramenta eficaz no aumento de variabilidade genética em programas de melhoramento de espécies de interesse econômico. Neste trabalho, objetivou-se verificar o efeito de diferentes doses de radiação gama Co60 em sementes previamente embebidas sobre a emergência e o crescimento inicial de plântulas de duas cultivares de arroz. Lotes de sementes com 25 por cento de umidade das cultivares BRS Querência e BRS Fronteira foram irradiados com doses de zero (controle), 50, 100, 150 e 200 Gy, sendo, em seguida, semeadas em bandejas contendo solo e mantidas em casa de vegetação. Os resultados mostraram que a radiação gama afetou o desenvolvimento das plântulas, sendo que a maior dose testada (200 Gy) reduziu, significativamente, a emergência e o índice de velocidade de emergência. Os parâmetros de crescimento apresentaram maior redução na cv. BRS Querência. Na atividade das enzimas antioxidantes, a superóxido dismutase expressou pouca variação para os períodos avaliados. Já, a ascorbato peroxidase e catalase mostraram expressivo aumento na cv. BRS Fronteira aos 14 DAS, seguidas de incremento para as duas cultivares na atividade da ascorbato peroxidase aos 28 DAS. A maior capacidade antioxidante observada na cv. BRS Fronteira conferiu uma maior tolerância ao estresse causado pela radiação gama.
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A shoot regeneration system for Plectranthus neochilus was studied from leaf explants. Leaves developed under in vitro conditions were cultured on Wood Plant Medium supplemented with 0.2mg dm-3 α-naphthaleneacetic acid (NAA) and different 6-benzilaminopurine (BAP) or thidiazuron (TDZ) concentrations (0, 1.5, 3.0, 4.5 and 6.0mg dm-3). An increase in percentage of responsive explants (85.3 percent) and in the number of shoots developed per explant (3.2) was observed when the explants were treated with 5.3 and 4.7mg dm-3 BAP, respectively. The leaf explants cultured on media supplemented with TDZ became vitreous and did not form buds. The regeneration system used is efficient for boldo bud induction and shoot development, showing high potential for advanced cellular and molecular studies.
O objetivo do presente trabalho foi adequar um protocolo de regeneração a partir de explantes foliares de Plectranthus neochilus. Folhas desenvolvidas sob condições in vitro foram cultivadas em meio WPM suplementado com 0,2mg L-1 de ácido α-naftaleno acético (ANA) e diferentes concentrações (0; 1,5; 3,0; 4,5 e 6,0mg L-1) de 6-benzilaminopurina (BAP) ou thidiazuron (TDZ). Observou-se o aumento na percentagem de explantes regenerantes (85,3 por cento) e no número de brotações por explante (3,2), quando os explantes foliares foram cultivados em meio contendo 5,3 e 4,7mg L-1 de BAP, respectivamente. Os explantes foliares cultivados em TDZ tornaram-se vítreos e não formaram gemas. O protocolo utilizado é eficiente para a indução de gemas e brotações, demonstrando a potencialidade de seu uso para estudos mais avançados de biologia celular e molecular.
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A manipulação da concentração dos microelementos no meio de cultura representa uma boa estratégia para aumentar a produção de metabólitos secundários em cultura de tecidos. Este trabalho teve por objetivo demonstrar a influência do sulfato de cobre na produção de betacianina e na multiplicação de plantas de Alternanthera philoxeroides (erva-de-jacaré) cultivadas in vitro. Segmentos nodais, obtidos de plantas pré-estabelecidas e após três subcultivos, foram inoculados em meio MS, com diferentes concentrações de CuSO4 (0; 25; 75; 125; 175; 200µM). O delineamento experimental utilizado foi inteiramente casualizado, com seis concentrações de CuSO4 e cinco repetições representadas por um frasco contendo quatro explantes. Os resultados foram submetidos à análise de variância, à regressão polinomial e a análises de correlação entre as variáveis morfológicas e a produção de betacianina. Concentrações acima de 75µM diminuíram a altura das plantas, o número de brotos e gemas e o crescimento radicular, enquanto que, na concentração de 125µM, houve a maior produção de massa fresca. A produção de betacianina aumentou 60 por cento em relação ao controle com 175µM de CuSO4. Ocorreu crescimento das plantas em todas as concentrações de CuSO4 testadas, com exceção de 200µM, sendo esta considerada tóxica.
The manipulation of concentration of trace elements in the culture medium represents a good strategy to increase the production of secondary metabolites in tissue culture. This study aimed to demonstrate the influence of copper sulphate in the production of betacyanin and the multiplication of plants of Alternanthera philoxeroides (alligator weed) cultured in vitro. Nodal segments, obtained from plants pre-stablished and after three subcultures, were inoculated in basic MS with different concentrations of CuSO4 (0, 25, 75, 125, 175, 200µM). The results were subjected to analysis of variance, polynomial regression and correlation analysis between the morphological variables and the production of betacyanin. The experimental design was completely randomized with six concentration of CuSO4 and five replicates represented by a bottle containing four explants. Concentrations above 75µM decreased the height of the plant, number of shoots and buds and root growth, while the concentration of 125µM resulted in the highest fresh mass production. Betacyanin production increased 60 percent over control with 175µM CuSO4. Plant growth occurred in all tested concentrations of CuSO4, with the exception of 200µM which was toxic.
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O objetivo do presente trabalho foi otimizar um protocolo de regeneração de explantes cotiledonares de melão, cultivar 'Gaúcho', avaliando a composição de meios de germinação e o tempo de permanência dos explantes nesses meios. Para isso, as sementes foram germinadas em meio MS semi-sólido contendo BAP ou ANA e sem esses reguladores de crescimento. As sementes permaneceram nesses meios por um, dois, três e quatro dias, sendo então seus cotilédones inoculados em meio MS contendo diferentes concentrações de BAP (0,5; 0,9; 1,5 e 2,0mg L-1). As maiores taxas de regeneração ocorreram nos cotilédones oriundos de sementes mantidas durante um e dois dias nos meios contendo 0,5 e 0,9mg L-1 de BAP. O aumento da permanência dos explantes nos meios de germinação e as elevadas concentrações de BAP nos meios de regeneração diminuíram a capacidade organogênica dos explantes e incrementaram a formação de calos.
The aim of the present study was to optimize a cv. Gaucho melon cotyledon explant regeneration protocol, evaluating the germination media composition and the explant exposition period in these media. For this purpose, seeds were germinated in semi-solid MS medium containing either BAP or ANA, and without growth regulators. The seeds were kept in these media for one, two, three or four days; afterwards, their cotyledons were inoculated in MS medium containing different BAP concentrations (0.5; 0.9; 1.5 and 2.0mg L-1). The highest regeneration rates occurred with cotyledons from seeds which had been kept for one or two days in media containing 0.5 and 0.9mg L-1 BAP. Both the increase in the explant exposition time in germination media and high BAP concentrations in regeneration media decreased explant organogenic capacity, and increased callus formation.
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The Plectranthus genus comprises several species generally referred to as boldo, which are highly used in popular medicine due to their anti-dyspeptic, analgesic and digestion-stimulating properties. The amount of natural active principles can vary greatly in the related genotypes, which may lead to the inappropriate use of these plants. This work aimed to analyze the interspecific diversity among four species of the Plectranthus genus (P. grandis, P. barbatus, P. neochilus and P. amboinicus) and the intraspecific diversity of P. barbatus collected from different places in southern Brazil, by means of the RAPD technique. A higher genetic similarity was observed between the P. neochilus and P. amboinicus species (80%), followed by P. grandis and P. barbatus (77%). P. barbatus genotypes from Passo Fundo and Porto Alegre showed a genetic similarity which was close to 100%, while the genetic similarity for P. barbatus genotypes from other locations was higher than 96%. Although a low variability among genotypes of this species was found in this study, RAPD markers allowed a clear differentiation among the analyzed genotypes, showing a 53% mean genetic similarity, with a high correlation value (r = 0.99), which proves a high agreement between the genetic similarity and clustering data.
O gênero Plectranthus abrange plantas de diversas espécies, referidas como boldo, que são utilizadas na medicina popular pelas suas propriedades antidispépticas, analgésicas e estimulantes da digestão. Genótipos relacionados podem diferir amplamente na quantidade de princípios ativos naturais, resultando no uso de plantas não-apropriadas à saúde da população. O objetivo do presente estudo foi avaliar a diversidade genética interespecífica de quatro espécies do gênero Plectranthus (P. grandis, P. barbatus, P. neochilus e P. amboinicus) e intraespecífica de P. barbatus, coletadas em diferentes localidades da região Sul do Brasil, por meio da técnica de RAPD (Random Amplified Polymorphic DNA). Foi observada maior similaridade genética entre as espécies P. neochilus e P. amboinicus (80%), seguido de P. grandis e P. barbatus (77%). Genótipos de P. barbatus provenientes de Passo Fundo e Porto Alegre apresentaram similaridade genética próximo a 100%, enquanto nas demais regiões foi superior a 96%. Embora no presente trabalho tenha sido detectada baixa variabilidade entre genótipos desta espécie, a técnica de RAPD permitiu clara separação entre as quatro espécies analisadas, apresentando uma similaridade genética média de 53%, com um valor de correlação alto (r = 0,99), demonstrando elevada representatividade dos dados de similaridade genética com os de agrupamento.
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Medicina Tradicional , Plantas MedicinaisRESUMO
The aim of the present study was to evaluate the growth and development of apple rootstock shoots submitted to different photon flux densities (7, 14, 21 and 60 µmol m-2 s-1) and three culture media. The best photon flux for maximizing growth, number of shoots and leaves was 14 µmol m-2 s-1, which also resulted in the highest values of chloroplastic pigments. On the other hand, the highest photon flux (60 µmol m-2 s-1) decreased significantly these parameters. Medium with reduced sucrose concentration did not affect the analyzed parameters, enabling an efficient multiplication of the cultivar with only 1 percent of sucrose.
O objetivo do presente estudo foi avaliar características de crescimento e desenvolvimento de brotações de macieira submetidas a diferentes densidades de fluxo de fótons (7, 14, 21 e 60 µmol m-2 s-1) e três meios de cultura. O melhor fluxo de fótons para maximizar o crescimento, número de brotações e de folhas foi de 14 µmol m-2 s-1, o qual também proporcionou os maiores valores de pigmentos cloroplastídicos. Por outro lado, alto fluxo de fótons (60 µmol m-2 s-1) diminuiu significativamente os parâmetros citados acima. O meio com concentração reduzida de sacarose não afetou os parâmetros analisados, possibilitando uma multiplicação eficiente desta cultivar com apenas 1 por cento deste carboidrato.
RESUMO
O objetivo do presente trabalho foi avaliar o efeito do ácido naftalenoacético (ANA) e do carväo ativado no enraizamento in vitro de pereira (Pyrus comunis L.) cv. Carrick. Para tanto, microestacas de pereira com aproximadamente 0,8 a 1cm de comprimento foram utilizadas como explantes. Os tratamentos constituíram-se de três concentraçäo de ANA no meio de cultura (0; 3,2 e 6,4mM) e de duas concentraçäo de carväo ativado (0 e 1 por cento). A partir dos resultados obtidos no experimento, conclui-se que o ANA nas concentraçöes de 3,2 e 6,4mM e na ausência de carväo ativado no meio de cultura, possibilitou um melhor enraizamento de pereira cv. Carrick.