Eugenia Jacira Bolacel Braga

Composição do óleo essencial de quatro espécies do gênero Plectranthus

Palavras-chave: plantas medicinais, boldo, hidrodestilacao, CG-MS, GC-FID ABSTRACT: Essential oil composition of four Plectranthus species. Plectranthus has been considered one of the richest genera in essential oils within the Lamiaceae family, which includes several species with medicinal properties. Some of them are commonly known as boldo and present taxonomic similarities and several synonymies, with antidyspeptic, analgesic and digestive actions. The aim of this study was to evaluate quantitatively and qualitatively the essential oils from P. amboinicus, P. barbatus, P. grandis and P. neochilus leaves. The oil was extracted by hydrodistillation using pentane as extracting solvent and was repeated three times for each species. The analysis of essential oil components by GC/MS in the four Plectranthus species identified 14 chemical components, mostly sesquiterpenes. High concentration of trans-caryophyllene was found in the studied oils. Some chemical components were specific for each species and other components had common occurrence in all four species, allowing their differentiation into two groups, one composed of P. amboinicus and P. neochilus and another one by P. grandis and P. barbatus. In conclusion, the four boldo species had significant differences as to essential oil yield and chemical composition.

Waterlogging-induced changes in fermentative metabolism in roots and nodules of soybean genotypes

Waterlogging blocks the oxygen supply to the root system which inhibits respiration, and greatly reduces the energy status of cells that affect important metabolic processes. This study evaluated fermentative metabolism and carbohydrate contents in the root system of two soybean (Glycine max L. Merril) genotypes under hypoxic and post-hypoxic conditions. Nodulated plants (genotypes Fundacep 53 RR and BRS Macota) were grown in vermiculite and transferred to a hydroponic system at the reproductive stage. The root system was submitted to hypoxia by flowing N2 (nitrogen) gas in a solution for 24 and 72 h. For recovery, plants returned to normoxia condition by transfer to vermiculite for 24 and 72 h. Fermentative enzyme activity, levels of anaerobic metabolites and carbohydrate content were all quantified in roots and nodules. The activity of alcohol dehydrogenase, pyruvate decarboxylase and lactate dehydrogenase enzymes, as well as the content of ethanol and lactate, increased with hypoxia in roots and nodules, and subsequently returned to pre-hypoxic levels in the recovery phase in both genotypes. Pyruvate content increased in nodules and decreased in roots. Sugar and sucrose levels increased in roots and decreased in nodules under hypoxia in both genotypes. Fundacep RR 53 was more responsive to the metabolic effects caused by hypoxia and post-hypoxia than BRS Macota, and it is likely that these characteristics contribute positively to improving adaptation to oxygen deficiency.

Light quality on the in vitro growth and production of pigments in the genus Alternanthera

In tissue culture, several chemical and physiological factors can influence the production of secondary metabolites. The growth response and increased secondary metabolite production generated by a high irradiance environment, can be used to determine a favorable habitat for the growth and conservation of medicinal plants. Thus, the present study aimed to evaluate the influence of light quality on growth and production of secondary metabolites in Alternanthera sessilis (L.) R. Br. ex DC. (sessile joyweed), Alternanthera philoxeroides (Mart.) Grisebach (alligatorweed), Alternanthera tenella Colla (joyweed), and Alternanthera brasiliana (L.) Kuntze (Brazilian joyweed) plants cultured in vitro. The species were grown in MS medium, for 45 days in different light qualities (blue, white, and red). Growth parameters and biochemical analysis were performed at the end of the study. The results show that the red light allowed a higher accumulation of biomass in most species; red and white light were great inductors for the production of betacyanin and the blue light favored the enhancement of flavonoids. In this manner, the quality of light can affect the betacyanin, betaxanthin, and flavonoid biosynthesis as well as growth patterns in the related Alternanthera species. Based on the data presented, we suggest that specific genes can encode the pigment production according to the light quality which exhibit distinct activation patterns in different plant species.

Development of rice seedlings grown from pre-hydrated seeds and irradiated with gamma rays

Tecnicas como radiacoes ionizantes, utilizadas para induzir mutacoes constituem ferramenta eficaz no aumento de variabilidade genetica em programas de melhoramento de especies de interesse economico. Neste trabalho, objetivou-se verificar o efeito de diferentes doses de radiacao gama Co60 em sementes previamente embebidas sobre a emergencia e o crescimento inicial de plântulas de duas cultivares de arroz. Lotes de sementes com 25% de umidade das cultivares BRS Querencia 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 vegetacao. Os resultados mostraram que a radiacao gama afetou o desenvolvimento das plântulas, sendo que a maior dose testada (200 Gy) reduziu, significativamente, a emergencia e o indice de velocidade de emergencia. Os parâmetros de crescimento apresentaram maior reducao na cv. BRS Querencia. Na atividade das enzimas antioxidantes, a superoxido dismutase expressou pouca variacao para os periodos avaliados. Ja, 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 radiacao gama.

Produção de betacianina em erva-de-jacaré cultivada in vitro com diferentes concentrações de sulfato de cobre

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% over control with 175µM CuSO4. Plant growth occurred in all tested concentrations of CuSO4, with the exception of 200µM which was toxic.

Análise multivariada da divergência genética de genótipos de arroz sob estresse salino durante a fase vegetativa

Soil salinity is a limiting factor for rice cultivation, especially in the early stages of development and the flowering period. The use of sources of poor quality water for irrigation results in the accumulation of salts in the soil, causing major toxicity in culture. A solution to the problem would be the introduction of varieties with tolerance to high salinity. Hus the aim of this work is to evaluate genetic divergence among rice genotypes, aiming at the selection of genotypes tolerant to salinity during the vegetative phase. Seeds of 10 rice genotypes were grown in vitro on MS medium supplemented with 0 and 136 mM NaCl. After 21 days, six morphological characters were evaluated and the results subjected to multivariate analysis. The methods of Tocher, based on Mahalanobis distance, and graphic dispersion of canonic variables followed the same pattern of clustering structure, forming six groups. The characteristic of shoot fresh weight was the largest contributor to the genetic dissimilarity between genotypes by the method of Singh, while the other two canonic variables were sufficient to account for 91.27% of observed variation. Under the experimental conditions tested, the genotypes showed different degrees of salinity tolerance, while Colossus BRS, BRS Bojuru and BR IRGA 410, belonging to the groups three and four, were those who were more tolerant genotype and Moti, belonging to two what was more sensitive to salt stress.

Enraizamento in vitro de pereira (Pyrus communis L.) cv. Carrick

The aim of the present work was to evaluate the effects of naphthaleneacetic acid (NAA) and activated charcoal on the in vitro rooting of the pear tree (Pyrus communis L.) cv. Carrick. Therefore pear tree microshoots with approximately 0.8 to 1cm of length were used as explant. The treatments were constituted of three concentration of NAA in the culture medium (0; 3.2 and 6.4mM) and two concentration of activated charcoal (0 and 1%). NAA in the concentration of 3.2 and 6.4mM and in the absence of activated charcoal in the culture medium, showed better rooting rate to pear tree cv. Carrick.

Evaluation of stability and validation of reference genes for RT-qPCR expression studies in rice plants under water deficit

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 (β-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 β-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.

Rooting and acclimatization of the Japanese plum tree, cv. América

Rooting and acclimatization are limiting steps in plant micropropagation, especially in woody plant species. This study aimed to evaluate the IAA and IBA effect on the in vitro rooting and acclimatization of micropropagated shoots of Japanese plum (Prunus salicina Lindl.) cv. America. Shoots from 3 to 4 cm long were inoculated in MS medium with half salt and vitamin concentrations (MS/2) added with IAA and IBA (0, 0.25, 0.5, 0.75 and 1 mg L-1). After a 20-day period in in vitro cultivation, the shoots were evaluated, and then transferred to a greenhouse, and evaluated after 30 days. At the end of the in vitro cultivation period, no significant interactions were observed for number of roots per shoot and rooting percentage, but a significant effect was recorded for auxin type only, for which shoots grown in media added with IBA showed high values - 0.87 and 41.95%, respectively. A linear increase response from 1.45 to 5.75 cm was verified for root length of shoots cultivated in IBA medium; however, no significant effect was observed, and a 0.86 cm average root length per shoot grown in medium added with IAA was found. After 30 days of acclimatization period, the largest survival percentage was obtained from shoots cultivated in medium with 1 mg L-1 of IBA and IAA (88% and 92%, respectively). Although, IBA provided the highest in vitro rooting, most of the surviving shoots were those originated in IAA-added medium, probably because IBA promoted longer fibrous roots, less appropriate for transplant and soil fixation, as they are easily damaged. It was concluded that in vitro rooting with the addition of the highest IAA concentration (1 mg L-1) provided the greatest plant survival during the acclimatization period of the Japanese plum cv. America.

Diversidade genética entre acessos de espinheira-santa (Maytenus ilicifolia Mart. ex Reis.) coletados no estado do Rio Grande do Sul, Brasil

Maytenus ilicifolia Mart. ex Reis., popularmente conhecida como espinheira-santa, e especie autoctone pertencente a familia Celastraceae, usada para tratamento de ulceras gastricas e gastrites. Devido a importância medicinal, houve aumento no extrativismo das populacoes naturais, tornando-a uma especie prioritaria para a conservacao, a fim de evitar a erosao genetica. Buscou-se com este trabalho analisar a diversidade genetica de 20 acessos de M. ilicifolia coletados em diferentes localidades no Rio Grande do Sul. Utilizando marcadores moleculares do tipo AFLP, foram testadas oito combinacoes de primers, que geraram 455 bandas eletroforeticas, 100% polimorficas. As combinacoes de primers E-ACC/M-CAA, E-ACG/M-CTA, E-ACG/M-CTC apresentaram o maior numero de bandas eletroforeticas, 71 cada, totalizando 46,80% do polimorfismo total. Os valores de similaridade genetica calculada pelo coeficiente simple matching foram utilizados para gerar o dendrograma de similaridade pelo metodo UPGMA. Foi obtido alto coeficiente de correlacao cofenetica (r=0,94), demonstrando elevada representatividade dos dados de similaridade genetica no dendrograma. Pela AMOVA verificou-se que 89,33% da diversidade total ocorreram entre individuos dentro das populacoes. A caracterizacao molecular de acessos de Maytenus ilicifolia por meio de AFLP foi eficiente para identificar diversidade genetica. Atraves da analise de similaridade genetica o banco de germoplasma poderia ser composto com os acessos que apresentaram menor similaridade e maior numero de alelos, permitindo com que estes fornecessem ampla cobertura do genoma que compoem Maytenus ilicifolia. Os acessos que ficaram agrupados em mesmo cluster e com numero reduzido de alelos podem ser descartados deste banco. A diversidade genetica intrapopulacional identificada por esse marcador foi muito maior do que aquela entre populacoes.