Influence of colorful light-emitting diodes on growth, biochemistry, and production of volatile organic compounds in vitro of Lippia filifolia (Verbenaceae).

Lippia filifolia Mart. & Schauer belongs to the Verbenaceae family and it is endemic from the rupestrian fields of the Espinhaço mountain range, located in Minas Gerais, Brazil. It is an aromatic species with medicinal potential due to the production of volatile compounds that constitute its essential oil. The objective of this work was to evaluate the effects of light quality using light-emitting diodes (LEDs) over the growth of L. filifolia grown in vitro after 45 days of culture, analyzing its volatile organic compounds (VOCs), biochemical, and biometric traits. This study had four treatments according to the wavelength of LED lamps: (i) white (control), (ii) blue, (iii) red, and (iv) a combination of red + blue (mix). The light quality influenced the growth, metabolism, and VOCs production of plantlets. The specimens showed higher height under red and white treatments and higher biomass accumulation, nodal segments, and shoot numbers under the mix treatment. Higher total carbohydrate content was also observed on the mix treatment, while the white LED provided higher chlorophylls and carotenoids contents. In addition, the lipid peroxidation was more pronounced in mix and white LEDs treatments, and it was also observed significant but not quite changes in VOCs profiles due to light quality. Eucalyptol was the compound found in a higher concentration among the VOCs of L. filifolia grown in vitro at all light quality treatments studied.

Study of the influence of wavelengths and intensities of LEDs on the growth, photosynthetic pigment, and volatile compounds production of Lippia rotundifolia Cham in vitro.

Lippia rotundifolia Cham. is in the family Verbenaceae and is endemic to the Cerrado. This species is aromatic and characterized by the presence of glandular trichomes on its leaves that are rich in monoterpenes. The objective of this study was to evaluate the growth, photosynthetic pigment production, and chemical composition of L. rotundifolia grown in vitro under different light wavelengths and intensities. The light intensities consisted of five treatments using cool white fluorescent lamps at 20, 54, 78, 88, and 110 µmol m-2 s-1. The light quality consisted of six treatments using light-emitting diodes (LEDs) in different light wavelengths, namely, white, red, blue, and their interactions: 1R:1B, 2.5R:1B, and 1R:2.5B. After 45 days, the biometric parameters, photosynthetic pigment content, and volatile compounds were evaluated. The lower light intensities of 20 and 54 µmol m-2 s-1 generated higher growth, photosynthetic pigment content, and biomass accumulation. Myrcene and pentadecane were highest under light intensities of 88 and 110 µmol m-2 s-1, respectively. The highest limonene and ocimenone levels were obtained at 20 and 54 µmol m-2 s-1 intensity, respectively, and the highest myrcenone content was obtained at 78 µmol m-2 s-1 intensity. Regarding the light wavelengths, the combination of red and blue spectra further stimulated plantlet growth, and the 2.5R:1B combination obtained the best biometric data and total chlorophyll content. The z-ocimenone chemical compound contents were highest under the 1R:2.5B light spectrum. The monochromatic blue spectrum increased the myrcene and limonene content but decreased the myrcenone content, which was increased by red light. The highest pentadecane contents were obtained with the white spectrum and the red and blue combinations.

Ecophysiological response of Lippia gracilis (Verbanaceae) to duration of salt stress.

The objective of this work was to investigate the effects of salinized water on Lippia gracilis by determining the ion accumulation capacity and morphophysiological changes as a function of salinity and time of exposure to stress. L. gracilis was irrigated with water containing different concentrations of salts and electrical conductivities. The analyses were conducted 25 and 50 days after stress (DAS), in leaf, stem/branches, and roots. Plant height (Hplants), basal stem diameter (Φstem), and mean unitary leaf area (ULA) were determined. After that, the plant material was dried, and the total dry biomass (TDB) (in g plant-1), leaf dry biomass (LDB), stem dry biomass (SDB), and the roots dry biomass (RDB) were determined. Based on these data, the following variables were calculated: total leaf area (TLA) in cm2 plant-1; biomass allocation fraction (BAF) obtained by dividing the biomass of the stem, leaves, and roots, separately, with the total plant biomass; relative growth rate (RGR); net assimilation rate (NAR); leaf area ratio (LAR); specific leaf area (SLA); and sclerophylly index (SI). The concentrations of potassium and sodium ions were quantified by atomic absorption spectrophotometry and the chloride ion concentration was determined by argentometric titration. L. gracilis showed a variable response to salt stress as a function of time, having a considerable capacity to withstand an increasing load of toxic ions, while maintaining a positive growth rate, highlighting the potential use of the species in moderately saline environments.

Tipo de estaca e substrato na propagação vegetativa de Lippia gracilis Schauer / Cutting type and substrate on vegetative propagation of Lippia gracilis Schauer

Lippia gracilis é uma planta nativa da Caatinga, rica em óleo essencial com atividade antimicrobiana. O trabalho objetivou avaliar o efeito de diferentes tipos de estacas e substratos na propagação vegetativa de L. gracilis . O experimento foi montado em delineamento inteiramente casualizado, em esquema fatorial 3 x 3, sendo 3 tipos de estacas (apical, mediana e basal) e 3 tipos de substratos (areia + húmus, argila + húmus e areia + argila + húmus), com 5 repetições cada. Aos 40 dias foram avaliadas: porcentagem de estacas brotadas e enraizadas, número médio de brotos, comprimento da maior raiz e biomassa seca dos brotos e raízes. Em todas as variáveis as estacas medianas e basais apresentaram melhores resultados do que as apicais. O substrato influenciou apenas na biomassa seca dos brotos, sendo o composto de argila + húmus superior ao areia + argila + húmus e igual, em significância, ao areia+ húmus.(AU)

Lippia gracilis is a native plant of the Caatinga, it is rich in essential oil with antimicrobial activity. The study aimed to evaluate the effect of different types of cuttings and substrates on vegetative propagation of L. gracilis. The experimental design was completely randomized, in factorial scheme 3 x 3, with 3 types of cuttings (apical, median and basal) and 3 substrates (sand + humus, clay + humus and sand + clay + humus), with 5 replications each. After 40 days were evaluated: percentage of sprouted cuttings and rooted, average number of shoots, length of roots and dry biomass of shoots and roots. In all variables the middle and basal cuttings showed better results than the apical. The substrate influenced only in the dry biomass of shoots. The substrate composed of clay + humus was better than the sand + clay + humus and equal in significance to the sand + humus.(AU)

Estabelecimento in vitro e aclimatização de Lippia alba (Mill. ) N. E. Brown / In vitro establishment and acclimatization of Lippia alba (Mill. ) N. E. Brown

O presente trabalho teve por objetivo estabelecer in vitro a espécie Lippia alba (Mill.) N. E. Brown e promover a aclimatização de mudas dessa espécie. Para isso, foi testada a influência de diferentes concentrações e tempos de imersão em hipoclorito de sódio na assepsia dos explantes. Segmentos nodais foram imersos em hipoclorito de sódio nas concentrações 0,4; 0,6; 0,8 e 1,0 % e nos tempos 8, 12 e 16 minutos. Após 30 dias avaliou-se a contaminação bacteriana (%), número de brotos, número de folhas, e a taxa de sobrevivência (%). A concentração de 1% de hipoclorito de sódio foi a mais eficiente no controle da contaminação. Ápices caulinares de L. alba foram estabelecidos in vitro em meio MS suplementado com diferentes doses de BAP (0; 0,5; 1,0; 1,5 mg L-1). Após 140 dias avaliou-se a contaminação (%), a taxa de sobrevivência (%), a oxidação (%) e o número de brotos. Os melhores resultados foram obtidos para a dose 1,5 mg L-1 deste regulador. Para a aclimatização foram testados quatro tipos de substratos: pó de coco + calcário (1 g L-1), Plantmax® + calcário (1 g L-1), vermiculita + calcário (1 g L-1) e pó de coco + Plantmax® + vermiculita (1:1:1) + calcário (1 g L-1). Avaliou-se a taxa de sobrevivência (%), comprimento da parte aérea (cm), comprimento da raiz (cm), massa fresca da parte aérea e da raiz (g), e a massa seca da parte aérea e da raiz (g). Os melhores resultados foram obtidos quando com o substrato comercial Plantmax®.

The present study aimed to establish the species Lippia alba (Mill.) N. E. Brown in vitro and promote the acclimatization of the seedlings of this species. Therefore, we tested the effect of different concentrations and immersiog times in sodium hypochloritetfor the disinfection of explants. Nodal segments were immersed in sodium hypochlorite at the different concentrations of ,.4; ,.6; ,.8 and ,.0% during the different times of 8, 12 and 16 minutes. After 30 days, bacterial contamination (%), number of shoots, number of leaves and survival rate (%) were evaluated. The 1% concentration of sodium hypochlorite was more effective in controlling contamination. Shoot apices of L. alba were established in vitro on MS medium supplemented with different concentrations of BAP (;, ,.5; ,.0; ,.5 mg L-1). After 140 days, we evaluated the contamination (%), survival rate (%), oxidation (%) and number of shoots. The best results were obtained when we used the dose of ,.5 mg L-1 of this regulator. For acclimatization, we tested four types of substrates: coconut powder + lime (1 g L-1), Plantmax® + lime (1 g L-1), vermiculite + lime (1 g L-1) and coconut powder + Plantmax® + vermiculite (1:1:1) + lime (1 g L-1). We evaluated the survival rate (%), shoot length (cm), root length (cm), fresh weight of shoot and root (g) and dry weight of shoot and root (g). The best results were obtained when using the substrate Plantmax®.

TNT removal from culture media by three commonly available wild plants growing in the Caribbean.

Plants growing in the Caribbean, Rubia tinctorum, Lippia dulcis and Spermacoce remota, were used in vitro to remove TNT from culture media. Plants were found to be resistant to high TNT levels. S. remota was able to remove TNT in less than 48 h. Part of the TNT was physically removed from the culture media by evaporation.

Estabelecimento de protocolo para micropropagação de Lippia gracilis Schauer / Establishment of protocol for Lippia gracilis Schauer micropropagation

A espécie Lippia gracilis SCHAUER (Verbenaceae) é nativa do Nordeste brasileiro e se destaca pela capacidade de acumular nos tricomas glandulares óleos essenciais com atividade antimicrobiana. Tendo em vista que não constam trabalhos na literatura sobre o estabelecimento in vitro dessa espécie, este trabalho teve como objetivo estabelecer protocolo para micropropagação de L. gracilis. Para tanto, ramos contendo folhas foram coletados de plantas matrizes no habitat natural para a confecção de estacas. Em laboratório, os explantes provenientes do processo de estaquia foram assepticamente tratados e inoculados em meio MS, acrescido de fitorreguladores, com o intuito de se estabelecer a melhor dose para o desenvolvimento dos explantes. Em decorrência de altos níveis de contaminação, avaliou-se o efeito da cefalexina. No entanto, apesar do antibiótico ter apresentado diminuição na contaminação bacteriana, a porcentagem de oxidação foi elevada. Portanto, testou-se o carvão ativado, ácido ascórbico, ácido cítrico e metade dos sais de MS quanto a eficiência no controle da oxidação. Concluiu-se que, o antibiótico na concentração utilizada provocou a oxidação dos explantes e os fitorreguladores, bem como os métodos antioxidantes testados, não apresentaram resultados consistentes para o melhor desenvolvimento dos explantes e controle da oxidação, respectivamente.

The species Lippia gracilis Schauer (Verbenaceae) is native to Northeastern Brazil and has been important for its ability to accumulate essential oils with antimicrobial activity in the glandular trichomes. Since there are no reports in the literature on the micropropagation of this species, the present work aimed to establish a protocol for L. gracilis micropropagation. Thus, branches containing leaves were collected from plant matrices in their natural habitat to prepare cuttings. In the laboratory, explants from cutting were aseptically treated and inoculated onto MS medium plus plant growth regulators in order to establish the best dose for the development of explants. Due to high levels of contamination, the effect of cephalexin was evaluated. Although the antibiotic decreased the bacterial contamination, the percentage of oxidation was high. Then, activated charcoal, ascorbic acid, citric acid and half the salts of MS were tested for their effectiveness to control oxidation. In conclusion, the used antibiotic concentration resulted in oxidation of explants. Furthermore, plant growth regulators and antioxidant methods did not show consistent results for a better development of explants and control of oxidation, respectively.

The essential oil of Lippia alba: analysis of samples from French overseas departments and review of previous works.

This paper contains new data on the chemical composition of the essential oil of Lippia alba (Mill.) N. E. Brown, as well as an overview of the available literature. Although the composition of the essential oil of this species is well-documented, discrepancies between the reported results suggest that many chemotypes and morphotypes exist. The analysis of essential oils obtained from the leaves of samples from three different locations in the French Overseas Departments (French Guiana, Martinique, and two different places in Guadeloupe) have shown that the composition of each one is quite different. This new data, along with a review and discussion of published studies, enabled us to establish seven distinct chemotypes. Possible connections between these chemotypes and morphotypes already described were also investigated.