Summary: A modified method for the direct extraction of DNA from alkaline-saline soils with minimum DNA fragmentation and a possible reduction in chimera formation during polymerase chain reaction (PCR) was developed. The commercial extraction kit Power Soil DNA (Mo Bio™ Laboratories, Inc.) was used as a reference technique. The method reported here was based on cell lysis employing ethylenediaminetetraacetic acid (EDTA), sodium dodecyl sulfate (SDS), and cell disruption with mechanical force with FastPrep-24™ equip followed by one cycle of freezing at -40 °C for 60 min and thawing at 65 °C for 20 min. The extraction method was tested for allophonic soils with large concentrations of organic matter, fulvic and humic acids, electrolytic conductivity (EC) ranging between 2.6 dS m-1 and 39.9 dS m-1, and pH between 8.8 and 10.9. The yield of DNA extracted depended on soil type, i.e., DNA extracted from soil varied between 2.35 (Texcoco-2) to 3.66 (Texcoco-1) μg DNA g-1 soil. The proposed method in this study produced enough DNA with yield and quality for PCR amplification of 16S rDNA when bovine serum albumin (BSA) was added to the reaction buffer. The DNA obtained had sufficient quality and yield for later use for 16S sequencing or possible use in other sequencing technologies, e.g. whole metagenome shotgun sequencing.

Resumen: Se desarrolló un método modificado para la lisis bacteriana y la extracción directa de ADN de suelo alcalino-salino con mínima fragmentación y con esto, evitar posiblemente, la formación de quimeras a partir de pequeños fragmentos de ADN durante la amplificación por PCR. Se utilizó el kit Power Soil DNA (Mo Bio™ Laboratories, Inc.) como técnica de referencia. El método reportado se basó en la lisis celular en presencia de dodecilsulfato de sodio (SDS), ácido etilendiaminotetraacético (EDTA) y lisis celular mecánica empleando un equipo Fast-Prep-24™, seguido de un ciclo de congelación a -40 °C durante 60 min y descongelación a 65 °C durante 20 min. El método de extracción se probó para suelos alofónicos con grandes concentraciones de materia orgánica, ácidos fúlvicos y húmicos, conductividad electrolítica (CE) entre 2.6 dS m-1 y 39.9 dS m-1, y pH entre 8.8 y 10.9. La concentración del ADN extraído de los suelos osciló entre 2.35 (Texcoco-2) y 3.66 (Texcoco-1) µg de ADN g-1 de suelo, y el rendimiento dependió del tipo de suelo empleado. El método produjo ADN lo suficientemente puro para la amplificación del gen 16S rADN por PCR cuando se añadió albúmina de suero bovino (BSA) al buffer de reacción. El ADN obtenido presenta suficiente calidad y rendimiento para su uso posterior para la secuenciación del gen 16S rADN, o para un secuenciamiento directo, i.e. secuenciación del metagenoma.

Abstract: Introduction: Halophiles can be found in hypersaline environments and they can synthesize products of industrial interest. Method: In this work, 37 bacterial strains were isolated from the sediment of a dried-out maar of the “Hoya Rincón de Parangueo” (Mexico) on different culture media with 20% NaCl and pH 9, while potential industrial extracellular enzymes were determined. Results: Eight genera Salsuginibacillus, Alkalibacillus, Bacillus, Staphylococcus, Oceanobacillus, Halomonas and Nesterenkonia besides 15 distinct species belonging to Actinobacteria, Firmicutes and Proteobacteria were identified. The L371, LTA7 and SU3 isolates produced proteases, M20, L5, L7, L8, Y1, Y2, M3, M9 and RA lipases, LTA4 and SU3 amylases, while LTA7, Y2, M5, M9 and RA caseinases with enzymatic activity at pH 9. Production of siderophore was found in 17 isolates. Discussion or Conclusion: It is reported for the first experimental evidence of siderophores production by N. alba, Alkalibacillus and Oceanobacillus at 6% NaCl (w/v). Isolates RE, RG1, RG2, RH1, RA and I11 showed 2.8% to 4.1% genetic distance with Nesterenkonia species and might represent new species.

Resumen: Introducción: Los microorganismos halófilos los podemos encontrar en ambientes hipersalinos y pueden sintetizar productos de interés industrial. Método: En el presente trabajo, 37 aislados se obtuvieron del sedimento del maar desecado de la “Hoya Rincón de Parangueo” (México) en diferentes medios de cultivo que contenían 20% de NaCl y pH de 9, se determinó el potencial de producción de enzimas extracelulares de interés industrial por estos aislados. Resultados: Se identificaron ocho géneros bacterianos Salsuginibacillus, Alkalibacillus, Bacillus, Staphylococcus, Oceanobacillus, Halomonas y Nesterenkonia además de 15 especies diferentes de Actinobacteria, Firmicutes y Proteobacteria. Los aislados L371, LTA7 y SU3 produjeron proteasas, M20, L5, L7, L8, Y1, Y2, M3, M9 y RA lipasas, LTA4 y SU3 amilasas y LTA7, Y2, M5, M9 y RA cacesinasas a pH de 9. La producción de sideróforos se encontró en 17 aislados. Discusión o Conclusión: Se reporta la primera evidencia experimental de la producción de sideróforos por N. alba, Alkalibacillus and Oceanobacillu a una concentración de NaCl al 6% (p/v). Los aislados RE, RG1, RH1, RA e I11 tuvieron una distancia genética de 2.8% a 4.1% con especies de Nesterenkonia por lo que pueden representar nuevas especies.

Abstract Yam bean (Pachyrhizus erosus (L.) Urb.) tuber has a low carbohydrate content and contains several aminoacids, but contains few active compounds, such as vitamins and antioxidants. Anthocyanins are antioxidants found in Rubus fructicosus L. The osmotic drying is a technique that can be used to impregnate antioxidants in a matrix, so the objective of this study was to impregnate yam bean tuber slices with anthocyanin. The effect of temperature (40, 50 and 60oC), sucrose content (40, 50 and 60oBrix) and vacuum pulse (0, 300 and 600 mbar) on water loss (WL), solid gain (SG), color changes (ΔΕ) and anthocyanin concentration (ΔA) during osmotic drying of yam bean slices was determined. Polynomial equations were used to determine changes in WL, SG, ΔΕ and ΔA of yam bean slices after 6 h of osmotic drying. An osmotic solution at 60oC with a SC of 40oBrix, applying a vacuum pulse of 12 mbar maximized anthocyanin impregnation (6.67 mg anthocyanin per g initial dry matter) in tuber slices. The Page equation predicted optimum WL, SG and ΔA of yam bean tuber slices during osmotic drying. No relation was found between temperature, sucrose content and vacuum pulse with K and n parameters in the Page equation.

ABSTRACT Among the most serious environmental disasters that threaten biodiversity in soil are oil spills. Different factors control the removal of hydrocarbons from soil, e.g., soil characteristics, composition of the contaminant, and the composition of the microbial population. Toluene is highly volatile, toxic and soluble in water so its removal from soil is important to limit the damage to the environment. Two soils, an arable soil from Otumba, State of Mexico, Mexico, and an alkaline soil from the former Texcoco lakebed, were spiked with three concentrations of toluene (C7H8) and incubated aerobically for 20 days. The CO2 emission and the contaminant in the headspace of the microcosm and the soil were monitored. The CO2 emission increased with increased application of toluene, but showed a lag of two days. After one day, volatilization of toluene was substantial from both soils, 34 % from the Texcoco soil and 58 % from the Otumba soil, but most of it was removed from the headspace within two days. Overall, 98 % of the toluene added to soil was recovered. No abiotic factor affected the removal of toluene from soil. Nearly all toluene was removed from the Texcoco soil within one day independent of the amount applied, but it took more than three days in the arable soil. A lag of two days between dissipation and mineralization was detected, as toluene first has to be incorporated in the microbial cell before it can be degraded. The removal of toluene was faster from the Texcoco soil than from the arable soil.

RESUMEN Entre los desastres ambientales más graves que amenazan a la biodiversidad se encuentran los derrames de hidrocarburos en ríos, mares, océanos y el suelo. Diferentes factores controlan la eliminación de hidrocarburos del suelo, es decir, las propiedades del suelo, las características y composición del contaminante y la composición de la población microbiana. El tolueno es altamente volátil, tóxico y soluble en agua, por lo que su eliminación del suelo es importante para limitar los daños al ambiente. Se utilizaron dos suelos del Estado de México, un suelo agrícola de Otumba y un suelo alcalino del antiguo lecho del lago de Texcoco, los que fueron contaminados con tres concentraciones de tolueno y se incubaron aeróbicamente durante 20 días. Se monitoreó la emisión de CO2 y el contaminante en el espacio poroso del suelo. La emisión de CO2 aumentó cuando la aplicación del tolueno fue mayor, pero esto se observó después de dos días. La volatilización del tolueno fue sustancial en ambos suelos, es decir, 34 % en el suelo de Texcoco y 58 % en el suelo de Otumba, pero la mayor parte del tolueno se removió del espacio poroso en dos días. En general, se recuperó el 98 % del tolueno añadido al suelo. Ningún factor abiótico afectó la eliminación del tolueno del suelo. Casi todo el tolueno se retiró del suelo de Texcoco en un día, independientemente de la cantidad aplicada, pero tardó más de tres días en el agrícola. El tolueno se removió rápidamente del suelo y ningún factor abiótico afectó su concentración. Se observó un retraso de dos días entre la disipación y la mineralización del tolueno, ya que primero tuvo que ser incorporado en la célula microbiana antes de ser degradado. La remoción del tolueno fue más rápida en el suelo de Texcoco que en el suelo agrícola.

The application of organic waste products, such as vinasses, to the soil is a common practice in different countries. Vinasses are a residual liquid generated during various processes such as ethanol production and beverages distillation. However, little is known about how the vinasses affect the content and species distribution of arbuscular mycorrhizal fungi (AMF) in soils irrigated with vinasses. The aim of this research was to determine the presence, spore density and taxonomic identification of AMF to assess in vinasses irrigated (VS) and unirrigated soils (CS). Sixteen species were identified in irrigated and unirrigated soils, with a predominance of Acaulospora mellea, A. scrobiculata, Funneliformis geosporum, F. mosseae and Paraglomus occultum. Only Clareidoglomus etunicatum, Septoglomus constrictum, and Racocetra gregaria were found in VS, while A. morrowiae and Scuttelospora reticulate were only found in CS. The AMF abundance, root colonization, richness and biodiversity indices were not affected by vinasses application. It was found that irrigation of soil with vinasses seemed to have only a limited effect on AMF. To our knowledge, this is the first description of the species of AMF present in soil frequently irrigated with vinasse. This study could serve as a base for further investigations into the effect of vinasse on the soil microbial community and crop yields.

Abstract: Background: Microbial consortia have ecological and biotechnological importance since they contribute to the biogeochemical cycles in nature and produce compounds of high economical value. Goals: Research for this paper involved the polyphasic study of a photosynthetic microbial consortium (MC) in order to identify the microorganisms that comprise it, in addition to exploring the theory of the biotechnological potential of each partner within the consortium. Methods: Study of morphological and phylogenetic diversity. Results: Twenty-one different microorganisms were identified that make up the MC belonging to the phyla Proteobacteria (Rhodobacter sp., Devosia insulae, Pedomicrobium americanum, Alpha proteobacteria, Aquaspirillum delicatum, Methylibium petroleiphilum and Nannocystis sp.), Bacteriodetes (Flavobacterium sp. and Flavobacterium aquatile), Cyanobacteria (Aphanizomenon aphanizomenoides, Leptolyngbya sp. and Anabaena oscillarioides), Chlorophyta (Monoraphidium sp. and Chlorella sp.), Heterokontophyta (Cyclotella meneghiniana, Melosira varians, Cocconeis placentula, Achnanthidium chlidanos, Navicula radiosa, Fragilaria ulna and Nitzschia sp.). This microbial consortium was shown to have a high capacity for nitrogen fixation (10,294 nmol ethylene g-1 dry weight h-1). Conclusions: The identification of microorganisms that form the MC and their capacity for growth and nitrogen fixation in a photobioreactor, give us a glimpse of their possible biotechnological application as a biofertilizer.

Resumen: Antecedentes: Los consorcios microbianos son de importancia ecológica y biotecnológica por que contribuyen a los ciclos biogeoquímicos y producen compuestos de alto valor añadido. Objetivos. Realizar el estudio polifásico de un consorcio microbiano (CM) fotosintético, con el fin de identificar los microorganismos que lo integran, además del aporte teórico del potencial biotecnológico de cada uno de ellos como parte del consorcio. Métodos: Se empleó un estudio de la diversidad morfológica y filogenética. Resultados: En el CM se identificaron 21 microorganismos diferentes pertenecientes a los phyla Proteobacteria (Rhodobacter sp., Devosia insulae, Pedomicrobium americanum, Alpha proteobacteria, Aquaspirillum delicatum, Methylibium petroleiphilum y Nannocystis sp.), Bacteroidetes (Flavobacterium sp. y Flavobacterium aquatile), Cyanobacteria (Aphanizomenon aphanizomenoides, Leptolyngbya sp. y Anabaena oscillarioides), Chlorophyta (Monoraphidium sp., Chlorella sp.), Heterokontophyta (Cyclotella meneghiniana, Melosira varians, Cocconeis placentula, Achnanthidium chlidanos, Navicula radiosa, Fragilaria ulna y Nitzschia sp.). Este consorcio microbiano ha mostrado tener una elevada capacidad de fijación de nitrógeno (10,294 nmoles etileno g-1 peso seco h-1). Conclusiones: La identificación de los microorganismos que conforman el CM, su capacidad de crecimiento y la fijación de nitrógeno en un fotobiorreactor, permiten vislumbrar su posible aplicación biotecnológica como biofertilizante.

Native rhizobia are ideal for use as commercial legume inoculants. The characteristics of the carrier used to store the inoculants are important for the survival and symbiotic potential of the rhizobia. The objective of this study was to investigate the effects of peat (PEAT), perlite sugarcane bagasse (PSB), carboxymethyl cellulose plus starch (CMCS), and yeast extract mannitol supplemented with mannitol (YEMM) on the survival, nodulation potential and N2 fixation capacity of the native strains Sinorhizobium mexicanum ITTG R7T and Rhizobium calliandrae LBP2-1T and of the reference strain Rhizobium etli CFN42T. A factorial design (4 × 3) with four repetitions was used to determine the symbiotic potential of the rhizobial strains. The survival of the strains was higher for PEAT (46% for strain LBP2-1T, 167% for strain CFN42T and 219% for strain ITTG R7T) than for the other carriers after 240 days, except for CFN42T kept on CMCS (225%). All the strains kept on the different carriers effectively nodulated common bean, with the lowest number of nodules found (5 nodules) when CFN42T was kept on CMCS and with the highest number of nodules found (28 nodules) when ITTG R7T was kept on PSB. The nitrogenase activity was the highest for ITTG R7T kept on PEAT (4911 μmol C2H4 per fresh weight nodule h−1); however, no activity was found when the strains were kept on YEMM. Thus, the survival and symbiotic potential of the rhizobia depended on the carrier used to store them.

Agriculture in chinampas or 'floating gardens', is still found on the south of Mexico City, it is a high yield pre-Columbian cultivation system, which has soils enriched with organic matter. The objective of this research was to determine the greenhouse gas (GHG) emissions from a chinampa soil cultivated with amaranth (Amaranthus hypochondriacus L.), maize (Zea mays L.) or uncultivated. The soil was characterized and fluxes of GHG (CO2, N2O and CH4) were monitored for one year. The chinampa soil was alkaline saline with an organic C content that ranged from 21.7 t/ha in the 0-20 cm layer of the soil cultivated with amaranth to 28.4 t/ha in the 20-40 cm layer of the uncultivated soil. The cumulative GHG emissions (kg CO2-equivalents/ha/y) were 395, 376 and 258 for N2O, and 44, 30 and 26 for CH4 in the uncultivated, amaranth cultivated and maize cultivated soil, respectively. No significant effect of cultivated crop or soil characteristics on GHG emissions over one year was found. In general, N2O contributed 91 % and CH4 9 % to the global warming potential of the GHG. The organic C was high and distributed equally over the soil profile, because it is an anthropic soil.

La agricultura en chinampas o "jardines flotantes", todavía la podemos encontrar al sur de la Ciudad de México, este es un sistema de cultivo de alto rendimiento pre-colombino con suelos ricos en materia orgánica. El objetivo de esta investigación fue determinar la emisión de gases de efecto invernadero (GEI) del suelo de chinampas cultivadas con amaranto (Amaranthus hypochondriacus L.), maíz (Zea mays L.) y sin cultivo. Se caracterizó el suelo y se monitorearon los flujos de gases de efecto invernadero (CO2, N2O y CH4) durante un año. El suelo de la chinampa fue salino alcalino con un contenido de C orgánico que varió de 21.7 t/ha en la capa de 0-20 cm del suelo cultivado con amaranto a 28.4 t/ha en la capa de 20-40 cm del suelo sin cultivar. Las emisiones de gases de efecto invernadero acumuladas (kg de CO2 equivalente/ha/año) fueron 395, 376 y 258 para el N2O y 44, 30 y 26 para el CH4, en el suelo sin cultivo, en el cultivado con amaranto y en el cultivado con maíz, respectivamente. No se encontró un efecto significativo del cultivo o de las características del suelo sobre las emisiones de gases de efecto invernadero durante un año. En general, el N2O aportó el 91 % y el CH4 aportó el 9 % del potencial de calentamiento global de los GEI. El C orgánico fue elevado y se distribuye por igual en el perfil del suelo, debido a que es un suelo antrópico.

Background: The application of polycyclic aromatic hydrocarbons (PAHs) will affect the bacterial community structure as some groups will be favoured and others not. An alkaline saline soil with electrolytic conductivity (EC) 56 dS m-1 was spiked with anthracene and acetone while their effect on bacterial community structure was investigated. Results: The percentages of Acidobacteria and Actinobacteria decreased over time, while the percentage of Proteobacteria, mostly Xanthomonadales, increased. The percentage of the phylotypes belonging to the Nocardioides, Rhodococcus and Streptomyces, known degraders of PAHs, was larger in the anthracene-amended soil than in the acetone-amended and unamended soil at day 14. The phylotypes belonging to the genera Sphingomonas, also a known degrader of PAHs, however, was lower. Weighted and unweighted PCoA with UniFrac indicated that phylotypes were similar in the different treatments at day 0, but changed at day 1. After 14 days, phylotypes in the unamended and acetone-amended soil were similar, but different from those in the anthracene-spiked soil. Conclusions: It was found that incubating the soil and contaminating it with anthracene changed the bacterial community structure, but spiking the soil with acetone had little or no effect on the bacterial community structure compared to the unamended soil.

The objective of this study was to investigate the effect of vermicompost, worm-bed leachate (WBL) and Glomus mosseae, an arbuscular mycorrhizal fungi (AMF), on growth of lemongrass (Cymbopogon citratus (DC.) Stapf). A response surface methodology, i.e. a three-level Box Benhen design with three repetitions and three blocks, was applied to optimize biomass production, essential oil yield and its composition. Application rates of Glomus mosseae were 0, 1 or 2 g plant-1, vermicompost 0, 5 or 10 g plant-1 and WBL 0, 10 and 20%. The AMF had no significant effect on the variables tested, but vermicompost had a significant effect on essential oil yield and WBL on essential oil yield, myercene concentration and shoot dry weigh (p < 0.05). It was found that lemongrass fertilized with 2.0 g G. mosseae, 5.0 g vermicompost and 20% worm-bed leachate would yield 0.797% essential oil of which 62.6% was citral.

The tropical legume Acaciella angustissima inoculated with or without Sinorhizobium mexicanum ITTG R7T strain was cultivated in an aluminium (Al) spiked soil to study its tolerance towards this metal. Seedlings of A. angustissima were grown in soil with 0, 2, 4 or 6 mg Al kg-1. The effect of Al and inoculation on growth, nodulation, and nitrogen and tannins content in the plants was monitored. Height and total and dry root weight of plantlets decreased significantly when soil was spiked with Al, but increased when inoculated. Al decreased the number of nodules. Inoculum increased total N and tannin content of the plantlets. It was found that Al reduced the growth of the tropical leguminous N2-fixing shrub A. angustissima, while inoculation with S. mexicanum ITTG R7T stimulated its growth and increased its tannin and N content.

La leguminosa tropical Acaciella angustissima inoculada con o sin la cepa Sinorhizobium mexicanum ITTG R7T fue cultivada en un suelo tratado con (Al) para estudiar la tolerancia a este metal. Las plantas de A. angustissima fueron crecidas en el suelo con 0, 2, 4 y 6 mg de Al kg-1. Se hizo un seguimiento del efecto de Al e inoculación en el crecimiento, la nodulación, el contenido de nitrogeno y el contenido de taninos en las plantas. La altura, el peso seco total y el peso seco de la raíz de las plantas decrementó significativamente cuando el suelo fue tratado con Al, pero incrementó cuando fue inoculado. El Al disminuyó el número de nódulos. El inóculo incrementó el N total y el contenido de taninos de las plantas. En este experimento fue encontrado que el Al reduce el crecimiento de la leguminosa arbustiva tropical fijadora de N2 A. angustissima, mientras la inoculación con S. mexicanum ITTG R7T estimula el crecimiento e incrementa el contenido de taninos y nitrógeno.

A região semiárida de Chiapas é dominada por árvores fixadoras de N2 do tipo Acacia angustissima. Foram analisadas amostras de solos daquela região cultivados com milho, as quais foram coletadas em zonas sob cobertura e em regiões não cobertas por A. angustissima em diversas épocas do ano, às quais foi adicionada ureia. As emissões de N2O e CO2 foram monitoradas. A finalidade deste trabalho foi determinar o efeito da uréia, nas épocas secas e de chuvas, sobre as emissões de gases dos solos semiáridos, em condições de laboratório. O solo e a ureia não tiveram efeito na produção de CO2. As emissões de NO2 foram três vezes maiores no solo recolhido na época seca do que no solo recolhido na época úmida, e a adição de ureia duplicou essas emissões. O solo sob a cobertura de A. angustissima apresentou emissões de NO2 duas vezes superiores às do solo arável, porém 1,2 vez inferior à de solo colhido em zonas não cobertas por A. angustissima. Essas emissões foram cinco vezes maiores em solos incubados a 40 % da capacidade de retenção de água (CRA) do que em solo úmido, mas 15 vezes mais baixas do que em solo incubado a 100 % CRA. Foi perceptível que a época de amostragem e o teor em água do solo tiveram efeito nas emissões de NO2, enquanto o uso de fertilizantes nitrogenados e o local de amostragem tiveram efeito menor.

The semi-arid region of Chiapas is dominated by N2 -fixing shrubs, e.g., Acacia angustissima. Urea-fertilized soil samples under maize were collected from areas covered and uncovered by A. angustissima in different seasons and N2O and CO2 emissions were monitored. The objective of this study was to determine the effects of urea and of the rainy and dry season on gas emissions from semi-arid soil under laboratory conditions. Urea and soil use had no effect on CO2 production. Nitrons oxide emission from soil was three times higher in the dry than in the rainy season, while urea fertilization doubled emissions. Emissions were twice as high from soil sampled under A. angustissima canopy than from arable land, but 1.2 lower than from soil sampled outside the canopy, and five times higher from soil incubated at 40 % of the water-holding capacity (WHC) than at soil moisture content, but 15 times lower than from soil incubated at 100 WHC. It was found that the soil sampling time and water content had a significant effect on N2O emissions, while N fertilizer and sampling location were less influent.

A response surface technique was used to analyze the effect of Glomus fasciculatum, Pseudomonas fluorescens and worm-bed leachate (WBL) on growth, yield and characteristics of tomato (Lycopersicon esculentum Mill). The treatments combined inoculation with or without P. fluorescensor G. fasciculatum and the application of WBL at 20% (v/v) each day or every three days. Plant height, number of leaves and yield of tomato fruits was not affected by the factors studied. However, plants with foliar application of WBL each day developed wider stems than those with an application every three days. The pH of the fruits was lower when WBL was applied every three days compared to a daily application. The soluble solids content of the fruits was higher when WBL was applied daily compared to those sprayed every three days. Plant development was not affected by addition of P. fluorescens, G. fasciculatum or WBL, but WBL changed fruit characteristics.

An in vitro culture procedure was developed to induce shoots and roots of Guarianthe skinneri (Orchidaceae) plantlets regenerated from seed-derived protocorms on a Murashige and Skoog (MS) médium supplemented with 6-benzyladenine (BA), indole-3-acetic acid (IAA), a-naftalenacetic acid (NAA) and gibberellic acid (GA3). A máximum of 10.6 shoots was obtained with 16.1 μM NAA, 17.1 μM IAA, 6.3 x 10-9 μM GA3 and 0.0023 μM BA. A máximum of 4.0 roots on each shoot with 5.4 μM NAA, 17.1 μM IAA, 0.001 μM AG3 and 4.6 x 10-9 μM BA. Máximum shoot and root length was obtained with a minimum of GA3, but a máximum IAA. GA3, was the main factor controlling shoot and root induction and elongation.

Se desarrolló un procedimiento para el cultivo in vitro para inducir brotes y raíces en las plántulas de Guarianthe skinneri (Orchidaceae) regeneradas a partir de protocormos derivados de semillas en un medio de Murashige & Skoog (MS) complementado con 6-benziladenina (BA), ácido indol-3-acético (AIA), ácido a-naftalenacético (ANA) y ácido giberélico (GA3). Se obtuvo un máximo de 10,6 brotes con 16,1 μM de ANA, 17,1 μM de AIA, 6,3 x 10-9 μM de GA3 y 0,0023 μM de BA. Un máximo de 4,0 raíces en cada brote se obtuvo con 5,4 μM de ANA, 17,1 μM de AIA, 0,001 μM de AG3 y 4,6 x 10-9 μM de BA. La longitud máxima de brotes y raíces se obtuvo con la más baia concentración de GA3, y la mayor concentración de AIA. El GA3, fue el factor principal que controló la inducción y la elongación de los brotes y raíces.