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Browning is a limiting factor for the successful propagation of several, mainly woody, plant species through tissue culture. Bamboos are not exempt from this constraint, which has been described as particularly critical for the micropropagation of several Bambusa species, such as B. lako. To understand the browning process in this species, we investigated whether the browning of in vitro nodal explants was linked to the accumulation of phenolic compounds, polyphenol oxidase activity, and oxidative stress as indicated by the presence of malondialdehyde. A four-point Browning Gradient Index was developed to evaluate these biochemical parameters. We observed an increase in the concentration of total phenolics, polyphenol oxidase activity, and malondialdehyde levels between green and fully brown grades. Histological analysis revealed a greater accumulation of protein in the green shoots compared to brown tissues. Polyphenols and peroxidase were localized in the vascular bundles in all browning grades.

Due to elevated potential associated with the extremely vast compositional space of high-entropy alloys (HEAs), there is a significant drive to explore these alloys in high-performance contexts such as intensive wear and oxidative environments. In this regard, this review article comprehensively explores the utilization of HEAs in cemented carbides, focusing on their role as binders in cermets. The wear resistance and oxidation behavior of HEA-containing cermets depends on the ceramic-binder thermodynamic compatibility, phase transformations during sintering, microstructure, and mechanical properties. Hence, much high quality research has been focused into exploring the combination of several HEAs with tungsten carbide, titanium carbides, nitrides, carbonitrides and diborides along with other ceramic compounds. As there are many HEA-ceramic combinations, this review aims to provide a landscape of the developments in this field, providing detailed information about the chemical compositions, sintering techniques, mechanical properties and wear and oxidation resistance obtained. Finally, the need for further research to fully understand the complex interactions between composition, microstructure, and wear and oxidation resistance is highlighted, aiming to tailor HEA compositions for optimized performance. The findings presented in this review contribute valuable insights into the promising applications of HEAs in cemented carbides.

In the coffee industry, approximately 60% of coffee fruit components are discarded after harvest, posing potential environmental challenges. To repurpose these organic by-products for human consumption, fresh coffee husks from wet coffee processing at a plantation in Tres Ríos, Cartago, Costa Rica, were used to prepare fruit spreads. Three formulations were developed, plain coffee pulp, coffee pulp with pectin, and coffee pulp with guava, each in high- and low-sugar versions (1:1 and 3:1 fruit-to-sugar ratio, respectively). The stability (moisture content, water activity, Brix, and pH), and key nutritional values (sugar profile, minerals, dietary fiber, and fat content) of these spreads were evaluated. Secondary plant metabolites, such as caffeine and tannins, and color were also analyzed. In addition, consumer acceptability was assessed using a hedonic test of the three formulations. The results showed that the high-sugar versions met stability requirements better than the low-sugar ones. Furthermore, both sugar variants had high mineral and dietary fiber contents, qualifying them for the “source of fiber” label according to European Union Food Regulation No. 1924/2006. Caffeine content was within safe limits for adult consumption at 60 mg per 20 g serving, with minimal tannin content (

The coffee supply chain generates over 10 million tons of waste annually, with 70% comprising the fruit pulp and skin. This study investigates using coffee cherry flour from fresh coffee husk as an alternative ingredient in pastries with baking powder and baker’s yeast. We characterized the nutritional and physicochemical properties of this flour, developed high-fiber recipes, and evaluated the effects of substituting wheat flour with varying proportions of coffee cherry flour in plain cakes and sweet yeast breads. We found that coffee cherry flour reduced yeast dough volume increase and pastry specific volume in the coffee cherry flour pastries but enriched them with higher mineral and dietary fiber content compared to the wheat flour pastries.

The alcohol-insoluble residue in Vanilla dressleri, V. odorata, V. planifolia and V. pompona mature leaves was fractionated into water-, oxalate-, HCl- and NaOH-soluble pectins, hemicellulose and lignocellulose. Neutral sugars and uronic acids of each fraction were determined by high-performance anion exchange chromatography-pulsed amperometric detection. V. dressleri differentiated from the other three species based on the higher amounts of the HCl-soluble pectin fraction and the amount of glucose exceeding 5–7 times the values found in the NaOH-soluble pectin fraction in the other species, as well as a cellulose/hemicellulose ratio of ca. 2/3. Analogously, V. planifolia could also be distinguished by its higher cellulose/hemicellulose ratio of ca. 7. In addition to taxonomical implications, these results might be instrumental for defining adequate conditions for cell wall digestion aiming at protoplast isolation and appropriate media composition for cell wall regeneration during protoplast culture, which has been elusive in the Orchidaceae.

In this work, we report a successful protocol to obtain in vitro peach palm (Bactris gasipaes Kunth) “Diamantes 10” plants through somatic embryogenesis from transverse thin cell layer (TCL) explants, dissected from three sections (basal, medial, and apical) of lateral offshoots of adult plants cultured on different concentrations of 4-amino-3,5,6-trichloropicolonic acid (picloram). After swelling and development of primary callus in all treatments, without any strong effect of explant origin or picloram concentration, it was possible to observe the formation of embryogenic structures and the exact point from where they developed. Browning was also observed and correlated to the induction treatments, although it was not an impairment for the production of embryogenic structures. Subsequent maturation and conversion of somatic embryos into plantlets allowed their acclimatization 17 months after culture initiation (ACI), which was quicker than previous reports with juvenile tissues (from embryos or seed-germinated plantlets). To the best of our knowledge, this is the first report on peach palm regeneration through somatic embryogenesis from TCL explants from adult plants and could constitute, after fine-tuning the acclimatization stage, a tool for mass clonal propagation of elite genotypes of this open-pollinated crop, as well as for the establishment of conservation strategies of in situ gene bank plant accessions endangered due to aging and other threats.

El neotrópico es sitio de origen de gran variedad de plantas que actualmente son cultivadas con éxito en diferentes regiones del mundo. Sin embargo, condiciones climáticas adversas, que se pueden ver acrecentadas por efectos del cambio climático antropogénico, pueden afectar su rendimiento y productividad debido a las situaciones de estrés abiótico que se pueden generar. Como alternativa para contrarrestar estos efectos, se ha experimentado con modificaciones genéticas, particularmente en genes relacionados con la producción de osmolitos y factores de transcripción que han llevado a que estas plantas, a nivel experimental, tengan mayor tolerancia a estrés oxidativo, altas y bajas temperaturas y fotoinhibición, sequía y salinidad, mediante la acumulación de osmoprotectores, la regulación en la expresión de genes y cambios en el fenotipo. En este trabajo se presentan y describen las estrategias metodológicas planteadas con estos fines y se complementan con ejemplos de trabajos realizados en cultivos de origen neotropical de importancia económica, como maíz, algodón, papa y tomate. Además, y debido a la novedad y potencial que ofrece la edición génica por medio del sistema CRISPR/Cas9, también se mencionan trabajos realizados en plantas con origen neotropical, enfocados en comprender e implementar mecanismos de tolerancia a sequía. Las metodologías aquí descritas podrían constituirse en opciones prácticas para mejorar la seguridad alimentaria con miras a contrarrestar las consecuencias negativas del cambio climático antropogénico.

Reaction of the [HC(CMeNAr)2]SnCl (Ar = 2,4,6-Me3C6H2) with “GaI” in THF provided an unexpected transhalogenation reaction product [HC(CMeNAr)2]SnI. The crystal structure shows a tin(II) ion with a distorted tetrahedral pyramidal geometry. Theoretical calculations, using density functional theory (B3LYP), suggest the probable reaction mechanism for transhalogenation. The activation energy for moving from reactant ([HC(CMeNAr)2]SnCl to product [HC(CMeNAr)2]SnI) is only 10.2 kcal/mol. The chloride ion is displaced by the iodine ion, probably by the help of the gallium atom when it is coordinated to the chlorine atom. Keywords: Transhalogenation reaction, “GaI”, β-Diketiminate, X-ray, DFT

The reaction of the tetramethylethylendiamine [(CH3)2NCH2CH2N(CH3)2] with SnCl2 in toluene provided the adduct dichloro-(1,2-bis(dimethylamino)ethane-N,N′)-tin(II) with a tetracoordinate metal center and pseudo-trigonal bipyramidal geometry with a stereochemically active unshared electron pair in its vertex. This compound was characterized by IR, NMR (1H, 13C, and 119Sn) and X-ray studies. The X-ray crystal structure of tin(II) complex shows just one of these three possible isomers. The relative energies of the three different isomers, HOMO and LUMO orbitals, and NMR chemical shifts were calculated, using the density functional theory in order to determine the coordination number. Keywords: Tin(II), TMEDA, X-ray, 119Sn NMR, DFT

Analysis of pulp and peels of Arabica coffee varieties with different external fruit color allowed the identification of 16 phenolic compounds using high-performance liquid chromatography with diode array detection and electrospray ionization multi-stage mass spectrometry (HPLC-DAD-ESI-MSn). Nine chlorogenic acids, three flavan-3-ols, the xanthone mangiferin, the flavonol rutin and two anthocyanins were tentatively identified and quantified. 5-O-Caffeoylquinic acid together with a putative (epi)catechin hexoside were the predominant phenolics detected in the coffee varieties analyzed in this work. Whereas, 3- and 4-caffeoylquinic acids, as well as 5-O-feruloylquinic acid were consistently found in higher quantities in the pulp than in the peels when individual varieties were compared, the opposite was found for the other phenolic compounds detected. Complementary, GC-MS after alkaline hydrolysis and trimethylsilylation permitted the identification of more than 30 constituents, including phenolic compounds and other benzenoids, caffeine, and diverse carboxylic acids. Detected anthocyanins were cyanidin-3-O-glucoside and cyanidin-3-O-rutinoside. Anthocyanin contents in orange-colored berries were lower than those in red fruits, while no anthocyanins were found in yellow-colored fruit. Among non-anthocyanin pigments, we found β-carotene and lutein in all varieties, along with other chloroplast-specific carotenoids in some accessions. In addition, saponification evidenced the presence of several xanthophyll esters. Both, chlorophyll a and b, were detected in the peels of all varieties, while only chlorophyll b was observed in the pulp. Thus, the color of yellow-peeled varieties is due to carotenoids, while that of orange and red-peeled varieties is due to both carotenoids as well as low and high levels of anthocyanins, respectively. Present results point out to the potential use of by-products of particular coffee varieties with differences in the external fruit color as a source of distinctive bioactive compounds, including anthocyanins and carotenoids, with health benefits.

Total lipids, fatty acids, and triacylglycerols in mesocarp and kernels from Costa Rican Acrocomia aculeata fruits were characterized at three maturity stages. C16:0 and C18:1n9 were the most abundant fatty acids in the mesocarp. C12:0, C14:0, C16:0, and C18:1n9 prevailed in the kernel oil. Comprehensive HPLC-DAD-APCI-MS and ESI-MSn analysis revealed 125 triacylglycerols with equivalent carbon numbers ranging between 28 and 52. Mesocarp oils mainly contained unsaturated triacylglycerols composed of long-chain fatty acids. In the kernel, high proportions of saturated triacylglycerols with medium-chain fatty acids were observed. Within the maturity stages assessed, fatty acid and triacylglycerol compositions remained unaffected by ripening. Total lipids in the mesocarp increased from 12.1 to 23.4% with progressing maturity, whereas those in the kernel constantly ranged between 54.1 and 56.1%. For the recovery of A. aculeata oil, utilization of all fruits in a bunch at progressed maturity is possible without affecting the composition of its major lipid fractions. Keywords: Total lipids, Macauba, Fruit ripening, Fatty acids, Triacylglycerols, HPLC linear retention indices

Abstract The progress made by the scientific community in emerging photovoltaic technologies over the past two decades has been outstanding. Numerous methods have been developed for the preparation of hybrid organic–inorganic perovskite solar cells. The power conversion efficiency has been up to 14% by a one-step vacuum deposition technique. A serious concern is the toxicity of the materials. In this review, several methods aimed at resolving these problems to some extent have been compiled, including eco-friendly synthesis. Further efficiency enhancements are expected following optimization, and a better fundamental understanding of the internal electron charge transfer, electron–hole diffusion to the corresponding layers, flexibility, and stability-dependent bandgaps is reported. This paper explores the green synthesis of organic–inorganic perovskites for industrialization. Concerning the above facts, a simple low-cost model called “dispersed photovoltaic cells” is presented.

Organoboron compounds are attracting immense research interest due to their wide range of applications. Particularly, low-coordinate organoboron complexes are receiving more attention due to their improbable optical and nonlinear optical properties, which makes them better candidates for medical applications. In this review, we summarize the various synthetic methods including multicomponent reactions, microwave-assisted and traditional pathways of organoboron complexes, and their optical and nonlinear properties. This review also includes the usage of organoboron complexes in various fields including biomedical applications.

Aproximadamente el 87,5 % de las especies de plantas con flores son polinizadas por animales, sin embargo, la magnitud del impacto en la polinización de plantas por parte de los roedores, grupo al que pertenecen las ardillas, ha sido subestimada por la falta de información. Documentamos por primera ocasión consumo de las inflorescencias, néctar o polen de maguey (Agave sp.) por la ardilla de Peters (Parasciurus oculatus). Es necesario continuar el monitoreo de los polinizadores de los magueyes, para determinar el papel que juegan las ardillas en los procesos de polinización o depredación de estas plantas.

A protocol to propagate papaya hybrid plants through indirect somatic embryogenesis was developed considering the effect of explant type, culture system, particular cytokinins and encapsulation, in different stages of the process. Optimal 2,4-dichlorophenoxyacetic acid (2,4-D) concentrations for non-embryogenic callus formation ranged between 9.0 and 27.1 μM in half-cut seeds, while higher concentrations were harmful. Non-embryogenic callus was also obtained with 22–158 μM 2,4-D from hypocotyl segments. Callus with embryogenic structures was only obtained in half-cut seeds cultured in the darkness on half-strength Murashige and Skoog culture medium supplemented with 2,4-D, while hypocotyl segments and isolated zygotic embryos failed to produce this type of callus regardless of the 2,4-D and sucrose (30 and 70 g l-1) concentrations tested in this study. Both, embryogenic callus development and quantity of somatic embryos formed per embryogenic callus, which ranged between 11 and 31 units after 14 months, required 2,4-D, but without any effect of the concentration. Histological studies confirmed the multicellular origin of the somatic embryos. In further steps, liquid medium induced over four times more somatic embryos than agar-gelled medium and showed significantly higher production of globular somatic embryos (85 vs. 57%). Both, 6-benzyladenine (BA) and meta-topolin (Mtop) stimulated sprouting (40–45%) of the somatic embryos (development of shoots only) in concentrations of up to 2.7 and 10 μM, respectively. Sprouting probability showed a 2nd order polynomial trend despite the range of concentration used for each cytokinin. This is the first report about the positive effect of Mtop on the apical shoot development of Carica papaya somatic embryos known to the authors. Radicle growth was observed in 5% or less of the cultivated embryos, regardless of the BA concentration. Finally, all encapsulation conditions tested (2.5, 3.5, and 4.5% sodium alginate, combined with 50 and 100 mM CaCl2) reduced sprouting of somatic embryos when compared to the non-encapsulated ones, whereas capsule hardness showed low correlation with embryo sprouting. Embryos were further cultivated until they became plantlets approximately 5 cm long. They were acclimatized and afterward planted in the field, where they flowered and produced fruit.

In this paper, we report the synthesis and characterization of new boron compounds derived from dithiooxamides. The compounds were characterized by NMR (1H and 13C), UV-vis, fluorescence spectroscopy, and high resolution mass spectrometry. The crystal structure of the mononuclear boron compound was determined by single-crystal X-ray diffraction analysis. The photophysical properties of the boron compounds were investigated, and we found moderate fluorescence emission (compound 2 ΦF: 4.07% and compound 4 ΦF: 2.89%). We also observed that the mononuclear complex presented greater stability. Compound 4 showed interesting luminescent properties; in solid state, it exhibited an increase in fluorescence by mechanostimuli by changing to a bright red color, and also in solution, it showed a decrease in fluorescence intensity when oxygen and air were supplied to the solution.

Título en ingles: Factors affecting in vitro somatic embryogenesis of palms (Arecaceae) Resumen La embriogénesis somática (ES) es una vía de desarrollo in vitro que presenta una serie de ventajas sobre otras técnicas utilizadas para la regeneración de palmas. Esta técnica tiene gran potencial para superar las limitaciones observadas al tratar de propagar clonalmente estas plantas utilizando yemas basales. A pesar de la conocida recalcitrancia que presentan las palmas al cultivo in vitro, si se utilizan los reguladores de crecimiento apropiados, el tipo y el estado de desarrollo del explante adecuados, así como genotipos con buena respuesta, es muy probable que se obtengan buenos resultados. Esto ha sido demostrado parcialmente en Phoenix dactylifera (palma dátil), Elaeis guineensis (palma aceitera), Bactris gasipaes (pejibaye) y Cocos nucifera (coco). También se ha logrado generar protocolos eficientes en otras palmas menos estudiadas, como Geonoma gamiova (una palma ornamental), Euterpe edulis (palmito dulce) y Areca catechu (palma de betel). La inducción de ES se ha conseguido principalmente con el uso de auxinas. De ellas, la que se ha utilizado con más frecuencia es el ácido 2,4-diclorofenoxiacético (2,4-D), aunque en algunos casos (como en pejibaye y palma aceitera) se ha usado picloram y dicamba, también con buenos resultados. Los explantes más utilizados han sido inflorescencias, ápices y segmentos basales de hojas, todos con un estado de desarrollo incipiente. También se ha visto que el tamaño del explante y el medio de cultivo juegan un papel importante en la respuesta. En este trabajo se presenta una recopilación de los trabajos más importantes sobre ES en esta familia de plantas y del efecto de varios factores sobre su establecimiento y desarrollo. Palabras clave: Explante; genotipo; medio de cultivo; regeneración; reguladores de crecimiento AbstractSomatic embryogenesis (SE) is an in vitro developmental pathway that exhibits a number of advantages over other techniques for regeneration of palms. This technique has great potential to overcome the limitations observed when trying to propagate these plants clonally using basal buds. Despite the known recalcitrance of palms for in vitro culture, good results can be obtained by using the appropriate growth regulators, explant type and developmental stage, as well as responsive genotypes. This has been partially observed in Phoenix dactylifera (date palm), Elaeis guineensis (African oil palm), Bactris gasipaes (peach palm) and Cocos nucifera (coconut). Efficient protocols have been also generated in less-studied palms, such as Geonoma gamiova (an ornamental palm), Euterpe edulis (Assai palm) and Areca catechu (areca palm). Induction of SE has been achieved mainly through the use of auxins. Of these, 2,4-dichlorophenoxyacetic acid (2,4-D) has been used most frequently, although in some cases (such as in peach palm and African oil palm) picloram and dicamba have been employed also with good results. The most commonly used explants are young inflorescences, apical buds and leaf-basal segments. Explant size and culture medium also play an important role in obtaining good results. This review presents a compilation of the most important publications on SE in this plant family and the effect of various factors on induction and development of this pathway. Key words: Culture medium; explants; genotype; plant growth regulators; regeneration

Se evaluó el uso de abonos foliares comerciales para el cultivo in vitro de microestacas de papa cv. Atzimba, como alternativa de bajo costo a las sales minerales de Murashige y Skoog (MS). Microestacas de plantas de papa cultivadas en medio MS se transfirieron a 5 combinaciones de abonos, 2 equiparadas molarmente en su composición al MS (AMSF, AMSF+Intra) y las otras 3 (MF+Intra, MF+Micro+Intra, MF+Foli+Agro+Intra), ajustadas a los contendidos de N, P, K y Mg del MS. El medio MS se incluyó como testigo. En todos los casos se realizó transferencias mensuales. Durante 5 meses se evaluó, semanalmente, la altura de la planta, el número de yemas y raíces, clorosis, y, al final del 5to subcultivo, el peso fresco. Los mejores resultados se obtuvieron con los medios MS, AMSF y AMSF+Intra. En los demás se observó una disminución gradual del crecimiento de las plantas, y un incremento en la clorosis. De las formulaciones con buenos resultados, AMSF fue la más barata (US$0,012 l-1), seguida por AMSF+Intra (US$ 0,025 l-1), y el MS (US$ 3,411 l-1). Los resultados obtenidos permiten considerar la factibilidad de emplear abonos foliares de bajo costo, como reemplazo de las sales minerales de alta pureza en la elaboración del medio de cultivo MS, para la propagación in vitro de plantas de papa cv. Atzimba, al menos por períodos de tiempo limitados.

In the title compound, C14H10FNO2, the benzene rings make a dihedral angle of 57.50 (13)°, and the molecule has an E configuration about the C=N bond. In the crystal, molecules are linked via pairs of O—H...O hydrogen bonds, forming inversion dimers.

Título en ingles: Factors affecting in vitro somatic embryogenesis of palms (Arecaceae) Resumen La embriogénesis somática (ES) es una vía de desarrollo in vitro que presenta una serie de ventajas sobre otras técnicas utilizadas para la regeneración de palmas. Esta técnica tiene gran potencial para superar las limitaciones observadas al tratar de propagar clonalmente estas plantas utilizando yemas basales. A pesar de la conocida recalcitrancia que presentan las palmas al cultivo in vitro, si se utilizan los reguladores de crecimiento apropiados, el tipo y el estado de desarrollo del explante adecuados, así como genotipos con buena respuesta, es muy probable que se obtengan buenos resultados. Esto ha sido demostrado parcialmente en Phoenix dactylifera (palma dátil), Elaeis guineensis (palma aceitera), Bactris gasipaes (pejibaye) y Cocos nucifera (coco). También se ha logrado generar protocolos eficientes en otras palmas menos estudiadas, como Geonoma gamiova (una palma ornamental), Euterpe edulis (palmito dulce) y Areca catechu (palma de betel). La inducción de ES se ha conseguido principalmente con el uso de auxinas. De ellas, la que se ha utilizado con más frecuencia es el ácido 2,4-diclorofenoxiacético (2,4-D), aunque en algunos casos (como en pejibaye y palma aceitera) se ha usado picloram y dicamba, también con buenos resultados. Los explantes más utilizados han sido inflorescencias, ápices y segmentos basales de hojas, todos con un estado de desarrollo incipiente. También se ha visto que el tamaño del explante y el medio de cultivo juegan un papel importante en la respuesta. En este trabajo se presenta una recopilación de los trabajos más importantes sobre ES en esta familia de plantas y del efecto de varios factores sobre su establecimiento y desarrollo. Palabras clave: Explante; genotipo; medio de cultivo; regeneración; reguladores de crecimiento Abstract Somatic embryogenesis (SE) is an in vitro developmental pathway that exhibits a number of advantages over other techniques for regeneration of palms. This technique has great potential to overcome the limitations observed when trying to propagate these plants clonally using basal buds. Despite the known recalcitrance of palms for in vitro culture, good results can be obtained by using the appropriate growth regulators, explant type and developmental stage, as well as responsive genotypes. This has been partially observed in Phoenix dactylifera (date palm), Elaeis guineensis (African oil palm), Bactris gasipaes (peach palm) and Cocos nucifera (coconut). Efficient protocols have been also generated in less-studied palms, such as Geonoma gamiova (an ornamental palm), Euterpe edulis (Assai palm) and Areca catechu (areca palm). Induction of SE has been achieved mainly through the use of auxins. Of these, 2,4-dichlorophenoxyacetic acid (2,4-D) has been used most frequently, although in some cases (such as in peach palm and African oil palm) picloram and dicamba have been employed also with good results. The most commonly used explants are young inflorescences, apical buds and leaf-basal segments. Explant size and culture medium also play an important role in obtaining good results. This review presents a compilation of the most important publications on SE in this plant family and the effect of various factors on induction and development of this pathway. Key words: Culture medium; explants; genotype; plant growth regulators; regeneration

La producción de metabolitos secundarios en cultivos celulares de plantas puede ser de interés para obtener compuestos difíciles de sintetizar o aislar de otras fuentes, lo cual generalmente se relaciona con un alto valor económico, aunque también puede ser útil para ayudar a dilucidar las vías metabólicas involucradas en la síntesis de estos compuestos. En este trabajo se presenta una descripción general de las antocianinas, un grupo de pigmentos de gran importancia para la industria, complementada con la referencia de los trabajos científicos recientes que se han publicado sobre la producción in vitro de las mismas. Con relación a esto último, se hace una descripción del efecto de cambios en las condiciones de cultivo, de la adición de precursores, del uso de reguladores de crecimiento, así como de la utilización de inductores y factores de estrés sobre la producción de estos compuestos. Finalmente, se hace mención al uso de raíces en cabellera, en inglés “hairy roots”, obtenidas mediante el uso de Agrobacterium rhizogenes, para la producción de estos compuestos.

El objetivo de esta revisión bibliográfica fue describir las principales técnicas para conservación in vitro de germoplasma por corto y largo plazo. Estas técnicas permiten el establecimiento de bancos de germoplasma. Este trabajo se centra en su uso en cultivos tropicales. Las técnicas de conservación in vitro han permitido la preservación de recursos fitogenéticos para su uso ulterior con fines de mejoramiento genético, investigación y de seguridad alimentaria. En muchos centros de investigación se han utilizado estas técnicas para almacenar tejidos y semillas de cultivos tropicales, los cuales de forma convencional son difíciles de preservar.

The title salt, C21H27N2+·Cl− resulted from the condensation between 2,6-dimethylaniline and acetylacetone in acidified ethanol. The bulky cation is stabilized in a β-iminoenamine tautomeric form, and presents a W-shaped conformation. The benzene rings are arranged almost parallel, with a dihedral angle of 6.58 (4)° between the mean planes. Both N—H groups in the cation form strong hydrogen bonds with two symmetry-related chloride anions. The resulting supramolecular structure is a one dimensional polymer running along [001], alternating cations and anions. The π–π interaction observed in the molecule, characterized by a centroid–centroid separation of 4.298 (4) Å, is thus extended to the chains, with separations of 5.222 (4) Å between benzene rings of neighbouring cations in the crystal.

Efficient selection of hybrid plants produced by protoplast fusion is very important. Several advances have been made on the subject in recent decades. The methods used for the identification of somatic hybrids include selection by morphological characteristics (growth, leaf, stem, flower or fruit type, flower color or type of inflorescence), micromanipulation (or manual selection), flow cytometry, complementation, chromosome counting, isozyme detection and the use of molecular markers, such as random amplification of polymorphic DNA (RAPD), genomic in situ hybridization (GISH), simple sequence repeats or microsatellites (SSR), the inter-simple sequence repeats (ISSR), restriction fragment length polymorphisms (RFLP) and amplified fragment length polymorphisms (AFLP). Isozyme analysis was a very common selection method for many years. Although, molecular techniques based on DNA have become reliable methods to detect somatic hybrids. Flow cytometry offers a more rapid and sensitive method for the selection of hybrid cells. However, the equipment needed for its implementation is very expensive. Use of more than one method for early detection of somatic hybrids increases the selection efficiency. This review describes the methods used for detection of somatic hybrids and presents a list of examples on their use from 1974 on. Key words: isozymes, molecular techniques

In vitro flowering can be induced at different stages during development of in vitro plants by changes in chemical and physical factors related to the tissue culture process. Among the physical factors, photoperiod and temperature have been studied more detailed. Their inductive effect may vary in different species. Some physical factors can also be replaced by chemical stimuli. The chemical factors more frequently described in the literature are some growth regulators and the sucrose/nitrogen ratio. Cytokinins may induce flower development from various organs, but high concentrations can inhibit flowering and cause sprouting of vegetative buds. Gibberellins and polyamines (mostly spermidine) have a positive effect on flower induction. While, ethylene and auxin seem to be powerful inhibitors of in vitro flowering. However, auxins seem to be necessary during the early stages of floral development. An increase in the concentration of sucrose in the culture medium favor development of flowers in vitro, whereas a high concentration of nitrogen can stimulate vegetative growth of explants. Nevertheless, if the nitrogen concentration is too low, explants do not develop well. The aim of this literature review is to discuss most common factors related to in vitro flowering and to list the most relevant scientific literature about the subject from 1980 on. Key words: flower induction, growth regulators, inducers, tissue culture Abreviaturas: 2,4-D Ácido 2,4-diclorofenoxiacético, 2iP 2–isopentiladenina, ABA Ácido abscísico, AC Agua de coco, AG3 Ácido giberélico, AIA Ácido indol acético, AIB Ácido indol butírico, ANA Ácido naftalen acético, BAP Benciladenina, CAct Carbón activado, CasHid Caseína hidrolizada, DSDPs Plantas de día corto desplazado, GAx Giberelina x, LDPs Plantas de día largo, MES Ácido 2 (N-morfolino) etanosulfónico, MS Murashige y Skoog (1962), MT Murashige y Tucker (1969), PSF Plantas sensibles al fotoperíodo, Put Putrescina, PVP Polivinilpirrolindona, SAM S-adenosil-L-metionina, SAMDC S-adenosil-L-metionina descarboxilasa, SDPs Plantas de día corto, Spd Espermidina, Spm Espermina, TDZ Tidiazuron

La variación somaclonal es la variación genética o epi genética que se genera durante el cultivo in vitro de plantas (cultivos celulares de tejidos u órganos) que provenga de células somáticas. En programas de mejoramiento genético, la variación somaclonal puede constituirse en un recurso importante que genera variabilidad. Sin embargo, durante la micropropagación y en bancos de germoplasma in vitro, este tipo de variación es indeseable. En vista de lo anterior, se han utilizado una serie de técnicas moleculares para su detección. En esta revisión bibliográfica se presenta una descripción de las técnicas moleculares útiles en la detección de variación somaclonal in vitro y, además, una recopilación de trabajos publicados sobre la detección de variación somaclonal por medio de técnicas moleculares.

Los hallazgos radiográficos de la hipertensión renovascular se pueden resumir así: 1. funcionales: a. nefrograma disminuído, b. demora en la aparición o eliminación retardadas, c. hiperconcentración en fases tardías. 2. anatómicos: a. diferencia de tamaño, sin cambios en grosor de la cortical, b. asimetría en longitud con adelgazamiento del parenquima, c. sistema pielocalicilar disminuído de tamaño, pero morfológicamente normal, d. adelagazamiento de la cortical, e. circulación colateral. 3. funcionales y anatómicos: a. disminución de la función renal, sin asimetría en la longitud, con o sin adelgazamiento, b. asimetría, adelgazamiento y función.