Summary: Echinocactus parryi is a threatened and endemic species of the municipality of Juarez, Chihuahua, Mexico that presents important limitations for its propagation. The objective of this study was to evaluate the effect of growth regulators, calcium concentration (Ca2+), environmental pH and gelling concentration in the morphogenetic response of E. parryi. The seeds were germinated in Murashige and Skoog (MS) medium at 25% of the concentration of their salts (¼ MS). Epicotyls were cultured in an inverted position in media with different concentrations of 6-benzylaminopurine (BAP) (0-10 mg L-1), indole-3-acetic acid (AIA) (0-0.5 mg L-1), pH 5.7 and 8, Ca2+ (13.2 µM and 26.4 µM) and agar (7 and 10 g L-1). The highest sprout formation (2.9 sprouts per explant) was obtained in MS medium with 2 mg L-1 of BAP combined with 0.5 mg L-1 of AIA, 13.2 µM of Ca2+, pH 8, and 7 g L-1 of agar, at 120 days of culture. The sprouts were transferred to MS medium with 2,3,5 tri‑iodobenzoic acid (TIBA) (0, 0.5, 1 and 2 mg L-1) to induce root formation. The highest rooting (70.5%) was obtained in medium with 0.5 mg L-1 of TIBA. The survival of the plants was 58% at 5 months. This is the first report that describes the in vitro regeneration of E. parryi and constitutes an important advance for its propagation and conservation.

Resumen: Echinocactus parryi, es una especie amenazada y endémica del municipio de Juárez, Chihuahua, México que presenta importantes limitantes para su propagación. El objetivo de este trabajo fue estudiar el efecto de los reguladores de crecimiento, concentración de calcio (Ca2+), pH del medio y concentración de gelificante en la respuesta morfogenética de E. parryi. Las semillas se germinaron en medio de Murashige y Skoog (MS) al 25% de la concentración de sus sales (¼ MS). Los epicotilos se cultivaron en posición invertida en medios con diferentes concentraciones de 6-bencilaminopurina (BAP) (0-10 mg L-1), ácido indol-3-acético (AIA) (0-0.5 mg L-1), pH 5.7 y 8, Ca2+ (13.2µM y 26.4 µM) y agar (7 y 10 g L-1). La mayor formación de brotes (2.9 brotes por explante) se obtuvo en medio MS con 2 mg L-1 de BAP combinado con AIA 0.5 mg L-1, 13.2 µM de Ca2+, pH 8 y 7 g L-1 de agar a los 120 días. Los brotes generados se transfirieron a medio MS con ácido 2,3,5 tri-iodobenzoico (TIBA) (0, 0.5, 1 y 2 mg L-1) para inducir la formación de raíz. El mayor enraizamiento (70.5%) se obtuvo en medio con 0.5 mg L-1 de TIBA. La sobrevivencia de las plantas fue del 58% a los 5 meses. Este es el primer reporte que describe la regeneración in vitro de E. parryi y constituye un avance importante para su propagación y conservación.

Abstract Introduction: The Asparagaceae family includes several genera adapted to survive at high temperatures and with low water availability. These include Agave, Beaucarnea, Dasylirion, Nolina and Yucca. Mexico has a great biodiversity in these plant groups, as well as an ancestral tradition regarding its use. In vitro propagation systems are efficient for the production of these plants and can be used to perform various types of studies. Among these are the studies of tolerance to heavy metals, which can serve to determine which species are suitable for reforestation and regeneration of areas contaminated by mining activities. Method: In this work, 20 species of the family Asparagaceae were propagated in vitro and their rooting process was evaluated in culture media added with Cd, Cu, Cr, Fe, Mn, Pb and Zn. The development of roots in the presence of these metals was analyzed and its absorption capacity was determined by flame atomic absorption spectrophotometry. With these data, translocation and bioaccumulation factors were calculated in order to characterize the response of each species to heavy metals. Results: The highest number of shoots occurred in the species Beaucarnea recurvata, which generated 5.7 shoots per explant and Nolina durangensis with 5.6. Chromium treatment was toxic for most species. Agave celsii, A. chiapensis, A. obscura, A. palmeri and A. salmiana formed roots in all treatments. According to translocation and bioaccumulation factors, the analyzed species were classified as phytostabilizers, exclusors, bioaccumulators and indicators. The species A. chiapensis, A. obscura and A. palmeri were bioaccumulators for Mn. A. celsii and A. salmiana presented mechanisms of phytostabilization and exclusion. Conclusion: In vitro propagation allows to work and study a wide range of species in the presence of contaminants. The Agave genus is tolerant to metals and can be used to phytostabilize and remediate contaminated soils.

Resumen Introducción: La familia Asparagaceae incluye varios géneros adaptados para sobrevivir a altas temperaturas y con baja disponibilidad de agua. Entre éstos destacan Agave, Beaucarnea, Dasylirion, Nolina y Yucca. México cuenta con una gran biodiversidad de estos grupos vegetales, así como con una tradición ancestral en cuanto a su uso. Los sistemas de propagación in vitro son eficientes para la producción de estas plantas, y además pueden ser usados para llevar a cabo diversos tipos de estudios. Entre estos, están los estudios de tolerancia a metales pesados, los cuales pueden servir para determinar qué especies son aptas para la reforestación y regeneración de áreas contaminadas por actividades mineras. Método: En este trabajo se propagaron in vitro 20 especies de la familia Asparagaceae, y se evaluó su proceso de enraizamiento en medios de cultivo adicionados con Cd, Cu, Cr, Fe, Mn, Pb y Zn. Se analizó el desarrollo de las raíces en presencia de estos metales y se determinó su capacidad de absorberlos mediante espectrofotometría de absorción atómica de llama. Con estos datos se calcularon los factores de translocación y bioacumulación con el fin de caracterizar la respuesta de cada especie ante los metales pesados. Resultados: El mayor número de brotes se presentó en las especies Beaucarnea recurvata con 5.7 y Nolina durangensis con 5.6 brotes por explante, respectivamente. El tratamiento con cromo fue tóxico para la mayoría de las especies. Agave celsii, A. chiapensis, A. obscura, A. palmeri y A. salmiana formaron raíz en todos los tratamientos con metales. De acuerdo a los factores de translocación y bioacumulación las especies analizadas se clasificaron como fitoestabilizadoras, exclusoras, bioacumuladoras e indicadoras. Las especies A. chiapensis, A. obscura y A. palmeri fueron bioacumuladoras para Mn. A. celsii y A. salmiana presentaron mecanismos de fitoestabilización y exclusión. Conclusión: La propagación in vitro permite generar grandes cantidades de plantas y además estudiar sus respuestas ante la presencia de contaminantes. El género Agave mostró ser tolerante a los metales, por lo que se puede usar para fitoestabilizar y remediar suelos contaminados.

Cacti species are plants that are well adapted to growing in arid and semiarid regions where the main problem is water availability. Cacti have developed a series of adaptations to cope with water scarcity, such as reduced leaf surface via morphological modifications including spines, cereous cuticles, extended root systems and stem tissue modifications to increase water storage, and crassulacean acid metabolism to reduce transpiration and water loss. Furthermore, seeds of these plants very often exhibit dormancy, a phenomenon that helps to prevent germination when the availability of water is reduced. In general, cactus species exhibit a low growth rate that makes their rapid propagation difficult. Cacti are much appreciated as ornamental plants due to their great variety and diversity of forms and their beautiful short-life flowers; however, due to difficulties in propagating them rapidly to meet market demand, they are very often over-collected in their natural habitats, which leads to numerous species being threatened, endangered or becoming extinct. Therefore, plant tissue culture techniques may facilitate their propagation over a shorter time period than conventional techniques used for commercial purposes; or may help to recover populations of endangered or threatened species for their re-introduction in the wild; or may also be of value to the preservation and conservation of the genetic resources of this important family. Herein we present the state-of-the-art of tissue culture techniques used for ornamental cacti and selected suggestions for solving a number of the problems faced by members of the Cactaceae family.

In order to provide an alternative to conventional propagation, a protocol was developed for the in vitro multiplication of four Mexican species of Quercus, which are exploited to produce timber and coal and are nowadays threatened. Multiple shoot induction from zygotic embryos of Quercus castanea, Q. eduardii, Q. resinosa and Q. rugosa cultured on Murashige and Skoog medium supplemented with 6-benzylamino-purine (BA) or kinetin is described. Results showed that both cytokinins affected shoot regeneration, where BA exhibited highest efficiency. Higher shoot proliferation frequency was observed in Q. castanea and Q. eduardii (91.7%), giving an average of 6.3 and 6.5 shoots per explant on medium with 3.0 and 4.0 mg 1-1 BA, respectively. For Q. resinosa, the best response was obtained with BA at 3.0 mg 1-1 producing 3.8 shoots per explant. Finally, Q. rugosa yielded 3.6 shoots per explant with 1.0 mg 1-1 BA. Shoots were excised from the seedlings and transferred to half-strength medium supplemented with 10.0 mg 1-1 indole-3-butyric acid for two or five days, and then transfer to half-strength medium for rooting. Under these conditions, 100, 100, 66.7 and 83.3% of the shoots of Q. castanea, Q. eduardii, Q. resinosa, and Q. rugosa generated roots, respectively. Plantlets were successfully acclimated to soil in greenhouse conditions with survival frequencies of 80% for Q. castanea, 83.3% for Q. eduardii, 73.3% for Q. resinosa, and 70.0% for Q. rugosa. This in vitro propagation method can contribute to the production of plants for reforestation thus supporting the conservation and rational use of these species.

Con el fin de ofrecer una alternativa a los sistemas convencionales de propagación, se desarrolló un protocolo para la multiplicación in vitro de cuatro especies mexicanas de Quercus, las cuales son explotadas para la producción de madera y carbón y están actualmente amenazadas. Se describe la inducción de brotes múltiples a partir de embriones cigóticos de Quercus castanea, Q. eduardii, Q. resinosa and Q. rugosa cultivados en medio de Murashige y Skoog enriquecido con 6-bencilaminopurina (BA) o cinetina. Los resultados mostraron que ambas citocininas afectaron la regeneración de brotes, donde la BA mostró la mayor eficiencia. La mayor frecuencia de proliferación de brotes se observó en Q. castanea y Q. eduardii (91.7%), dando promedios de 6.3 y 6.5 brotes por explante al utilizar 3.0 y 4.0 mg 1-1 de BA, respectivamente. Para Q. resinosa, la mejor respuesta fue obtenida con BA a 3.0 mg 1-1 produciendo 3.8 brotes por explante. Finalmente, Q. rugosa produjo 3.6 brotes por explante con 1.0 mg 1-1 de BA. Los brotes fueron separados de las plántulas y transferidos a un medio basal a la mitad de su concentración enriquecido con 10.0 mg 1-1 de ac. indolbutírico por dos a cinco días, y luego transferidos a medio a la mitad de su concentración para su enraizamiento. Bajo estas condiciones, el 100, 100, 66.7 y 83.3% de los brotes de Q. castanea, Q. eduardii, Q. resinosa y Q. rugosa generaron raíces, respectivamente. Las plántulas fueron aclimatadas a suelo en condiciones de invernadero de manera exitosa con frecuencias de sobrevivencia de 80% para Q. castanea, 83.3% para Q. eduardii, 73.3% para Q. resinosa, y 70.0% para Q. rugosa. Este método de propagación in vitro puede contribuir a la producción de plantas con fines de reforestación apoyando así la conservación y uso racional de estas especies.

A green chemistry methodology for fast and simple bioreduction of aromatic aldehydes to their corresponding aromatic alcohols was achieved using an extract of Aloe vera in aqueous suspension. Under microwave irradiation, this reaction was performed in a short reaction time. This methodology is an alternative preparation for aromatic alcohols that are extensively utilized as industrial and cosmetic reagents.

Se desarrolló una metodología de química verde para la bioreducción rápida y sencilla de aldehídos aromáticos a alcoholes aromáticos utilizando un extracto de Aloe vera en suspensión acuosa. Por medio de radiación de microondas, esta reacción se llevo a cabo en un periodo de tiempo muy corto. El procedimiento desarrollado es una ruta alterna para preparar alcoholes aromáticos, los cuales son reactivos muy utilizados en la industria y en la preparación de cosméticos.

We have established the conditions to obtain in vitro root cultures of Thypha latifolia and Scirpus americanus and have investigated their capacity to remove Pb(II), Mn(II) and Cr(III) from the culture medium. The best conditions for the in vitro culture growth were: an inoculum of 0.2 g of T. latifolia roots and 0.05 g of S. americanus roots (fresh weight), Murashige-Skoog medium and 2 mg L-1of indolacetic acid. The T. latifolia and S. americanus root cultures were cultivated onto media containing Cr (15 µg L-1), Pb (60 µg L-1) or Mn (1.8 mg L-1). Both species were able to remove Pb and Cr near to 100% and 71-100% of Mn from the medium solution during the 6-8 days of experimentation. According to metal concentrations removed from the medium containing the growing root mass, the in vitro root culture of S. americanus can be considered as an accumulator for Pb (157.73 µg g-1), Cr (55.6 µg g-1) and Mn (5000 µg g-1).