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ResumenPara contrarrestar los efectos negativos del proceso degenerativo en semillas, se han empleado diversos tratamientos pregerminativos con éxito parcial en diversas especies, como el quimio acondicionamiento y el hidro acondicionamiento. Para evaluar efecto de la imbibición sobre la calidad fisiológica en semillas de jitomate se utilizaron muestras de 25 semillas envejecidas naturalmente las cuales fueron sometidas al pretratamiento (imbibición en agua destilada con aireación enérgica, 20 h y secado, 18 h) y, para germinar, colocadas en cajas Petri sobre papel sanita, humedecidas con 3.5 ml de agua destilada y colocadas inmediatamente en desecadores de vidrio ajustados a 200, 400 y 600 mm de Hg (vacío), donde fueron conservadas 12 días a 25±1 °C. La germinación total en porcentaje (PG) viabilidad en porcentaje (VIA), peso de materia seca de la parte aérea (PSMA) y de la radícula (PSMR) fue determinada. Hubo diferencias significativas (p< 0.001) para semillas sometidas al pre-tratamiento en todos los parámetros de calidad fisiológica estudiados. Para la condición de vacío si hubo diferencias (p< 0.001) excepto, en el peso de materia seca de la radícula. En la interacción de semillas sometidas al pretratamiento y condiciones de vacío, no se encontraron significancias estadísticas en todas las variables de respuesta. Las semillas con pre-tratamiento AbstractTo counteract the negative effects of the degenerative process in seeds, have employed various pre-germination treatments with partial success in various species, such as chemotherapy conditioning and hydro conditioning. To evaluate effect of imbibition on physiological quality seeds of tomato samples 25 aged seeds were used naturally which were subjected to pretreatment (imbibition in distilled water with vigorous aeration, 20 h and drying, 18 h) and, to germinate, placed in Petri dishes on paper, moistened with 3.5 ml distilled water and placed immediately in glass desiccators adjusted to 200, 400 and 600 mm Hg (vacuum), which were kept 12 days at 25 ± 1 °C. The total germination percentage (PG) viability percentage (VIA), weight of dry matter of the aerial part (PSMA) and the radicle (PSMR) was determined. There were significant differences (p< 0.001) for seeds subjected to pre-treatment in all physiological quality parameters studied. For vacuum condition if there were differences (p< 0.001) except in the dry matter weight of the radicle. In the interaction of seeds subjected to pretreatment and vacuum conditions, no statistical significances were found in all response variables. The seeds with pretreatment started faster germination, seeing reflected in greater VIA, PSMA and PSMR, compared seeds without pretreatment. For vacuum 1766 Rev. Mex. Cienc. Agríc. Vol.7 Núm. 7 28 de septiembre -11 de noviembre, 2016 Claudia Pérez Mendoza et al.iniciaron más rápido la germinación, viéndose reflejado en una mayor VIA, PSMA y PSMR en comparación, a las semillas sin pretratamiento. Para las condiciones de vacío se observó que los mayores valores de PG con 82.9%, V...

The Guarianthe skinneri orchid is included in NOM-059-ECOL-2010, Mexico standard as an endangered species. In order to study PGPR (promoting growth plant rhizobacteria) from this orchid, 10 roots were collected from different plants to isolate bacteria associated with the roots, which were analyzed by in vitro tests such as: production of AIA, nitrogen fixation, interaction with the mycorrhizal fungus Thanatephorus sp. strain RG26 and phosphate solubilization. We obtain 71 bacterial isolates, 10 strains of them were characterized by sequencing with the 16d rDNA marker identifying six bacteria: Sphingomonas sp. Sinorhizobium sp. Bacillus sp. Nocardia cerradoensis, Bacillus megaterium and Burkholderia phytofirmans. We observed that the bacterium Sinorhizobium sp. produced a greater amount of AIA (69.189 μg/ml) and Bacillus sp. performed greater acetylene reduction (10.251 nmol cultivo/96h). In the interactions of the bacteria and the fungus RG26, four categories were presented (extremely positive, positive, antagonism 50-50 and inhibition). In relation to the solubilization of phosphate, Burkholderia phytofirmans presented higher IS after 48 and 96 hr with an IS of 3.11 and 3.48, respectively. The results indicate that Bacillus sp. it could have the best characteristics to promote the development of the G. skinneri orchid by inoculating seeds and seedlings.

Las rizobacterias promotoras del crecimiento vegetal interactúan con distintos tratamientos o metales presentes en suelos enriquecidos con composta, que mejoran las condiciones del suelo y benefician al crecimiento de la planta. El objetivo fue analizar el desarrollo de Medicago sativa con rizobacterias en condiciones de estrés. Se germinaron semillas de alfalfa de dos variedades (Victoria y Aragón), inoculadas con dos rizobacterias; se trasplantaron en invernadero y se adicionó sulfato de cobre, composta, en dos tipos de suelo (regado con aguas residuales y aguas de pozo). El suelo residual presentó significancia en el número de hojas y altura de la planta, la variedad Victoria en el número de hojas, la cepa M40 en el diámetro del tallo y la composta con 37 g en longitud de raíz. El uso de rizobacterias asociadas a la raíz en combinación con composta y metales pesados permite desarrollar tecnologías con beneficios para la Medicago sativa.

<p><strong>Background:</strong> Heavy metals are perceived as the most persistent and dangerous. Cu is essential for plants, in excess it causes detrimental effects on plants and human health. Plant growth promoting bacteria have been mainly used in agriculture to promote seed germination, plant vigor and growth, and improve crop yields. <strong>Objective:</strong> To analyse the effect of germination in two roselle varieties that were inoculated with extracellular plant growth-promoting rhizobacteria of the genus <em>Pseudomonas</em> and in seven solutions of copper sulphate pentahydrate. <strong>Methodology:</strong> Roselle seeds were germinated in copper sulphate solutions, the seeds were inoculated with bacterial suspensions of two strains of <em>Pseudomonas</em> M40 and M67, the germination percentages were determined and vigour tests were also carried out. <strong>Results:</strong> The effect of copper sulphate on germination was significant in the interaction between main factors, but no significance was found in the effect of the strains and their interaction with the varieties. In the vigour tests, significance was detected between factors of stem dry weight, root and stem length, and strains.<strong> Implications:</strong> The tolerance of the seeds to copper sulphate, to know if it has an effect of promoting germination or, on the contrary, inhibits it. <strong>Conclusion:</strong> copper sulphate has the effect of promoting the germination of roselle seeds. Jamaica has a potential effect of phytoremediation of metals in combination with the inoculation of rhizobacteria that promote plant growth.</p>