Allelopathic potential of invasive Ulmus pumila on understory plant species

In Petriplate bioassay and Pot culture, we studied the allelopathic potential of leaf litter of Siberian elm (Ulmus pumila L.) invasive tree species on the germination and growth of three herbaceous plant native species (Dactylis glomerata L., Trifolium repens L. and Chenopodium album L.) commonly found in riparian understory communities. Two assays were done with leaf litter of U. pumila from riverine ecosystems (i). the effects of aqueous litter extracts in Petri dish assays and (ii). the effect of litter residues in pot experiments. The leaf litter extracts inhibited the radicle growth of D. glomerata and T. repens but did not effect the germination. However in pots, leaf litter inhibited the germination speed of C. album and growth of D. glomerata and T. repens. Our results showed the allelopathic potential of U. pumila litter, which reduced the growth of understory species (T. repens and D. glomerata). In the litter of U. pumila many phenolic compounds (hidroxibenzoic, ferulic, coumaric, protocatechuic, vanillic and rosmarinic acids, and quercetin) were detected.project POII10-0179-4700 of the Junta de Comunidades de Castilla La ManchaPeer reviewe

Allelopathic potential of invasive Ulmus pumila on understory plant species

In Petriplate bioassay and Pot culture, we studied the allelopathic potential of leaf litter of Siberian elm (Ulmus pumila L.) invasive tree species on the germination and growth of three herbaceous plant native species (Dactylis glomerata L., Trifolium repens L. and Chenopodium album L.) commonly found in riparian understory communities. Two assays were done with leaf litter of U. pumila from riverine ecosystems (i). the effects of aqueous litter extracts in Petri dish assays and (ii). the effect of litter residues in pot experiments. The leaf litter extracts inhibited the radicle growth of D. glomerata and T. repens but did not effect the germination. However in pots, leaf litter inhibited the germination speed of C. album and growth of D. glomerata and T. repens. Our results showed the allelopathic potential of U. pumila litter, which reduced the growth of understory species (T. repens and D. glomerata). In the litter of U. pumila many phenolic compounds (hidroxibenzoic, ferulic, coumaric, protocatechuic, vanillic and rosmarinic acids, and quercetin) were detected

Efecto alelopático de especies invasoras de ribera sobre la germinación de especies del sotobosque

9 páginas. -- Trabajo presentado en la 50ª Reunión Científica de la SEEPLa producción de sustancias alelopáticas por las especies vegetales contribuye a incrementar su éxito competitivo frente a otras especies coexistentes dentro de un mismo hábitat, pudiendo llegar incluso a eliminarlas. Las sustancias alelopáticas pueden inhibir la germinación y el crecimiento de otras especies de la comunidad. En los bosques de ribera se ha detectado la presencia de árboles exóticos con potencial invasor en otros ecosistemas pero se desconoce su efecto sobre las especies autóctonas herbáceas. Nuestra hipótesis es que las especies invasoras podrían utilizar la producción de aleloquímicos de una manera eficiente para desplazar a las especies herbáceas autóctonas, pudiendo llegar a eliminarlas. El objetivo del presente trabajo fue estudiar el efecto extractos de hojarasca de especies alóctonas arbóreas (Ulmus pumila, Robinia pseudoacacia, Ailanthus altissima) y autóctonas (Populus alba) sobre la germinación de cuatro especies herbáceas frecuentes en el sotobosque del bosque de ribera del rio Henares (Madrid). Los resultados mostraron una disminución de la velocidad de germinación de B. phoenicoides y B. sylvaticum con los extractos de las especies alóctonas y autóctonas excepto para el olmo siberiano. Chenopodium album no se vio perjudicada por los extractos de las especies alóctonas pero sí por lo de la especie autóctona. La velocidad de germinación de Dactylis glomerata fue afectada por los extractos de todas las especies alóctonas. Se concluye que no existe un efecto consistente de los extractos de las hojas de árboles exóticos sobre las herbáceas nativas, sino que éstos dependen tanto de la naturaleza del árbol donante como de la herbácea receptora.Plants produce allelopathic substances increasing their competitive success over other species coexisting within the same habitat, being able to eliminate them. Allelopathic substances inhibit germination and growth of other species in the community. In the riverside forests, it has been detected, the presence of invasive tree species with demonstrated invasive potential in other ecosystems. Our hypothesis is that invasive species could use the production of allelochemicals in an efficient way to compete against native herbaceous species. The aim of this work was to assess the effects of leaf extracts of invasive species (Ulmus pumila, Robinia pseudoacacia, Ailanthus altissima) and native (Populus alba) on the germination of four grass species frequent in the forest understory bank of the river Henares (Madrid). The results showed that extracts of alien and native species (except Siberian elm) decreased the germination speed of B. phoenicoides and B. sylvaticum. The effect of extracts in Chenopodium album was not clear. The extracts of all alien species affected the germination speed of Dactylis glomerata.Agradecemos la ayuda de la Dra. Teodora Martínez en la localización de las zonas de campo. Este trabajo ha sido financiado por los proyectos POII10-0179-4700 de la Junta de Castilla La Mancha y CGL2010-16388/BOS del Ministerio de Ciencia e Innovación.Peer reviewe

Territorial dynamics and boundary effects in a protected area of the Central Iberian Peninsula

We analysed the main changes in land use over a 21 year period within the perimeter of a Protected Natural Area (PNA) and outside this perimeter. The area is characterised by its Mediterranean mid-mountain landscape and its piedmont, which extends almost as far as the city of Madrid. We employed cartography of land use and plant formation from 1980 and 2001. We identified land uses and their changes in this time period in order to determine the principal territorial dynamics (scrub encroachment, urban development, forest encroachment, new pastures and new crops). Subsequently, we performed a comparative analysis between the changes inside and those outside the protected area. The results show that there is a boundary effect between the protected area and the surrounding zone, which is more notable in the areas where urban development has intensified. This kind of research serves to establish whether or not a PNA contributes to protecting and conserving natural resources as compared to what occurs in the unprotected surrounding area, which tends to be subjected to more aggressive dynamics

Comparing the allelopathic potential of exotic and native plant species on understory plants: are exotic plants better armed?

Allelopathy is thought to be a key mechanism in biological invasions. Our study aimed to assess the effects of aqueous extracts of leaves from three different exotic tree species common in Spanish riparian forests on the germination of six herbaceous species common in the understory of these ecosystems. We compared the effects of exotic species with those of a native tree species, the white poplar. Our results showed that germination speed and radicle growth of target species were the variables more sensitive to extracts, while percent germination was barely affected. Mostly, extracts had a negative effect on germination speed and radicle growth of all species, except Chenopodium album. White poplar extracts caused similar or even more negative effects than those of the exotic species. Our results show that allelopathy a complex phenomenon, in which native species are also involved

Comparing the allelopathic potential of exotic and native plant species on understory plants: are exotic plants better armed?

La alelopatía es un mecanismo clave en las invasiones biológicas. Este estudio se propuso analizar el efecto de extractos acuosos de hojas de tres especies de árboles exóticos comunes en bosques ri- parios españoles sobre la germinación de seis herbáceas comunes en su sotobosque. Comparamos los efectos de las especies exóti- cas con los de una especie de árbol nativo, el álamo blanco. Las variables más sensibles a los extractos fueron la velocidad de ger- minación y el crecimiento radicular, mientras que el porcentaje de germinación apenas fue afectado. Principalmente, los extractos tu- vieron un efecto negativo sobre la germinación de todas las espe- cies, excepto Chenopodium album. El álamo blanco causó efectos similares o incluso más negativos que las especies exóticas. Nues- tros resultados muestran que la alelopatía es un fenómeno com- plejo, en el que las especies nativas también están involucradas

α-Hispanolol Induces Apoptosis and Suppresses Migration and Invasion of Glioblastoma Cells Likely via Downregulation of MMP-2/9 Expression and p38MAPK Attenuation

α-Hispanolol (α-H) is a labdane diterpenoid that has been shown to induce apoptosis in several human cancer cells. However, the effect of α-H in human glioblastoma cells has not been described. In the present work, we have investigated the effects of α-H on apoptosis, migration, and invasion of human glioblastoma cells with the aim of identifying the molecular targets underlying its mechanism of action. The results revealed that α-H showed significant cytotoxicity against human glioma cancer cell lines U87 and U373 in a concentration- and time-dependent manner. This effect was higher in U87 cells and linked to apoptosis, as revealed the increased percentage of sub-G1 population by cell cycle analysis and acquisition of typical features of apoptotic cell morphology. Apoptosis was also confirmed by significant presence of annexin V-positive cells and caspase activation. Pretreatment with caspase inhibitors diminishes the activities of caspase 8, 9, and 3 and maintains the percentage of viable glioblastoma cells, indicating that α-H induced cell apoptosis through both the extrinsic and the intrinsic pathways. Moreover, we also found that α-H downregulated the anti-apoptotic Bcl-2 and Bcl-xL proteins and activated the pro-apoptotic Bid and Bax proteins. On the other hand, α-H exhibited inhibitory effects on the migration and invasion of U87 cells in a concentration-dependent manner. Furthermore, additional experiments showed that α-H treatment reduced the enzymatic activities and protein levels of matrix metalloproteinase MMP-2 and MMP-9 and increased the expression of TIMP-1 inhibitor, probably via p38MAPK regulation. Finally, xenograft assays confirmed the anti-glioma efficacy of α-H. Taken together, these findings suggest that α-H may exert anti-tumoral effects in vitro and in vivo through the inhibition of cell proliferation and invasion as well as by the induction of apoptosis in human glioblastoma cells. This research describes α-H as a new drug that may improve the therapeutic efficacy against glioblastoma tumors.This study was supported by grant PI11/00036, PI14/00055, and PI17/00012 from the FIS, MPY 1410/09 from ISCIII and Spanish Ministry of Health (Instituto de Salud Carlos III; RD12/0036/0059) to SoH and by grants IERPY 1149/16 and IERPY-M 389/18 to AL. L JG was supported by FIS (FI12/00340). SaH was supported by IERPY 1149/16 from ISCIII.S