EFECTO DE LA MICORRIZA ARBUSCULAR EN PLANTAS DE CAFÉ (Coffea arabica L.) INFECTADAS POR EL NEMATODO DE LA CORCHOSIS DE LA RAÍZ

Arbuscular mycorrhizae may reduce the susceptibility and damagescaused by pathogens. Coffee is a crop that has a high degree ofmycotrophy and it has been proven that mycorrhizas improve plantdevelopment. The purpose of this study was to compare the effectof plants inoculated with consortia of mycorrhizal fungi and theirinteraction with phytopathogenic nematodes. Seven consortia ofnative coffee plantation mycorrhizae fungi were isolated, and theinteraction of the different inoculums was compared with the rootknotnematode that causes coffee corky-root disease, also calledcorchosis. For this purpose, coffee plants were inoculated with theseven consortia of AMF and after seven months they were inoculatedwith 1500 juveniles and eggs; the following were defined: dry weight,root volume, leaf area and number of leaves, extraradical mycelium,chlorophyll quantity, percentage of colonization, number of spores,and population of nematodes. The root system volume of plantsinoculated with the pathogen decreased by up to 70.93%; however, theplants observed were apparently healthy and vigorous in the aerial part,which leads us to assume that although the nematode penetrates theroot and damages it, the fungal hyphae allow the passage of nutrientsand therefore the plant attains its development.La micorriza arbuscular puede reducir la susceptibilidad y daños causados por patógenos. El café es un cultivo que presentaun alto grado de micotrofía y ha sido comprobado que la micorriza mejora el desarrollo de la planta. En este trabajose comparó el efecto de plantas inoculadas con consorcios de hongos micorrízicos y su interacción con nematodosfitopatógenos. Se aislaron siete consorcios de hongos micorrízicos nativos de cafetales y se comparó la interacción delos diferentes inóculos con el nematodo causante de la “corchosis”. Para ello se sembraron plantas de café inoculadascon los siete consorcios de HMA y después de siete meses se inocularon con 1500 juveniles y huevecillos y se determinóel peso seco, volumen radical, área foliar y número de hojas, micelio extraradical, cantidad de clorofila, porcentaje decolonización micorrízica, número de esporas y la población de nematodos. El volumen radical de las plantas inoculadascon el patógeno disminuyó hasta en un 70.93%, sin embargo, las plantas se observaban aparentemente sanas y vigorosasen la parte área, lo que nos hace suponer que aunque el nematodo penetra en la raíz y la daña, las hifas del hongospermiten el paso de nutrimentos y así la planta logra su desarrollo

HONGOS MICORRÍZICOS ARBUSCULARES EN EL CRECIMIENTO DE CAFÉ (Coffea arabica L.) VARIEDADES GARNICA, CATIMOR, CATURRA Y CATUAÍ

Arbuscular mycorrhizal fungi can increase yield, improving growth and the vegetative development of coffee plants. The introduction of arbuscular mycorrhizas during nursery stay increases the fungalbenefits since the adequate management of mycorrhizal inoculum favors the production of more vigorous coffee seedlings at low cost. The effect of two mycorrhizal inoculants was studied: Zac-19 (formed by tree fungal species) and other monospecific (Rhizophagus aggregatus) in four coffee varieties (Garnica, Catimor, Caturra and Catuaí). The plants were inoculated from seed and remained in the nursery for eleven months. The inoculum Zac-19 was the most effective in promoting plant growth and development. Significant differences were obtained between treatments and increments with respect to the control in height (198%), foliar area (676%), root volume (910%) and dry weight (1,063%). Regarding all coffee varieties, it was observed that R. aggregatus was not as efficient as Zac-19, but significantly increased all variables; except plant height. Catuaí variety did not respond favorably to mycorrhizal inoculation. The plant inoculation with Zac-19 allowed obtaining healthy and vigorous plants for field transplant sooner than in the control plants. The use of this fungal inoculum is recommended for coffee nurseries.Los hongos micorrízicos arbusculares pueden incrementar el rendimiento, mejorar el crecimiento y desarrollo vegetativo de las plantas en café. La introducción en vivero de estos hongos es de suma importancia, debido a que el manejo adecuado del inóculo fúngico favorece la producción de plántulas de cafeto más vigorosas a bajo costo. Se estudió el efecto de dos inóculos micorrízicos: uno Zac-19, formado por tres especies y otro monoespecífico (Rhizophagus aggregatus), en cuatro variedades de café (Garnica, Catimor, Caturra y Catuaí). Las plantas permanecieron en vivero once meses, se inoculó desde semilla para evaluar su efecto en las plantas. El inóculo Zac-19 fue más eficiente en promover el crecimiento y desarrollo de las plantas. Se obtuvieron diferencias significativas entre tratamientos e incrementos con respecto al testigo en altura (198%), área foliar (676%), volumen de la raíz (910%) y peso seco (1,063%). Al considerar todas las variedades de café, se observó que R. aggregatus no fue tan eficiente como Zac-19 pero, mostró incrementos significativos con respecto al tratamiento testigo en todas las variables, excepto en altura. La variedad Catuaí no respondió favorablemente a la inoculación micorrízica. Se recomienda la inoculación en el vivero de las plantas de café con Zac-19 y realizar comparación de costos y el tiempo necesario para que plantas inoculadas y las testigo se trasplanten a campo

The role of asymmetric interactions on the effect of habitat destruction in mutualistic networks

Plant-pollinator mutualistic networks are asymmetric in their interactions: specialist plants are pollinated by generalist animals, while generalist plants are pollinated by a broad involving specialists and generalists. It has been suggested that this asymmetric ---or disassortative--- assemblage could play an important role in determining the equal susceptibility of specialist and generalist plants under habitat destruction. At the core of the argument lies the observation that specialist plants, otherwise candidates to extinction, could cope with the disruption thanks to their interaction with generalist pollinators. We present a theoretical framework that supports this thesis. We analyze a dynamical model of a system of mutualistic plants and pollinators, subject to the destruction of their habitat. We analyze and compare two families of interaction topologies, ranging from highly assortative to highly disassortative ones, as well as real pollination networks. We found that several features observed in natural systems are predicted by the mathematical model. First, there is a tendency to increase the asymmetry of the network as a result of the extinctions. Second, an entropy measure of the differential susceptibility to extinction of specialist and generalist species show that they tend to balance when the network is disassortative. Finally, the disappearance of links in the network, as a result of extinctions, shows that specialist plants preserve more connections than the corresponding plants in an assortative system, enabling them to resist the disruption.Comment: 14 pages, 7 figure

The Science Performance of JWST as Characterized in Commissioning

This paper characterizes the actual science performance of the James Webb Space Telescope (JWST), as determined from the six month commissioning period. We summarize the performance of the spacecraft, telescope, science instruments, and ground system, with an emphasis on differences from pre-launch expectations. Commissioning has made clear that JWST is fully capable of achieving the discoveries for which it was built. Moreover, almost across the board, the science performance of JWST is better than expected; in most cases, JWST will go deeper faster than expected. The telescope and instrument suite have demonstrated the sensitivity, stability, image quality, and spectral range that are necessary to transform our understanding of the cosmos through observations spanning from near-earth asteroids to the most distant galaxies

Observation of Two Excited B-c(+) States and Measurement of the B-c(+) (2S) Mass in pp Collisions at root s=13 TeV

Signals consistent with the B-c(+)(2S) and B-c*(+)(2S) states are observed in proton-proton collisions at root s = 13 TeV, in an event sample corresponding to an integrated luminosity of 143 fb(-1), collected by the CMS experiment during the 2015-2018 LHC running periods. These excited (b) over barc states are observed in the B-c(+)pi(+)pi(-) invariant mass spectrum, with the ground state B-c(+) reconstructed through its decay to J/psi pi(+). The two states are reconstructed as two well-resolved peaks, separated in mass by 29.1 +/- 1.5(stat) +/- 0.7(syst) MeV. The observation of two peaks, rather than one, is established with a significance exceeding five standard deviations. The mass of the B-c(+)(2S) meson is measured to be 6871.0 +/- 1.2(stat) +/- 0.8(syst) +/- 0.8(B-c(+)) MeV, where the last term corresponds to the uncertainty in the world-average B-c(+) mass.Peer reviewe

Search for MSSM Higgs bosons decaying to mu(+)mu(-) in proton-proton collisions at root s=13TeV

A search is performed for neutral non-standard-model Higgs bosons decaying to two muons in the context of the minimal supersymmetric standard model (MSSM). Proton-proton collision data recorded by the CMS experiment at the CERN Large Hadron Collider at a center-of-mass energy of 13 TeV were used, corresponding to an integrated luminosity of 35.9 fb(-1). The search is sensitive to neutral Higgs bosons produced via the gluon fusion process or in association with a b (b) over bar quark pair. No significant deviations from the standard model expectation are observed. Upper limits at 95% confidence level are set in the context of the m(h)(mod+) and phenomenological MSSM scenarios on the parameter tan beta as a function of the mass of the pseudoscalar A boson, in the range from 130 to 600 GeV. The results are also used to set a model-independent limit on the product of the branching fraction for the decay into a muon pair and the cross section for the production of a scalar neutral boson, either via gluon fusion, or in association with b quarks, in the mass range from 130 to 1000 GeV. (C) 2019 The Author(s). Published by Elsevier B.V

Combination of CMS searches for heavy resonances decaying to pairs of bosons or leptons

CMS Collaboration: et al.A statistical combination of searches for heavy resonances decaying to pairs of bosons or leptons is presented. The data correspond to an integrated luminosity of 35.9 fb collected during 2016 by the CMS experiment at the LHC in proton-proton collisions at a center-of-mass energy of 13 TeV. The data are found to be consistent with expectations from the standard model background. Exclusion limits are set in the context of models of spin-1 heavy vector triplets and of spin-2 bulk gravitons. For mass-degenerate W′ and Z′ resonances that predominantly couple to the standard model gauge bosons, the mass exclusion at 95% confidence level of heavy vector bosons is extended to 4.5 TeV as compared to 3.8 TeV determined from the best individual channel. This excluded mass increases to 5.0 TeV if the resonances couple predominantly to fermions.Individuals have received support from the Marie-Curie program and the European Research Council and Horizon 2020 Grant, contract Nos. 675440, 752730, and 765710 (European Union); the Programa Estatal de Fomento de la Investigación Científica y Técnica de Excelencia María de Maeztu, grant MDM-2015-0509 and the Programa Severo Ochoa del Principado de Asturias