Micropropagación de Actinidia chinensis Planch. (Kiwi). Optimización del medio de cultivo para la propagación clonal en gran escala

La micropropagación en escala comercial de kiwi (Actinidia chinensis Planch.) cv.Hayward fue posible a partir de la siembra de ápices extraídos de yemas dormidas.El establecimiento y crecimiento del explanto se logró con el cultivo en medio MS(1962). los compuestos orgánicos de Standards (1983),209. L-1 sacarosa, sin auxinasy con el agregado de 1 mg. L-1 de BAy 0,1 mg. L-1 de GA3. El empleo de ANA determinó la formación de un callo basal y el crecimiento anormal de la yema.La brotación de las yemas axilares se obtuvo con un medio compuesto por las sales de MS, los componentes orgánicos de Standards (1983) e idéntica composición de reguladores del crecimiento. En esta forma se obtuvieron 4-5 brotes por expíenlo cada 30 días, en condiciones de iniciar el enraizamiento. Esto se logró con la reducción al 50% de los macro-nutrientes de MS, IBA y PPZ, éstos últimos a razón de1 mg.L-1. El porcentaje de enraizamiento llegó al 95% al cabo de 30 días, con la producción de cerca de 1000 plantitas usticadas.Abreviaturas. ANA: ácido naft-1 -y lacético; BA: H-(fenilmetil)-1 H-purin-6-amina; GA3:ácido giberélico; IBA: ácido 1H-indol-3-butanoico; MS: medio de Murash

Adesmia horrida Gillies ex Hook. & Arn.

Valle del Río BonetepublishedVersio

Adesmia trijuga Gillies ex Hook. & Arn.

Valle del Río Bonete, entre Yegua Quemada y Junes GrandespublishedVersio

Euphorbia ruiz-lealii Subils

Valle del Río BonetepublishedVersio

Cistanthe minuscula (Añon) Peralta

Valle del Río BonetepublishedVersio

Portulaca tingoensis D. Legrand var. andina (D. Legrand) D. Legrand

Valle del Río BonetepublishedVersio

The potential for production of high quality seed potatoes in Tierra del Fuego Island, Argentina

In Argentina, different areas are suitable for seed potato production: however, each has particular problems, mainly related to different pest and diseases. Tierra del Fuego Island is well isolated from traditional potato growing areas. Therefore, it was tested for its potential for seed production. The cultivars Achatt. Mailen INTA. Pampeana INTA and Spunta were grown in Rio Grande, San Pablo and Ushuaia from 1991–1994. Nematode presence and aphid population dynamics were recorded. Average tuber yield ranged from 20.1–37.6 t ha−1. After three years PVY and PLRV remained low (0–1% for different cultivars and locations). Moreover, seed tubers obtained were physiologically young. Long days, early frosts and strong winds may limit tuber yield in some years. The island can be considered as an ecological “safe haven” and is very suitable to obtain healthy and physiologically adequate seed potatoes.Instituto de Fisiología Vegeta

Limits on excited tau leptons masses from leptonic tau decays

We study the effects induced by excited leptons on the leptonic tau decay at one loop level. Using a general effective lagrangian approach to describe the couplings of the excited leptons, we compute their contributions to the leptonic decays and use the current experimental values of the branching ratios to put limits on the mass of excited states and the substructure scale.Comment: 10 pages, 6 figures, to be published in Phys. Rev.

The Neutrino Magnetic Moment Induced by Leptoquarks

Allowing leptoquarks to interact with both right-handed and left-handed neutrinos (i.e., ``non-chiral'' leptoquarks), we show that a non-zero neutrino magnetic moment can arise naturally. Although the mass of the non-chiral vector leptoquark that couples to the first generation fermions is constrained severely by universality of the $\pi^+$ leptonic decays and is found to be greater than 50 TeV, the masses of the second and third generation non-chiral vector leptoquarks may evade such constraint and may in general be in the range of $1\sim 100$ TeV. With reasonable input mass and coupling values, we find that the neutrino magnetic moment due to the second generation leptoquarks is of the order of $10^{-12}\sim 10^{-16} \mu_{\rm B}$ while that caused by the third generation leptoquarks, being enhanced significantly by the large top quark mass, is in the range of $10^{-10}\sim 10^{-14} \mu_{\rm B}$.Comment: 11 pages, 3 eps figures, uses revte

Leptoquark Contribution to the Higgs Boson Production at the LHC Collider

In this report we study how a light-scalar leptoquark could affect the Higgs boson production cross-section at the LHC collider. We construct the most general renormalizable and gauge invariant effective Lagrangian involving the standard model particles and a scalar, isoscalar leptoquark, \eta. The total cross-section for pp -> H+X is then calculated for different values of the unknown parameters \lambda_eta, m_eta and m_H.(Here \lambda_eta is the coupling associated with the Higgs-leptoquark interaction.) We find that if \lambda_eta is moderately large and m_eta is around a few hundred GeV, then the cross-section is significantly larger than the standard model value.Comment: 9 pages, 4 postscript figure