In vitro morphogenesis of grapevine (Vitis vinifera L.) originated from anticipated or latent buds

While in outdoor-grown vines shoots originate from latent buds, grapevine shoots from microcuttings cultured in vitro are produced by the anticipated bud. The latter shoots show physiological and morphological features of juvenility. This study was carried out to obtain more conform in vitro grapevine shoots. Latent buds were induced to develop in vitro. Shoots produced by latent buds had more juvenile features than those produced by anticipated buds. New information on the control of juvenility of grapevines in vitro is presented

An exploratory social network analysis of academic research networks

For several decades, academics around the world have been collaborating with the view to support the development of their research domain. Having said that, the majority of scientific and technological policies try to encourage the creation of strong inter-related research groups in order to improve the efficiency of research outcomes and subsequently research funding allocation. In this paper, we attempt to highlight and thus, to demonstrate how these collaborative networks are developing in practice. To achieve this, we have developed an automated tool for extracting data about joint article publications and analyzing them from the perspective of social network analysis. In this case study, we have limited data from works published in 2010 by England academic and research institutions. The outcomes of this work can help policy makers in realising the current status of research collaborative networks in England

The potential relationship of stilbene (resveratrol) synthesis to anthocyanin content in grape berry skins

The relationship between the production of resveratrol, a phytoalexin related to grape disease resistance, and the anthocyanin content of grape berries in diverse Vitis species has been investigated. Previous studies have reported that the phytoalexin production potential of grapes suddenly declines at veraison. The results obtained here from assaying resveratrol and anthocyanins from grape berries in different developmental stages suggest that chalcone synthase (EC 2.3.1.74), the key enzyme involved in anthocyanin biosynthesis, may compete with stilbene (resveratrol) synthase (EC 2.3.1.-), such that the decrease of the ability of grapes to synthesize resveratrol in response to UV-irradiation observed after the onset of fruit ripening may be a consequence of the concomitant rise of anthocyanin accumulation in fruits

Lectures on the Asymptotic Expansion of a Hermitian Matrix Integral

In these lectures three different methods of computing the asymptotic expansion of a Hermitian matrix integral is presented. The first one is a combinatorial method using Feynman diagrams. This leads us to the generating function of the reciprocal of the order of the automorphism group of a tiling of a Riemann surface. The second method is based on the classical analysis of orthogonal polynomials. A rigorous asymptotic method is established, and a special case of the matrix integral is computed in terms of the Riemann $\zeta$-function. The third method is derived from a formula for the $\tau$-function solution to the KP equations. This method leads us to a new class of solutions of the KP equations that are \emph{transcendental}, in the sense that they cannot be obtained by the celebrated Krichever construction and its generalizations based on algebraic geometry of vector bundles on Riemann surfaces. In each case a mathematically rigorous way of dealing with asymptotic series in an infinite number of variables is established

Endogenous polyamine concentrations in juvenile, adult and micropropagated grapevine (Vitis vinifera L. cv. Pinot noir)

Research Not

Corrections to Sirlin's Theorem in O(p6)O(p^6) Chiral Perturbation Theory

We present the results of the first two-loop calculation of a form factor in full $SU(3) \times SU(3)$ Chiral Perturbation Theory. We choose a specific linear combination of $\pi^+, K^+, K^0$ and $K\pi$ form factors (the one appearing in Sirlin's theorem) which does not get contributions from order $p^6$ operators with unknown constants. For the charge radii, the correction to the previous one-loop result turns out to be significant, but still there is no agreement with the present data due to large experimental uncertainties in the kaon charge radii.Comment: 6 pages, Latex, 2 LaTeX figure

Etude de la toxicité du filtrat de culture de Botrytis cinerea sur des vitroplants de vignes: I. Effet du filtrat brut

Study of culture filtrate toxicity of Botrytis cinerea observed on grapevine vitroplants:I. Effect of crude culture filtrateThe purpose of this research was: to show culture filtrate toxicity of Botrytis cinerea,to determine an eventual relation between susceptibility of grapevines to B. cinerea in the field and susceptibility of in vitro plantlets to fungal culture filtrate.In this way, effects of culture filtrate on the growth of vitroplants were examined to evaluate on the one hand, susceptibility of Vitis and, on the other, degree of culture filtrate toxicity. Growth inhibition increased with grapevine sensitivity and no phytotoxic effects were observed on resistant grapevines. So a discrimination between resistant, susceptible and very susceptible grapevines was achieved. A comparative study has also shown that factors like fungal culture age or isolate nature were able to affect toxicity. 1-week-old culture filtrate was able to induce symptoms on vitroplants and toxicity increased with fungal culture age. Moreover, this was not due to enzyme activity

Eigenvalues of PT-symmetric oscillators with polynomial potentials

We study the eigenvalue problem $-u^{\prime\prime}(z)-[(iz)^m+P_{m-1}(iz)]u(z)=\lambda u(z)$ with the boundary conditions that $u(z)$ decays to zero as $z$ tends to infinity along the rays $\arg z=-\frac{\pi}{2}\pm \frac{2\pi}{m+2}$, where $P_{m-1}(z)=a_1 z^{m-1}+a_2 z^{m-2}+...+a_{m-1} z$ is a polynomial and integers $m\geq 3$. We provide an asymptotic expansion of the eigenvalues $\lambda_n$ as $n\to+\infty$, and prove that for each {\it real} polynomial $P_{m-1}$, the eigenvalues are all real and positive, with only finitely many exceptions.Comment: 23 pages, 1 figure. v2: equation (14) as well as a few subsequent equations has been changed. v3: typos correcte

Resveratrol content of two Californian table grape cultivars

Research Note

Etude de la toxicité du filtrat de culture de Botrytis cinerea sur des'vitroplants de vignes: II. Effet des différentes fractions isolées a partir du filtrat brut

Study of culture filtrate toxicity of Botrytis cinerea observed on grapevine vitroplants:II. Effect of various fractions isolated from the crude culture filtratePolysaccharides secreted by Botrytis cinerea were isolated from the crude culture filtrate and precipitated as two fractions: glucan and heteropolysaccharides. The fraction containing heteropolysaccharides was further separated into two sub-fractions. The phytotoxic activities of the various fractions were tested on vitroplants from several grapevines differing in their sensitivity to B. cinerea. With glucan, no toxic effects on the growth of vitroplants were observed. The heteropolysaccharides showed specific phytotoxic activities which were identical with the effects of the culture filtrate: plants susceptible to the pathogen were also susceptible to the heteropolysaccharides, and vice versa